RU2670309C2 - Low-noise technical room - Google Patents

Abstract

The invention relates to the field of technical means of ensuring acoustic safety of the environment due to the suppression (reduction) of noise emissions produced by production and technological and engineering equipment, represented, in particular, pumping, compressor stations, power plants (internal combustion engines, diesel generator installations), ventilation and air conditioning systems, electrical machines (electric motors, electrical transformers), inside the noise-generating (noise-active) technical premises (building buildings). The technical room contains supporting fencing rigid sound-reflecting elements in the form of walls, ceiling, floor, doorway with closed entrance door, inlet and exhaust ventilation openings, forming an internal three-dimensional air cavity, represented by a rectangular parallelepiped with overall dimensions A (L⋅B⋅H). It is characterized by certain physical parameters of the sound and temperature field in which at least one noise-generating technical object operated is installed, operating in a given steady-state high-speed operating mode n _s , accompanied by physical processes of radiation of sound and thermal energy. The spectral sound composition of the radiation of the noise-generating technical object contains prominent discrete values of the working dominant functional frequencies f _ms , characterized by the corresponding sound wavelengths λ _ms . At least one of the overall parameters A of the internal three-dimensional air cavity of a technical room, represented by a rectangular parallelepiped with overall dimensions L⋅B⋅H, meets the requirements of an interconnected relationship with the physical parameters of the sound and temperature field of the internal three-dimensional air cavity of a technical room, allowing to exclude resonant frequency modal interaction of sound radiation of a noise-generating technical object with its own acoustic modes (natural frequencies of sound vibrations f _mA ) of the internal three-dimensional air cavity of the technical room, defined by the expression:

,

,

звуковых волн рабочей доминирующей функциональной частоты f_ms звукового излучения шумогенерирующего технического объекта, укладывающихся в ограничительных пределах габаритного параметра А, характеризующего габаритные размеры внутренней трехмерной воздушной полости технического помещения (L, В, Н); K_t - температурный коэффициент коррекции скорости звука с и длины звуковой волны λ_ms рабочей доминирующей функциональной частоты f_ms, излучаемой шумогенерирующим техническим объектом на заданном установившемся скоростном эксплуатационном режиме работы n_s, в эксплуатационном диапазоне изменения температуры воздуха Δt°C во внутренней трехмерной воздушной полости технического помещения (L, В, Н). Реализация заявленного технического решения позволяет предотвратить возникновение воздушных полостных акустических резонансов и физических явлений биений взаимодействующих акустических сигналов (звуковых волн) с близкими значениями частот звуковых колебаний f_ms и f_mA в техническом помещении со смонтированным в нем шумогенерирующим техническим объектом. 30 ил., 3 табл.

where n _vs is an integer (natural number) half-length

sound waves of the working dominant functional frequency f _{ms of} sound radiation of a noise-generating technical object that falls within the limiting limits of the overall parameter A, characterizing the overall dimensions of the internal three-dimensional air cavity of the technical room (L, B, H); K _t is the temperature coefficient of correction of the speed of sound with and the sound wavelength λ _{ms of the} working dominant functional frequency f _ms emitted by the noise-generating technical object at a given steady-state operating speed n _s in the operational range of air temperature variation Δt ° C in the internal three-dimensional air cavity technical room (L, B, H). Implementation of the claimed technical solution allows to prevent the occurrence of air cavity acoustic resonances and physical phenomena of the beating of interacting acoustic signals (sound waves) with close values of the frequencies of sound vibrations f _ms and f _mA in the technical room with the noise-generating technical object mounted in it. 30 ill., 3 tab.

Description

The invention relates to the field of technical means of ensuring acoustic safety of the environment due to the suppression (reduction) of noise emissions produced by production and technological and engineering equipment, represented, in particular, pumping, compressor stations, power plants (internal combustion engines, diesel generator installations), ventilation and air conditioning systems, electrical machines (electric motors, electrical transformers), inside the noise-generating (noise-active) technical premises (building buildings). It can also be used to improve acoustic comfort in residential, industrial and public premises of buildings and structures, integrated adjacent (closely spaced) with the specified noise-generating technical premises (building buildings).

It is known that to protect the environment from intense acoustic pollution (high noise levels) produced by various types of noise-generating technical objects, various types of sound-insulating (noise-insulating) enclosures of noisy technical premises are widely used (screen partitions, housings, panel linings of carrier and / or enclosure structures equipped with additional layers of viscoelastic vibration-damping and / or porous air mounted on their surfaces repulsive sound-absorbing, and / or dense air-insulated sound-proofing materials, and / or their various combined combinations with the additional inclusion of carrier, reinforcing, acoustic, protective, adhesion, decorative layers of materials or corresponding structural elements). Also, for the same purpose can be used isolated single or interlocked, presented in the form of aggregated modular batteries, various types of acoustic resonators - quarter-wave (R '), half-wave (R "), Helmholtz (R" "), or can be used volumetric expansion chambers connected to the sound transmitting (waveguide) channels (openings) of the corresponding type, blocking (weakening) the transmission of acoustic energy due to the sound-reflecting air (gas-filled) “acoustic waves obok, characterized by abrupt changes in acoustic wave impedances. In the overwhelming majority of cases, various combined combinations of the above types of noise suppressing (noise reducing) methods and technical devices for their implementation are used, and their specific choice is predetermined by both technical and economic factors. The use of such a wide variety of noise-attenuating techniques (methods) and technical devices allows, in one way or another, to provide an acoustically safe noise-comfortable environment for people and animals. In particular, various types of hybrid noise suppression structures are widely used, using the combined realization of the physical processes of sound absorption and sound insulation, where the total noise reduction effect of the used technical device can be based both on the effects of reflection of sound energy and on the combined combination of sound absorption and sound reflection. This type of technical noise-suppressing devices may not include porous air-absorbing sound-absorbing structures, or air-soundproof sound-proofing structures, and the resulting sound attenuation effect can be realized exclusively by the operation of individual frequency-tuned acoustic resonator elements (quarter-wave R ', half-wave R', Helmholtz R '' '), including the use of perforated lamellar structures located with a given air gap flax rigid sound-reflecting surfaces, to form the corresponding cavity resonator devices (acoustic Helmholtz resonators R '' '). This type of cavity resonator devices can be both hollow and partially filled with a porous sound-absorbing substance.

As well-known examples of the use of technical devices for damping acoustic energy that function according to the physical principles noted above, various types of panel-like noise-reducing structures can be mentioned, in particular:

- international application for invention WO 2009/131855 A2 (published 10.29.2009);

- international application for invention WO 2008/138840 A1 (published 11/20/2008);

- international application for invention WO 2009/037765 A1 (published September 20, 2007);

- German patent for invention DE 4315759 (published 05/11/1993);

- international application for invention WO 2006056351 (published January 6, 2006);

- RF patent for invention RU 2206458 (published June 20, 2003);

- French patent for invention FR 2910685 (published June 27, 2008);

- Japanese application for the invention of JP 2008-96826 A (published October 13, 2006);

- Japan’s application for the invention of JP 2007-186186 (published July 26, 2007);

- RF patent for utility model RU 61353 (published February 27, 2007);

- RF patent for utility model RU 67650 (published October 27, 2007).

The pronounced useful advantages of using the above technical devices for damping acoustic energy should include the possibility of their use under the influence of aggressive media, high temperatures and intense dynamic loads, due to the exclusion of the use in their composition of porous air-blowing (gas-blowing) fibrous and / or foamed open-cell structures of organic or synthetic origin characterized, as a rule, not sufficiently high thermo-moisture-biostable and characteristics. In their composition, extremely dense structures of perforated metal or heat-resistant polymeric materials are used, with the possible inclusion of heat-resistant porous fibrous (basalt, glass, metal) and / or foamed open-cell metallic and / or ceramic materials. At the same time, the narrow technical characteristics of this type of noise-suppressing devices should include their narrow working frequency sound range of effective functioning, high sensitivity to frequency detuning when the physical parameters of the sound wave propagation medium are not sufficiently high, and the sound attenuation effect is not high enough. cost, poor overall performance and increased consumption of materials. At the present level of technological development, these negative factors may limit their wide distribution in effectively solving actual practical problems of suppressing acoustic radiation produced by various noise-generating technical objects.

Accordingly, panel-cavity noise-reducing structures are known and widely distributed, the cavities of which are completely or partially filled with porous air-breathing sound-absorbing material of fibrous and / or open-cell foam type (of organic, mineral, synthetic origin), characterized by higher sound-absorbing (noise reducing) characteristics, however sufficiently effective only in a limited range of medium and high frequencies of the sound range it (over 500 Hz). In this type of known noise-reducing structures, the front (front) wall of the acoustic panel is usually perforated and is characterized by a rather high value of the perforation coefficient. This gives it the properties of acceptable sound transparency and provides, in fact, unhindered (with an insignificant, not exceeding 10% effect of sound reflection) the passage of sound waves into the cavity filled with porous sound-absorbing material. Through, mostly round holes or narrow slotted notches with bends, is the most common type of perforation of this type of front wall of the acoustic panel. As examples of this type of known noise reduction technical devices, the following should be noted:

- French patent for invention FR 2899919 (published 10.19.2007);

- French patent for invention FR 2899992 (published 10.19.2007);

- US patent for invention US 3991848 (published 09/16/1974);

- US patent for the invention of US 5422466 (published 11.03.1994);

- Japan patent for the invention of JP 11104898 (published April 20, 1999);

- international application for invention WO 2007/017317 (published February 15, 2007);

- Japan patent for the invention of JP 62165043 (published 07.21.1987);

- German application for invention DE 4332856 (published 09/27/1993);

- European patent for invention EP 1477302 A1 (published 11/17/2004);

- Japanese application for the invention JP 2000034937 (published 02.02.2000);

- German application for invention DE 202004018241 (published 11/24/2004);

- UK patent for invention GB 1579897 (published 03/06/1976);

- German patent for invention DE 4332845 A1 (published 09/27/1993);

- European patent for invention EP 0697051 B1 (published 04/20/1994);

- international application for invention WO 2004/013427 A1 (published February 12, 2004);

- RF patent for invention RU 2042547 (published 08/27/1995).

The above-mentioned known noise reduction technical devices, along with achievable satisfactory acoustic characteristics that are realized in the mid and high frequencies of the sound range, are nevertheless characterized by a certain loss of potential noise-attenuating properties, due to the formation of an abrupt change in the acoustic wave resistance on the flat delimited border (section) of elastic layered sound propagation mediums in the considered zone of the air environment, adjacent it has a flat layered structure, with different values of acoustic wave impedances, in the composition of the adjacent air medium, solid flat wall of the perforated face panel and flat sheet structure of the porous sound-absorbing substance. This causes not only the corresponding potential loss of the sound-absorbing effect, but the perforation holes contained, distributed over the entire solid surface of the flat wall, also cause a certain loss of sound-insulating (in particular, sound-reflecting) properties of the said multilayer structure of the wall partition as a whole. Also, there is a relative high cost of polymer porous sound-absorbing substances used in this type of construction, produced mainly from non-renewable expensive hydrocarbon raw materials (oil, gas). They are also characterized by rather complex, time-consuming and “environmentally dirty” problems of both their production and the final utilization of heterogeneous construction materials used in the parts and components of this type of noise-reducing technical devices after they complete their life cycle.

To increase the noise-reducing properties of this type of construction, by providing a smoother (not abrupt jump-like) matching of acoustic wave impedances on the sound wave propagation paths, in the boundary zones of the elastic air separation of sound waves propagation, including the boundary zones of the contact of the external solid-surface panel of a technical device with the outer and inner abdominal zones of contiguity of the air environment, the contours of the outer shell (wall) of the facial acoustic Coy gofrovidnaya panel attached to non-planar geometric shape (wedge-shaped, wavy, echelon), as is particularly shown in the following prior art devices:

- RF patent for invention RU 2249258 (published September 27, 2004);

- US patent for invention US 4097633 (published 06/27/1978);

- the application of Germany for the invention DE 4237513 (published 07.11.1992);

- US application for invention US 2003207086 (published 11.06.2003);

- European patent for invention EP 0253376 A2 (published 01.20.1988);

- RF patent for invention RU 2161825 (published Jan. 10, 2001);

- Australian application for invention AU 2007100636 (published 08.16.2007).

The above-mentioned noise-reducing structures of technical devices are characterized, first of all, by a significant complication of their technological performance and relatively high cost, with not enough high acoustic insulation capacity (the presence of prominent “soundproofing dips” in separate sound frequency ranges of sound energy suppression characteristics, due to the formation of “parasitic” cavity) air acoustic resonances), as well as forced concomitant arising diminishing using the “displacement” of the useful working volume of the technical room, complicating the processes of their maintenance (cleaning, washing).

Another well-known technical direction for improving the design of technical devices for attenuating the spread of negative (“parasitic”) sound energy generated by vibro-noise technical objects mounted in technical rooms, associated with an increase in the fraction of absorbed sound energy, is the execution of a technical device directly perceiving falling sound waves, perforation holes with given technological tolerances geometrically specific shapes and dimensions. This type of noise-reducing technical devices are known from the following patent documents:

- German patent for invention DE 4315759 СТ (published 05/11/1993);

- US patent for the invention of US 6194052 B1 (published 06/20/1998);

- European patent for invention EP 1146178 A2 (published March 15, 2001);

- European patent for invention EP 1950357 A1 (published 30.07.2000);

- US application for the invention of US 2007/0272472 A1 (published 11/29/2007);

- international application for invention WO 2006/101403 A1 (published September 28, 2006);

- US application for the invention of US 2007/0151800 A1 (published 05.06.2007).

These noise-reducing technical devices can be characterized by improved performance and decorative (improved exterior design) properties. However, their noise-reducing properties are, nevertheless, not high enough due to the limited potential used to improve the efficiency of a structural modification of a technical device based on the rationalization of the geometrical shapes of perforation holes. Also, their production is associated with the need to use more sophisticated high-tech equipment, ensuring compliance with narrow manufacturing tolerances for manufacturing.

Known noise-reducing technical devices, made in the form of composite node (modular) soundproofing fences, the structural elements of which combine combine several techniques (realizable several physical effects), borrowed from the above-considered groups of known technical devices, allowing in varying degrees (in This or that frequency range) purposefully improve their acoustic properties. This type of hybrid hybrid noise reduction technical devices are described in the following patent documents:

- RF patent for invention RU 2295089 (published March 10, 2007);

- French patent for invention FR 2929749 (published 09/10/2009);

- UK patent for invention GB 822954 (published 11/04/1959);

- RF patent for invention RU 2340478 (published December 10, 2008);

- the application of Japan for the invention of JP 2002175083 (published June 21, 2002).

The disadvantages of the above-mentioned noise-reducing technical devices is their higher structural complexity and labor-intensiveness of production, with not sufficiently high (unsatisfactory) environmental and cost indicators being achieved. There are also insufficient potentials for improving their noise damping characteristics in the low frequency range of sound frequencies, which is the most intensive and relevant in solving the problems of noise reduction of machines and equipment.

Known technical solution for the patent of the Russian Federation for invention No. 2465390, published 01.20.2011, which describes the construction of a soundproof fence, made in the form of an autonomous noise-reducing screen, containing in its composition the supporting elements of the type of transverse struts and longitudinal profiles, the corresponding type of noise-absorbing element located from given by the air gap in the cavity between the back sound-reflecting panel and the front sound-transparent panel perforated through holes, with the specified noise absorbing The supporting element contains a perforated or mesh type sheet carrier, fixed with mechanical fasteners to the horizontal profiles and / or the base of the noise reducing screen, lined on at least one of its sides, with separate sound-absorbing panels representing a set of crushed porous fibrous fragments or foamed open mesh. sound-absorbing materials, which are distributed in a certain way and fixedly mounted on the surface of the supporting substrate, with the formation of corresponding air gaps between them. At least on the placement side of the separate sound-absorbing panels, the surface of the noise reducing element is lined with a layer of sound-transparent gas-tight film or fabric. The disadvantage of the analyzed technical solution is the limited possibility of its effective use, carried out mainly not in closed limited volumes of technical premises, but in open spaces of the environment to protect residential areas of settlements from negative acoustic radiation propagating from noise-generating technical objects - vehicles and industrial equipment installed near roads and railways, airfields, open sections of subway lines, test sites, noise-generating construction and production sites, or any other spatially directed sources of increased noise radiation, producing intense acoustic pollution of the environment. This causes, in particular, the need to use in the composition of this type of sound insulation fencing additional bearing and supporting elements (foundation, support base, transverse racks and longitudinal profiles), which significantly complicates the problem of using the specified noise reduction structure, leads to an increase in its weight-dimensional parameters and cost. At the same time, the use of a carrier base in the form of a flat-sheet geometric shape, fixed in a vertical position on horizontal profiles or the base, complicates the technological process of subsequent placement of separate sound-absorbing panels, and also complicates the construction of sound-insulating complex spatial geometric shape. The limited choice of overall dimensions and geometrical forms, physico-mechanical parameters, if necessary to maintain the specified values of air gaps between individual samples of crushed fragments of separate sound-absorbing panels, predetermines the insufficiently effective absorption of sound energy realized in the conditions of a diffuse sound field of closed rooms and is noted in the narrowed working frequency range, characteristic only for spatially expressed local emitters of sound energy in words of the free sound field such as moving vehicles (cars, trucks, buses) or rail transport means in open spaces. The use of this type of soundproofing construction, performed as an autonomous noise-reducing screen (several designs, for subsequent placement inside the technical room, in the areas of its enclosing wall and ceiling structures), will significantly reduce (clutter) its useful working space, worsen the process of technological maintenance of the installed it production and technological and engineering equipment.

Known and used in the technique (architectural acoustics) technique of partial elimination (partial weakening) of the development of the physical process of the formation of pronounced half-wave acoustic resonances of elastic bodies of air volumes, represented by internal three-dimensional air cavities of the rooms, is the use of specialized in the design of the technical room 1, presented in appropriate measuring acoustic instruments, made in the form of a meter hydrochloric reverberation chamber, as described in particular in [1, 2, 3]:

[1] - ASTM with 423-02a. Standart Test Method for Sound Absorption and Sound Absorption Coefficients by Reverberation Room Method. American Society for Testing and Materials International. - West Conshohocken. - 2002. - 11 p .;

[2] - GOST 31274-2004 (ISO 3741: 199) “The noise of machines. Determination of sound power levels by sound pressure. Exact methods for reverberation chambers. ”

[3] - GOST 31704-2011 (ISO 354: 2003) “Sound-absorbing materials. A method for measuring sound absorption in a reverberation chamber ”.

The overall dimensions and geometrical forms of the measuring reverberation chamber, the ratio of its composite dimensions and the physical characteristics of its wall structures make it possible to a certain extent exclude (partially weaken) the development of the physical process of forming the in-phase resonant addition of half-lengths of sound waves (λ / 2) excited inside the measuring air cavity reverberation chamber by the studied noise-generating sound source (or calibrated sound emitter), thereby preventing m Education expressed its own resonant acoustic modes of measuring the air volume of the room reverberation chamber. Thus, this allows the composition of the diffuse acoustic field of the internal air cavity of this type of technical room to partially eliminate (partially weaken) the development of the physical process of forming a pronounced non-uniform spatial density of the distribution of sound energy intensity localized in the air cavity of the measuring reverberation chamber. This type of measuring reverberation chambers are of limited use and are used in the field of acoustic measurements of samples of acoustic materials, as well as studies of the sound-absorbing characteristics of the structures of parts, assemblies and systems of machines performed in a diffused (reverberation) sound field. The regulatory requirements [11, 12, 13] provide, inter alia, instructions on the relevant design principles for measuring reverberation chambers, which impose requirements on the volume (overall dimensions) and the geometric shape of its air cavity, the physical characteristics of the wall structures used, which exclude negative development physical processes of forming pronounced spatial zones of unequal resonant intensity distribution of sound energy, as well as excluding the process of sound absorption Niya, proizvodimomgo enclosing surfaces and wall constructions doorway measuring the reverberation room. However, the alternative use of this type of original constructions of measuring reverberation chambers, as possible typical variant versions of low-noise technical premises 1, with partially eliminated half-wave acoustic resonances, significantly complicates and increases the cost of construction of typical technical premises 1 intended for subsequent installation of SHGTO 14 in them, their design, construction and subsequent operation. An obvious disadvantage of this type of technical room 1, made in the form of measuring reverberation chambers, is also the unsatisfactory (incomplete and inconvenient to use) use of their useful working space, due to the non-parallel opposite surfaces of wall fences, floor, and ceiling. Moreover, in some cases, to ensure the required diffusion of the sound field (uniform spatial density of the sound pressure distribution), the use of the free working space of the room is made difficult by the measuring reverberation chamber used in the air cavity of the additional reflex screen elements mounted in it, which additionally equalizes the spatial density of the sound intensity distribution energy in the air cavity of the measuring reverberation chamber, which is connected of additional unwanted clutter its useful working space.

Known technical solution to the patent of the Russian Federation for invention No. 2579104, published 12/20/2015, taken as a PROTOTYPE, in which a noisy technical room is presented, equipped with a soundproofing lining, made in the form of a soundproofing face plate and / or soundproofing molded non-planar panel, shamefully mounted relative to the surface oppositely located bearing wall (ceiling) structure of the technical room, with the formation of the corresponding closed air cavities. At the same time, quarter-wave acoustic resonators R 'and / or half-wave acoustic resonators R ", frequency-tuned and temperature-adapted for suppressing the resulting air cavities in the air cavities formed, are appropriately fixed to the specified soundproofing front panels and / or supporting wall (ceiling) structures of the technical room. acoustic resonances formed on their own transverse, longitudinal and elevation acoustic modes. A similar function of suppressing the amplitude values of the intrinsic acoustic resonances formed in the air cavities between the opposite walls of the soundproofing front panel of the soundproofing stitching and the supporting wall (ceiling) structure of the technical room are suitably arranged in the specified spatial zones of the air cavities composed of separate sound absorbing modules made up of fragments porous sound absorbing substances.

The disadvantage of the known technical solutions presented in the prototype, is the complexity of its technological performance, as well as the high cost, complexity of installation and maintenance. In addition, this type of known technical solutions have limited application (narrow distribution area of use) for those cases when the use of sound-absorbing materials in the composition of used briquetted sound-absorbing modules (polymer, mineral) is unacceptable for reasons of increased fire safety requirements, durability, reliability, possible deterioration their functional properties due to the negative impact of external factors (environment, technogenic effects, etc.). ). The use of a soundproofing construction known from the prototype also reduces the volume of the useful (working) space of the technical room caused by its corresponding partial blocking "displacement", which is shamefully mounted by the elements of the soundproofing sewing, relative to the internal surfaces of the wall (ceiling) structures of the technical room. The use of the technical solution presented in the prototype is intended primarily to provide additional improvement of sound insulation of the wall structures of the technical room by blocking the transmission of sound energy by air from the air space of the technical room to the outside (to adjacent rooms and / or to open space), and / or transmitted from adjacent (adjacent) noisy rooms or from a noisy open space inside the cavity of the technical room. However, the implementation of such a technical solution according to the prototype does not affect (does not affect) the development of physical processes contributing to the formation of cavitary air acoustic resonances formed inside the working space of a three-dimensional (three-dimensional) air cavity of a technical room formed (limited) by appropriate soundproofing front panels. According to the prior art, it is realized only limited localized parietal air cavities (air gap) formed between the opposing surfaces of the sound-insulating facial ploskolistovyh panels soundproofing linings and sound-reflecting envelope panels bearing elements (walls, ceilings, interior partitions) technical room due to the respective support installation in the formed air gaps (air cavities) of various types of noise-suppressing structural elements (quarter wave R 'and / or half-wave R' acoustic resonators, and / or separate briquetted sound-absorbing modules).

The technical device “Low noise technical room” declared as an invention is aimed at eliminating the identified and analyzed shortcomings of the analogues and the prototype with regard to the simplicity of its implementation, manufacturability, cost and operating efficiency.

Comparison of scientific, technical and patent documents on the priority date in the main and adjacent headings of the MKI shows that the set of essential features of the claimed technical solution was not previously known, therefore, it meets the condition of patentability "novelty."

Analysis of the known technical solutions in this field of technology has shown that the claimed low-noise technical room has signs that are not present in the known technical solutions, and using them in the claimed combination of features makes it possible to obtain a new technical result, therefore, the proposed technical solution involves an inventive step compared to with the current level of technology.

The proposed technical solution is industrially applicable, because can be manufactured industrially, workable, feasible and reproducible, therefore, meets the condition of patentability "industrial applicability".

The features and advantages of the claimed invention will become clear from the presented drawings and the following detailed description of the device, where:

- in fig. 1 shows the experimental results of measurements of the sound pressure spectrum (FFT spectrum) emitted by a noise-generating technical object (ShGTO 14), represented by a closed-type electrical transformer substation (ETPZT) located in the technical room of the basement floor of the test center of an industrial enterprise. The measuring microphone was located outside the technical room 1 at a height of 1.2 m from the surface of its floor, at a distance of 1 m from the doorway 9 of the technical room 1 ETPZT blocked by an entrance door 10;

- in fig. 2 shows the experimental results of measurements of the spectrum of the sound pressure (FFT spectrum) emitted by the ShGTO 14, presented by a 3MK 260-1 power transformer of the company PLATTHAUS (Germany), located in the technical room 1 of the test center of an industrial enterprise. The measuring microphone was located inside the technical room 1 at a distance of 0.5 m from the body of the electrical transformer, at a height of 1.2 m from the floor of the floor of the technical room 1;

- in fig. 3 shows the experimental results of measurements of the sound pressure spectrum (FFT spectrum) emitted by the ShGTO 14 presented by an Aksipal FTDA-050-3 industrial fan (Russia) mounted in technical room 1 represented by the test room of an acoustic testing laboratory of an industrial enterprise. The measuring microphone was located inside the technical room 1 along the axis of rotation of the fan impeller at a distance of 0.25 m from the surface of its hub;

- in fig. 4 shows the experimental results of measurements of the spectrum of the sound pressure (FFT spectrum) emitted by the ShGTO 14, represented by a piston compressor of the company STAL (Sweden), mounted inside the technical room 1, represented by the compressor-refrigerating station of the testing center of an industrial enterprise. The measurements were carried out inside the technical room 1, at a distance of 3 m from the wall surface of the front part of the compressor housing, at a height of 1.2 m from the floor surface of the technical room 1;

- in fig. 5 shows the schematic diagram of the experimental studies of the own sound vibrations (natural frequencies, acoustic modes of own) of the mass-elastic body of the air volume of the internal cavity with the overall dimensions L⋅B⋅H = 3⋅4⋅5 m of the technical room. one;

- in fig. 6 shows the measurement results given in the information source [4], illustrating the dynamically excited resulting sound field of the technical room 1, characterized by the registered family of acoustic resonant responses of ultrasonic sound waves on the lower eigenfrequency modes f _mA (f _mL , f _mB , f _mH );

- in fig. 7 presents, presented in the information source [4], the three-dimensional ultrasound distribution of longitudinal and transverse acoustic eigenmodes, formed on discrete values of the natural frequencies of sound oscillations f _mL and f _mB , of the investigated cylindrical volumetric air cavity of the technical room 1;

- in fig. 8 is a schematic diagram of the experimental studies of the natural sound vibrations (natural frequencies, natural acoustic modes) of the mass-elastic body of the air volume of the internal cavity with overall dimensions

L⋅B⋅H = 10⋅10⋅4 m technical room 1;

- in fig. 9 shows the results of experimental studies of the frequencies of natural sound vibrations and natural acoustic modes, in the form of discrete values of frequencies of natural sound oscillations of an air volume determined in spatial directions L, B, H of a mass-elastic body of air volume enclosed in an internal air cavity 13 with overall dimensions L, B H of the technical room under study 1;

- in fig. 10 shows schematically the directions and transmission paths of airborne and structural noise emitted by ShGTO 14, mounted in a closed (closed) type of technical room 1;

- in fig. 11 shows plots of sound pressures 15 distributed in the air cavity 13 of the technical room 1, on the excited lower intrinsic (resonant) acoustic modes f _mL (f _1L , f _2L , f _3L ), f _mB (f _1B , f _2B , f _3B ) and f _mH (f _1H , f _2H , f _3H ), which are formed in the directions of its overall length L, width B and height H;

, помещающейся в ограничительных пределах (ограниченной соответствующим габаритом длины L) внутреннего пространства (воздушной полости) 13 технического помещения 1, с помещающейся (совпадающей с ней) половиной длины распространяемой звуковой волны

рабочей доминирующей функциональной частоты низшей гармонической составляющей спектра доминирующей дискретной частоты f_1s, излучаемой ШГТО 14;- in fig. 12.1 schematically depicts a variant design embodiment of the overall size A of the internal space (air cavity) 13 along the length L of the technical room 1, illustrating an example of a full resonant dimensional wave (half-wave) coincidence half of the length of the sound wave of the lowest natural acoustic mode

located in the limiting limits (limited by the corresponding dimension of the length L) of the internal space (air cavity) 13 of the technical room 1, with the half of the length of the propagated sound wave that fits (coincides with it)

the working dominant functional frequency of the lowest harmonic component of the spectrum of the dominant discrete frequency f _1s emitted by GSTO 14;

помещающейся в ограничительных пределах (ограниченной соответствующим габаритом длины L) внутреннего пространства (воздушной полости) 13 технического помещения 1, с половиной длины распространяемой звуковой волны

рабочей доминирующей функциональной частоты низшей гармонической составляющей спектра доминирующей дискретной частоты f_1s, излучаемой ШГТО 14

;- in fig. 12.2 schematically depicts a variant design embodiment of the overall size A of the internal space (air cavity) 13 along the length L of the technical room 1, illustrating an example of the overall wave (half-wave) mismatch of the half-length of the sound wave of the lowest natural acoustic mode

placed in the limiting limits (limited by the corresponding dimension of the length L) of the internal space (air cavity) 13 of the technical room 1, with half the length of the propagated sound wave

the working dominant functional frequency of the lowest harmonic component of the spectrum of the dominant discrete frequency f _1s emitted by the ShSTO 14

;

, помещающейся в ограничительных пределах (ограниченной соответствующим габаритом длины L) внутреннего пространства (воздушной полости) 13 технического помещения 1, с половиной длины распространяемой звуковой волны

рабочей доминирующей функциональной частоты низшей гармонической составляющей спектра доминирующей дискретной частоты f_1s, излучаемой ШГТО 14

;- in fig. 12.3 schematically depicts a variant design embodiment of the overall size A of the internal space (air cavity) 13 along the length L of the technical room 1, illustrating an example of the overall wave (half-wave) mismatch of the half-length of the sound wave of the lowest natural acoustic mode

placed in the limiting limits (limited by the corresponding dimension of the length L) of the internal space (air cavity) 13 of the technical room 1, with half the length of the propagated sound wave

the working dominant functional frequency of the lowest harmonic component of the spectrum of the dominant discrete frequency f _1s emitted by the ShSTO 14

;

, помещающейся в ограничительных пределах (ограниченной соответствующим габаритом ширины В) внутреннего пространства (воздушной полости) 13 технического помещения 1, с помещающейся (совпадающей с ней) половиной длины распространяемой звуковой волны

рабочей доминирующей функциональной частоты низшей гармонической составляющей спектра доминирующей дискретной частоты f_1s, излучаемой ШГТО 14;- in fig. 13.1 schematically depicts a variant design embodiment of the overall size A of the internal space (air cavity) 13 across the width B of the technical room 1, illustrating an example of a full resonant dimensional wave (half-wave) coincidence of half the length of the sound wave of the lowest natural acoustic mode

placed in the limiting limits (limited by the corresponding width of width B) of the internal space (air cavity) 13 of the technical room 1, with the half-length of the propagated sound wave that fits (coincides with it)

the working dominant functional frequency of the lowest harmonic component of the spectrum of the dominant discrete frequency f _1s emitted by GSTO 14;

, помещающейся в ограничительных пределах (ограниченной соответствующим габаритом ширины В) внутреннего пространства (воздушной полости) 13 технического помещения 1, с половиной длины распространяемой звуковой волны

рабочей доминирующей функциональной частоты низшей гармонической составляющей спектра доминирующей дискретной частоты f_1s, излучаемой ШГТО 14

;- in fig. 13.2 schematically depicts a variant design embodiment of the overall size A of the internal space (air cavity) 13 across the width B of the technical room 1, illustrating an example of an overall wave (half-wave) mismatch of half the sound wavelength of a lower natural acoustic mode

placed in the limiting limits (limited by the corresponding width of width B) of the internal space (air cavity) 13 of the technical room 1, with half the length of the propagated sound wave

the working dominant functional frequency of the lowest harmonic component of the spectrum of the dominant discrete frequency f _1s emitted by the ShSTO 14

;

, помещающейся в ограничительных пределах (ограниченной соответствующим габаритом ширины В) внутреннего пространства (воздушной полости) 13 технического помещения 1, с половиной длины распространяемой звуковой волны

рабочей доминирующей функциональной частоты низшей гармонической составляющей спектра доминирующей дискретной частоты f_1s, излучаемой ШГТО 14

;- in fig. 13.3 schematically depicts a variant design embodiment of the overall size A of the internal space (air cavity) 13 across the width B of the technical room 1, illustrating an example of an overall wave (half-wave) mismatch of half the sound wavelength of a lower natural acoustic mode

placed in the limiting limits (limited by the corresponding width of width B) of the internal space (air cavity) 13 of the technical room 1, with half the length of the propagated sound wave

the working dominant functional frequency of the lowest harmonic component of the spectrum of the dominant discrete frequency f _1s emitted by the ShSTO 14

;

, помещающейся в ограничительных пределах (ограниченной соответствующим габаритом высоты Н) внутреннего пространства (воздушной полости) 13 технического помещения 1, с помещающейся (совпадающей с ней) половиной длины распространяемой звуковой волны

рабочей доминирующей функциональной частоты низшей гармонической составляющей спектра доминирующей дискретной частоты f_1s, излучаемой ШГТО 14;- in fig. 14.1 schematically depicts a variant design embodiment of the overall size A of the internal space (air cavity) 13 at the height H of the technical room 1, illustrating an example of a full resonant dimensional wave (half-wave) coincidence of half the length of the sound wave of the lowest natural acoustic mode

placed in the limiting limits (limited by the corresponding height of height H) of the internal space (air cavity) 13 of the technical room 1, with the half of the length of the propagated sound wave that fits (coincides with it)

the working dominant functional frequency of the lowest harmonic component of the spectrum of the dominant discrete frequency f _1s emitted by GSTO 14;

, помещающейся в ограничительных пределах (ограниченной соответствующим габаритом высоты Н) внутреннего пространства (воздушной полости) 13 технического помещения 1, с половиной длины распространяемой звуковой волны

рабочей доминирующей функциональной частоты низшей гармонической составляющей спектра доминирующей дискретной частоты f_1s, излучаемой ШГТО 14

;- in fig. 14.2 schematically depicts a variant design embodiment of the overall size A of the internal space (air cavity) 13 at the height H of the technical room 1, illustrating an example of the overall wave (half-wave) mismatch of half the sound wavelength of the lower natural acoustic mode

placed in the limiting limits (limited by the appropriate dimension of height H) of the internal space (air cavity) 13 of the technical room 1, with half the length of the propagated sound wave

the working dominant functional frequency of the lowest harmonic component of the spectrum of the dominant discrete frequency f _1s emitted by the ShSTO 14

;

, помещающейся в ограничительных пределах (ограниченной соответствующим габаритом высоты Н) внутреннего пространства (воздушной полости) 13 технического помещения 1, с половиной длины распространяемой звуковой волны

рабочей доминирующей функциональной частоты низшей гармонической составляющей спектра доминирующей дискретной частоты f_1s, излучаемой ШГТО 14

;- in fig. 14.3 schematically depicts a variant design embodiment of the overall size A of the internal space (air cavity) 13 at the height H of the technical room 1, illustrating an example of the overall wave (half-wave) mismatch of half the sound wavelength of the lower natural acoustic mode

placed in the limiting limits (limited by the appropriate dimension of height H) of the internal space (air cavity) 13 of the technical room 1, with half the length of the propagated sound wave

the working dominant functional frequency of the lowest harmonic component of the spectrum of the dominant discrete frequency f _1s emitted by the ShSTO 14

;

- in fig. 15 schematically shows a concretized example of the variant execution of a low-noise technical room 1, presented in the form of an ETPZT, with the ShGTO 14 located in it, represented by a power electrical transformer, characterized by low-frequency acoustic radiation dominant in the spectrum, manifested on multiple discrete components f _1s = 100 Hz, f _2s = 200 Hz, f _3s = 300 Hz (see also Fig. 1 and 2);

- in fig. 16.1 presents the results of an experimental determination of the change in ultrasonic sounding at a pronounced energy-intensive first intrinsic acoustic mode (λ _1L ) with a discrete value of the natural frequency of sound vibrations f _1L = 43 Hz of the mass-elastic body of air volume enclosed in an internal three-dimensional air cavity 13 of the technical room 1 under study rigid sound-reflecting walls (without surface sound-absorbing linings), in the direction of the overall dimension of the length L of the air cavity 13, equal to 4 m;

- in fig. 16.2 presents the results of an experimental determination of the change in ultrasonic sounding at a pronounced energy-intensive first intrinsic acoustic mode (λ _1B ) with a discrete value of the natural frequency of sound vibrations f _1B = 86 Hz of the mass-elastic body of air volume enclosed in an internal three-dimensional air cavity 13 of the technical room under study 1 rigid sound-reflecting walls (without surface sound-absorbing linings), in the direction of the overall size of the width In the air cavity 13, equal to 2 m;

- in fig. 16.3 presents the results of an experimental determination of the change in ultrasonic sounding at a pronounced energy-intensive first intrinsic acoustic mode (λ _1L ) with a discrete value of the natural frequency of sound vibrations f _1L = 36 Hz rigid sound-reflecting walls (without surface sound-absorbing linings), in the direction of the overall dimension of the length L of the air cavity 13, equal to 5 m;

- in fig. 16.4 presents the results of an experimental determination of the change in ultrasonic sounding at the third acoustic mode (λ _3B ) with a discrete value of the natural frequency of sound oscillations f _3B = 129 Hz of the mass-elastic body of air volume enclosed in an internal three-dimensional air cavity 13 of the technical room 1 under study, equipped with rigid sound reflecting walls (without surface sound-absorbing linings), in the direction of the overall size of the width In the air cavity 13, equal to 4 m;

внутренней трехмерной воздушной полости 13 технического помещения 1 на дискретных значениях собственных частот звуковых колебаний f_mA (f_mL, f_mB, f_mH), составленных по габаритному размеру А (длины L, ширины В, высоты Н) воздушной полости 13, при варианте нахождения (попадания) габаритного размера A (L, В, Н) воздушной полости 13 технического помещения 1 в области значений зоны критического диапазона (критических диапазонов) 4 недопустимых (нежелательных) волновых совпадений Δλ_mA (Δλ_mL, Δλ_mB, Δλ_mH), обеспечивающего эффективное рассогласование физического процесса кратных совпадений полудлин звуковых волн

излучаемых ШГТО 14, с габаритным размером A (L, В или Н) воздушной полости 13 технического помещения 1;- in fig. 17 presents illustrative examples of the formation of a sound pressure pattern 15, excited by lower eigenmodes (resonant) acoustic modes.

internal three-dimensional air cavity 13 of the technical room 1 at discrete values of the natural frequencies of sound oscillations f _mA (f _mL , f _mB , f _mH ) made up according to the overall dimension A (length L, width B, height H) of the air cavity 13, if it is found (hits) overall dimensions A (L, B, H) of the air cavity 13 of the technical room 1 in the range of values of the critical range (critical ranges) 4 unacceptable (unwanted) wave coincidences Δλ _mA (Δλ _mL , Δλ _mB , Δλ _mH ) providing effective disagreement is physical process of multiple coincidences of half-lengths of sound waves

emitted by ShGTO 14, with overall dimensions A (L, B or H) of the air cavity 13 of the technical room 1;

внутренней трехмерной воздушной полости 13 технического помещения 1 на дискретных значениях собственных частот звуковых колебаний f_mA (f_mL, f_mB, f_mH), составленных по габаритному размеру А (длины L, ширины В, высоты Н) воздушной полости 13, при варианте нахождения габаритного размера A (L, В, Н) воздушной полости 13 технического помещения 1 вне областей значений зоны критического диапазона (критических диапазонов) 4 недопустимых (нежелательных) волновых совпадений Δλ_mA (Δλ_mL, Δλ_mB, Δλ_mH), обеспечивающего эффективное рассогласование физического процесса кратных совпадений полудлин звуковых волн

излучаемых ШГТО 14, с габаритным размером A (L, В или Н) воздушной полости 13 технического помещения 1;- in fig. 18 illustrative examples of the formation of a sound pressure pattern 15, excited by lower eigenmodes (resonant) acoustic modes are presented.

internal three-dimensional air cavity 13 of the technical room 1 at discrete values of the natural frequencies of sound oscillations f _mA (f _mL , f _mB , f _mH ) made up according to the overall dimension A (length L, width B, height H) of the air cavity 13, if it is found overall dimension A (L, B, H) of the air cavity 13 the technical room 1 outside the ranges of critical band area (critical ranges) 4 impermissible (unwanted) wave matches _{Δλ mA (Δλ mL, Δλ mB} , Δλ mH), providing effective mismatch physical proce ssa multiple coincidences of half-lengths of sound waves

emitted by ShGTO 14, with overall dimensions A (L, B or H) of the air cavity 13 of the technical room 1;

внутренней трехмерной воздушной полости 13 технического помещения 1 на дискретных значениях собственных частот звуковых колебаний f_mA (f_mL, f_mB, f_mH), составленных по габаритному размеру А (длины L, ширины В, высоты Н) воздушной полости 13, при варианте нахождения габаритного размера A (L, В, Н) воздушной полости 13 технического помещения 1 вне областей значений зоны критического диапазона (критических диапазонов) 4 недопустимых (нежелательных) волновых совпадений Δλ_mA (Δλ_mL, Δλ_mB, Δλ_mH), обеспечивающего эффективное рассогласование физического процесса кратных совпадений полудлин звуковых волн

излучаемых ШГТО 14, с габаритным размером A (L, В или Н) воздушной полости 13 технического помещения 1;- in fig. 19 presents illustrative examples of the formation of a sound pressure pattern 15, excited by lower eigenmodes (resonant) acoustic modes.

internal three-dimensional air cavity 13 of the technical room 1 at discrete values of the natural frequencies of sound oscillations f _mA (f _mL , f _mB , f _mH ) made up according to the overall dimension A (length L, width B, height H) of the air cavity 13, if it is found overall dimension A (L, B, H) of the air cavity 13 the technical room 1 outside the ranges of critical band area (critical ranges) 4 impermissible (unwanted) wave matches _{Δλ mA (Δλ mL, Δλ mB} , Δλ mH), providing effective mismatch physical proce ssa multiple coincidences of half-lengths of sound waves

emitted by ShGTO 14, with overall dimensions A (L, B or H) of the air cavity 13 of the technical room 1;

. Заштрихованные области зон критических диапазонов (поз. 4) указывают на недопустимые (нежелательные) резонансные волновые совпадения полудлин звуковых волн

и

;- in fig. 20 presents illustrative examples depicting possible variant (in overall size A) designs of a technical room 1 with different overall dimensions A of an internal three-dimensional air cavity 13 (length L and width B) in which lower intrinsic acoustic modes are formed (λ _mL , λ _mB ) air cavity 13 technical premises 1, characterized by the plots of sound pressure lower intrinsic acoustic modes λ _mA at discrete values of the natural frequencies of sound vibrations f _mL , with the fit in the air Aural cavity 13 in the direction of its overall length L with a different integer n _vs = 1, 2, 3 half-lengths of sound waves

. Shaded areas of zones of critical ranges (pos. 4) indicate unacceptable (undesirable) resonant wave coincidences of half-lengths of sound waves

and

;

- in fig. 21 is a diagram of the energy addition (subtraction) of two logarithmic values of the ultrasound in dB.

Digital positions and letter symbols on the presented figures indicate:

1 - technical room (building), then - technical room 1;

2 - speaker (electrodynamic loudspeaker), then - speaker 2;

3 - measuring microphone, measuring microphone grille (hereinafter - measuring microphone 3);

), звуковых волн, излучаемых ШГТО 14, смонтированном в техническом помещении 1, с длинами λ_mA (полудлинами

) собственных акустических мод, формирующихся в внутренней трехмерной воздушной полости 13, характеризуемой габаритными размерами A (L, B, H), (далее - области значений критических диапазонов Δλ_mA);4 - the range of values of the critical ranges Δλ _{mA of} unacceptable (undesirable) wave coincidences, providing an effective mismatch of the physical process of multiple resonant coincidences of lengths λ _mS

), sound waves emitted by ShGTO 14, mounted in the technical room 1, with lengths λ _mA (half lengths

a) of own acoustic modes formed in the internal three-dimensional air cavity 13, characterized by overall dimensions A (L, B, H), (hereinafter referred to as the ranges of values of the critical ranges Δλ _mA );

5 - ceiling (ceiling) of the technical room 1 (hereinafter - ceiling 5);

6 - the floor of the technical room 1 (hereinafter - floor 6);

7 - side walls of the technical room 1 (hereinafter - the side walls 7);

8 - the front wall of the technical room 1 (hereinafter - the front wall 8);

9 — front door doorway 8 (hereinafter, doorway 9);

10 - the entrance door of the doorway 9 (hereinafter - the entrance door 10);

11 - the back wall of the technical room 1 (hereinafter - the back wall 11);

12 - supply and exhaust ventilation openings of the technical room 1 (hereinafter referred to as ventilation openings 12);

13 - internal three-dimensional air cavity of the technical room 1, bounded by the enclosing surfaces of the ceiling 5, floor 6, side walls 7 and the closed entrance door 10 (hereinafter - the air cavity 13);

14 - noise-generating technical object (hereinafter - STEP 14);

15 - sound pressure diagrams forming on the lowest eigen (resonant) acoustic modes of the air cavity 13, excited by the sound radiation of the ShGTO 14, composed in directions of overall dimensions A (length L, width B and height H) of the air cavity 13 (hereinafter - sound pressure diagrams on lower natural (resonant) acoustic modes 15);

Accepted letter designations of composite structural elements and physical parameters used for vibro-acoustic fields of a technical room 1:

A - one of the basic dimensional parameters (L, B, H), characterizing the dimensions of the internal three-dimensional space of the air cavity 13 of the technical room 1;

L is the overall length of the three-dimensional internal air cavity 13 of the technical room 1;

B - the overall width of the three-dimensional internal air cavity 13 of the technical room 1;

H is the overall height of the three-dimensional internal air cavity 13 of the technical room 1;

Р - sound pressure, N / m ² (sound pressure level, dB);

P _mA (P _mL , P _mB , P _mH ) is the sound pressure on the excited intrinsic (resonant) acoustic modes of the internal three-dimensional air cavity 13, formed in the spatial directions of its overall parameters A (L, B, H), N / m ² dB);

P _1L , P _2L , P _3L - sound pressure on the excited three lower proper (resonant) acoustic modes of the internal three-dimensional air cavity 13, formed in the spatial directions of the dimensional parameters of its length L, N / m ² (dB)

P _1B , P _2B , P _3B - sound pressure on the excited three lower own (resonant) acoustic modes of the internal three-dimensional air cavity 13, formed in the spatial directions of the dimensional parameters of its width B, N / m ² (dB)

P _1H , P _2H , P _3H - sound pressure on the excited three lower own (resonant) acoustic modes of the internal three-dimensional air cavity 13, formed in the spatial directions of the dimensional parameters of its height H, N / m ² (dB);

f is the frequency of sound vibrations, Hz (s ^-1 );

f _c - industrial frequency of the AC network, Hz;

f _mA (f _mL , f _mB , f _mH ) are discrete values of the natural frequencies of sound vibrations on the natural acoustic modes of a mass-elastic body of air volume, with sound wave lengths λ _mA (λ _mL , λ _mB , λ _mH ), which are formed in three-dimensional air cavity 13 technical room 1, in the direction of the overall parameters A (L, B, H), Hz;

f _1L , f _2L , f _3L - discrete values of the natural frequencies of sound vibrations in the first three lower acoustic modes of the mass-elastic body of air volume, with sound wavelengths λ _mL (λ _1L , λ _2L , λ _3L ), which are formed in the internal three-dimensional the air cavity 13, in the direction of the overall length L, Hz;

f _1B , f _2B , f _3B - discrete values of the natural frequencies of sound vibrations in the first three lower natural acoustic modes of the mass-elastic body of air volume, with sound wavelengths λ _mB (λ _1B , λ _2B , λ _3B ), formed in the internal three the air cavity 13, in the direction of the overall width, Hz;

f _1H , f _2H , f _3H - discrete values of the natural frequencies of sound vibrations in the first three lower acoustic modes of the mass-elastic body of air volume, with sound wavelengths λ _mH (λ _1H , λ _2H , λ _3H ), which are formed in the internal three the air cavity 13, in the direction of the overall height H, Hz;

f _ms - working dominant functional frequency of sound radiation SHGTO 14, Hz;

(f _1s , f _2s , f _3s ) - discrete values of the operating dominant functional frequencies of sound vibrations, represented by three multiple lower harmonic components of the spectrum of sound radiation of ShGTO 14, Hz;

и

), на величину 15 дБ, Гц;f _a , fb - values of the boundary frequencies of resonant sound vibrations of the mass-elastic body of the air volume of the internal three-dimensional air cavity 13, at which the amplitude values of the sound pressure (sound pressure levels) are reduced at the frequency-wave mismatch of the interacting sound radiation with frequencies f _mA and f _ms , and wavelengths λ _mA and λ _ms (half wavelengths

and

), by the value of 15 dB, Hz;

Δf is the width of the frequency band, at the boundaries of which the maximum value of the amplitude of sound pressure in it is reduced by 15 dB, Hz;

λ - sound wavelength, m;

λ _ms - the length of the sound wave of the working dominant functional frequency f _{ms of the} sound radiation of the ShGTO 14 at a given steady-state operating mode n _s , m;

_{(λ 1s, λ 2s, λ} 3s) - the length of the sound waves of three multiple dominant harmonics of the frequency _{(f 1s, f 2s, f} 3s) Working dominant functional frequency f _ms sound radiation SHGTO 14 at a predetermined steady operational mode n _s, m;

λ _mA (λ _mL , λ _mB , λ _mH ) are the sound wavelengths on the lower proper acoustic modes represented by the intrinsic acoustic oscillations of the mass-elastic body of the air volume of the internal three-dimensional air cavity 13 of the technical room 1, m;

) звуковых волн, излучаемых ШГТО 14, смонтированном в техническом помещении 1, с длинами λ_mA (полудлинами

) собственных акустических мод, формирующихся в внутренней трехмерной воздушной полости 13, характеризуемой габаритными размерами A (L, В, Н);Δλ _mA (Δλ _mL , Δλ _mB , Δλ _mH ) are the ranges of values of the critical ranges of unacceptable (undesirable) wave resonance coincidences, ensuring effective mismatch (preventing the development) of the physical process of multiple resonant coincidences of lengths λ _mS (half-length

) sound waves emitted by ShGTO 14, mounted in the technical room 1, with lengths λ _mA (half-lengths

a) own acoustic modes, which are formed in the internal three-dimensional air cavity 13, characterized by the dimensions A (L, B, H);

) звуковых волн, излучаемых ШГТО 14, смонтированном в техническом помещении 1, с длинами λ_mA (полудлинами

) первых трех низших собственных акустических мод, формирующихся в внутренней трехмерной воздушной полости 13, характеризуемой габаритными размерами A (L, В, Н);Δλ _{1A, 2A} Δλ, Δλ _3A - field values of the critical bands invalid (unwanted) resonant wave coincidence ensure effective mismatch (prevention of) physical process multiple coincidence resonance wavelength λ _mS (half-lengths

) sound waves emitted by ShGTO 14, mounted in the technical room 1, with lengths λ _mA (half-lengths

a) the first three lower proper acoustic modes, which are formed in the internal three-dimensional air cavity 13, characterized by the overall dimensions A (L, B, H);

λ _{mA20 ° C} - sound wavelengths on the lower proper acoustic modes, represented by the own acoustic oscillations of the mass-elastic body of the air volume enclosed inside the internal three-dimensional air cavity 13, with the accepted basic value of air temperature in it equal to + 20 ° C, m;

λ _{mAt ° C} is the sound wavelengths on the lower proper acoustic modes, represented by the intrinsic acoustic oscillations of the mass-elastic body of the air volume enclosed within the internal three-dimensional air cavity 13, with the operational stabilized air temperature value t ° C, m;

n _s is a given steady-state high-speed operational mode of operation of the ShGTO 14, characterized by sound radiation containing in the spectrum prominent working dominant functional frequencies of sound vibrations f _ms , min ^-1 , s ^-1 ;

рабочей доминирующей функциональной частоты f_ms звукового излучения ШГТО 14, укладывающихся в ограничительных пределах габаритного параметра А, характеризующего габаритные размеры внутренней трехмерной воздушной полости 13 технического помещения 1 (L, В, Н);n _vs is an integer (natural number) half-lengths of sound waves

the working dominant functional frequency f _{ms of the} sound radiation of the ShGTO 14, which falls within the limiting limits of the overall parameter A, which characterizes the dimensions of the internal three-dimensional air cavity 13 of the technical room 1 (L, B, H);

m is the ordinal number of the multiple eigenacoustic mode (f _mA , λ _mA ) of the sound oscillations of the mass-elastic body of the air volume of the internal three-dimensional air cavity 13, the number of the multiple harmonic of the working dominant functional frequency f _ms and the sound wavelength λ _{ms of the} sound radiation of the ShGTO 14, expressed by integer number of natural number;

m _L is the ordinal number of the own acoustic mode of sound vibrations of the mass-elastic body of the air volume of the internal three-dimensional air cavity 13 of the technical room 1, which is formed in the direction of its overall length L, expressed by an integer number of the natural series (m = 1, 2, 3 ...);

m _B is the ordinal number of the acoustic mode of sound oscillations of the mass-elastic body of the air volume of the internal three-dimensional air cavity 13 of the technical room 1, which is formed in the direction of its overall width B, expressed by an integer number of the natural row (m = 1, 2, 3 ...);

m _H is the ordinal number of the acoustic mode of sound oscillations of the mass-elastic body of the air volume of the internal three-dimensional air cavity 13 of the technical room 1, formed in the direction of its overall height H, expressed by an integer number of the natural series (m = 1, 2, 3 ...)

c is the speed of propagation of sound waves in the air environment of the internal space of the internal three-dimensional air cavity 13 of the technical room 1, m / s;

c (t) is the speed of sound waves in m / s distributed in the air environment of the internal space of the internal three-dimensional air cavity 13 of the technical room 1, at its established operating temperature conditions at t ° C;

t ° C is the temperature of the air in the internal three-dimensional air cavity 13 of the technical room 1, ° C;

Δt ° C is the allowable (recommended) operating operational range for changing the air temperature in the internal three-dimensional air cavity 13 of the technical room 1, ° C;

, характеризуемых соответствующими дискретными значениями собственных частот звуковых колебаний (f_mL, f_mB, f_mH), удовлетворяющими условиям предотвращения (эффективного ослабления) развития физического процесса резонансного усиления излучения звуковых колебаний в воздушной полости 13, в которой смонтирован ШГТО 14, производящий звуковое излучение с заданными дискретными значениями рабочих доминирующих функциональных частот гармонических составляющих спектра звукового излучения f_ms (f_1s, f_2s, f_3s), характеризующихся длинами λ_ms (λ_1s, λ_2s, λ_3s) (полудлинами

) звуковых волн;K _mA (K _mL , K _mB , K _mH ) are the multiplicity coefficients of the established ratios of the dimensions of the dimensions A of the internal three-dimensional air cavity 13 (its length L, width B and height H), with corresponding numerical values of their own half lengths within their limited spatial directions sound waves on the lower proper acoustic modes, represented by the intrinsic acoustic oscillations of a mass-elastic body of air volume contained within the air cavity 13, -

characterized by corresponding discrete values of sound vibration eigenfrequencies (f _mL , f _mB , f _mH ) satisfying the conditions for preventing (effective attenuation) the development of the physical process of resonant amplification of sound vibrations in an air cavity 13, in which SHGTO 14 is mounted, producing sound radiation with given discrete values of the working dominant functional frequencies of the harmonic components of the spectrum of sound radiation f _ms (f _1s , f _2s , f _3s ), characterized by lengths λ _ms (λ _1s , λ _2s , λ _{3 s} ) (half length

a) sound waves;

K _t is the reduced temperature coefficient of sound speed correction c (t) and sound wavelengths λ _mA and λ _ms , emitted by the ShGTO 14 and propagating in the internal three-dimensional air cavity 13, in a given steady-state operating operational range Δt ° C, changes in air temperature in the internal space air cavity 13 technical room 1;

T is the period of wave (sound) oscillations, s;

ϕ — phase of harmonic wave oscillations, radians;

α _N - normal sound absorption coefficient, sr. units (%);

α _rev - reverberation coefficient of sound absorption, in usl. units (%);

A _eq is the area of equivalent sound absorption, m ² ;

t _rev is the reverberation time, s;

x is the ratio of the specific heats of gas at constant pressure and volume (for air, which is mainly diatomic gas, x = 1.40);

p - static atmospheric (barometric) pressure, N / m ² ;

Р - sound pressure, N / m ² (sound pressure level, dB);

ρ - air density, kg / m ³ ;

V _μ - molar volume, m ³ ;

R _r is the molar gas constant (srv);

T _c is thermodynamic temperature, K;

Q is the quality factor of the resonant oscillating system frequency response (standard units);

Q _R - the quality factor of the frequency characteristics of the acoustic resonator (standard units);

Q _a - the quality factor of its own acoustic resonance of the internal three-dimensional air cavity 13 of the technical room 1 (standard units).

ICE - internal combustion engine;

ShSTO - noise-generating technical object 14;

ETPZT - closed type electrical transformer substation;

SPL - sound pressure level, dB.

Terminology used in the description of the application for invention

Acoustic resonators - frequency tuned noise suppressing devices (Helmholtz resonators R ^III , quarter-wave R ^I and half-wave R ^II acoustic resonators R) are technical devices intended for dissipative absorption (dissipation, damping) of sound (acoustic) energy distributed in the gas-dynamic (aerodynamic) the system to which they are connected; The most effective use of acoustic resonators R refers to the absorption of resonant sound vibrations in the outgoing frequency components in the noise emission spectra of the gas-dynamic (aerodynamic) system.

Wave interference is the physical process of addition in unlimited space or in a limited waveguide of two or more waves having the same oscillation periods T, as a result of which the amplitude value of the resulting wave increases or decreases in different zones of unlimited space or limited waveguide space depending on the phase relationships oscillations ϕ of the developing (interacting) waves, thus forming non-uniform spatial distributions of the amplitude of the rushing wave.

Coherence is a coordinated flow of several oscillatory or wave processes with identical frequencies over time, which is observed when they are added together. Oscillations are called coherent, if the difference of their phases remains constant in time and the sum determines the amplitude of the total oscillation.

The beats of sound (acoustic oscillations) are the result of the interference summation of two harmonic sound waves with close frequencies, manifested as alternating amplitude maxima and minima.

A diffuse (reverberation) sound field is a sound field that forms in enclosed volumes (enclosed spaces) limited by rigid sound reflecting walls, at each point of which the sound pressure level is the same.

Reverberation is a physical phenomenon of radiation, propagation, reflection and attenuation of sound waves as a result of which, after the source ceases to emit sound, the processes of propagation, reflection and attenuation of sound occur for some time, characterized by the “reverberation time” parameter.

The reverberation time is the time interval in seconds, measured in a closed confined space, after turning off the sound source, during which the sound pressure level of a given radiation frequency decreases by 60 dB (1000 times).

Reverberation acoustic chamber - measuring technical room (measuring laboratory-bench setup), in which at least 98% of the radiated acoustic energy source is reflected in the opposite direction to the sound radiation source located in this room, from the walls, floor and ceiling that form it hard sound reflecting material.

Sound insulation is a term used to denote three technical characteristics and refers directly to the acoustic structure itself, the integrated physical process of absorption and reflection of sound waves by the acoustic structure and to quantify the change (attenuation) of the transmission of acoustic radiation (numerical change of the parameters of the physical soundproofing process) introduced used acoustic design; is a measure of sound insulation by a partition, wall or panel expressed in dB; sound insulation is equal to the decimal logarithm of the ratio of the intensity of the falling (P _pad ) and transmitted (P _ol ) through the partition of sound waves or the difference of their levels in dB.

Sound absorption is the physical process of weakening part of the energy of sound vibrations distributed in the porous structure of a sound-absorbing material, with the resulting irreversible dissipative conversion of sound energy into thermal energy dissipated exclusively by the medium of the porous structure in which the sound wave propagates; characterized by sound absorption coefficient (normal α _N , reverberation α _rev ) and / or equivalent sound absorption area A _eq .

The reverberation sound absorption coefficient (α _rev ) is the ratio of the energy of a diffuse sound field absorbed by the surface of a material sample under investigation (a full-scale part under study) to the energy of a diffuse sound field falling on it; is determined by the changeable recorded reverberation time t _rev in the working cavity of the measuring reverberation chamber based on the results of placing the material sample under study (the full-scale part under study) in its cavity.

Sound-absorbing material - structural acoustic material of fibrous and / or open-cell porous air-blown nature, characterized by a reverberation sound absorption coefficient α _rev not less than 0.2

A sound-reflecting material is a structural material, represented by a dense solid air-blown structure of a substance, characterized by a reverberation sound absorption coefficient α _rev not exceeding 0.1.

Sound transparency is a physical property of the structures (individual structural elements - plates, shells, films) to transmit a sound wave without significantly attenuating its energy (without significant reflection in the opposite direction to propagation from the radiation source). Quantitatively, sound transparency is characterized by a sound transmission coefficient. The design is considered to be sound-transparent if the attenuation of the transmission of sound energy introduced by it does not exceed 10%.

The natural (resonant) frequency f _m is the oscillation frequency at which resonance occurs (in this case, the frequency of sound oscillations f _m at which an acoustic resonance is observed, characterized by a significant amplification of sound pressure amplitudes).

Own (resonant) acoustic modes - a characteristic of the vibro-acoustic properties of a mechanical or gas-dynamic system, directly related to its own (resonant) frequency of its oscillations f _m ; site (resonance) acoustic mode illustrates the type (three-dimensional shape) of the acoustic vibrations of the system at its natural (resonant) frequency f _m oscillations, is realized at f _m systems coincidence natural oscillation frequencies with the frequencies of its forced vibrations f _s (frequencies external dynamic excitation f _s) .

The lowest natural acoustic modes are the spatial forms of acoustic oscillations at the natural (resonant) frequencies f _m for the values m = 1, 2, 3.

The Q of the frequency response of the resonator oscillatory system Q is a quantitative characteristic of the resonant properties of the oscillatory system, numerically equal to the ratio of the natural frequency of the resonant system to the width of the frequency band, at the borders of which the system energy with forced oscillations is 2 times less than the energy at the resonant frequency.

The Q of the frequency response of the acoustic resonator Q _R is a parametric characteristic of the acoustic resonator R, indicating internal dissipative losses arising both in the composite structures (elements) of the acoustic resonator R and due to external energy losses directly related to the process of sound emission into the environment, which also consumes a certain part of the vibrational energy of the acoustic resonator R.

The quality factor of own acoustic resonance inside the three-dimensional air cavity technical premises Q _a - a quantitative characteristic of the resonance properties of the oscillating system, represented as a weight and an elastic body of the air volume inside the three-dimensional air cavity 13 technical room 1, which is numerically equal to the ratio own (resonant) frequency sound oscillations f _mA to the bandwidth Δf, at the boundaries of which the maximum value of the sound pressure level is reduced by 15 dB.

The sound (acoustic) field of the technical room is the resulting steady-state distribution of the energy of the incident and reflected sound waves, with realizable accompanying physical processes of its propagation, amplification and absorption in the three-dimensional air volume of the technical room limited by rigid wall structures. One of the basic components of the acoustic field of the technical room 1, considered in the technical solutions of the application for the invention, is the expression (1):

where c is the speed of propagation of sound waves in the air environment of the internal space of the internal three-dimensional air cavity 13 of the technical room 1, m / s (c = 344.057 m / s at + 20 ° C);

L is the overall length of the internal space of the air cavity 13 of the technical room 1, m;

B - overall width of the internal space of the air cavity 13 of the technical room 1, m;

H - the overall height of the internal space of the air cavity 13 technical room 1, m;

m _L is the ordinal number of the acoustic mode of sound oscillations of the mass-elastic body of the air volume of the internal three-dimensional air cavity 13 of the technical room 1 in the direction of its overall length L, expressed by an integer number of the natural series (m = 1, 2, 3 ...)

m _B is the ordinal number of the own acoustic mode of sound oscillations of the mass-elastic body of the air volume of the internal three-dimensional air cavity 13 of the technical room 1 in the direction of its overall width B, expressed by an integer number of the natural number (m = 1, 2, 3 ...);

m _H is the ordinal number of the acoustic mode of sound oscillations of the mass-elastic body of the air volume of the internal three-dimensional air cavity 13 of the technical room 1 in the direction of its overall height H, expressed by an integer number of the natural series (m = 1, 2, 3 ...)

The temperature field of the technical room is a set of temperature values in the spatial domain of the internal three-dimensional air cavity 13 of the technical room 1 at a given time.

The essential features of the proposed technical solution are illustrated by figures 1 ... 21.

, излучаемых ШГТО 14, смонтированным во внутренней трехмерной воздушной полости 13 габаритным размером A (L, В, Н), с полудлинами звуковых волн

низших собственных акустических мод, представленных собственными акустическими колебаниями массо-упругого тела воздушного объема, заключенного внутри внутренней трехмерной воздушной полости 13 технического помещения 1. Таким образом, осуществляется исключение (эффективное ослабление) возникновения негативной ответной динамической колебательной реакции, в виде резонансного виброакустического отклика массо-упругого тела воздушного объема, на воздействующее на него (возбуждающее его) звуковое излучение от ШГТО 14, которое реализуется за счет соответствующей степени рассогласования резонансных совпадений их частотно-модальных характеристик. При таких физических условиях осуществляется заданное эффективное рассогласование (устранение) волновых акустических резонансных совпадений что, в свою очередь, вызывает полное исключение (эффективное ослабление) развития физического процесса резонансного динамического возбуждения низших собственных акустических мод, характеризуемых дискретными значениями собственных частот звуковых колебаний f_mA-f_mL (f_1L, f_2L, f_3L), f_mB (f_1B, f_2B, f_3B) и f_mH (f_1H, f_2H, f_3H), характеризуемых соответствующими длинами собственных звуковых волн λ_mA-λ_mL (λ_1L, λ_2L, λ_3L), λ_mB (λ_1B, λ_2B, λ_3B) и λ_mH (λ_1H, λ_2Н, λ_3H) и соответствующими им полудлинами собственных звуковых волн

и

колеблющегося массо-упругого тела воздушного объема, заключенного во внутренней трехмерной воздушной полости 13 технического помещения 1, с дискретными значениями рабочих доминирующих функциональных частот звуковых колебаний f_ms, представленных, по крайней мере (в первую очередь), тремя низшими гармоническими составляющими спектра звукового излучения ШГТО 14, характеризуемых кратными длинами звуковых волн λ_ms-λ_1s, λ_2s и λ_3s. Таким образом, ввиду осуществляемого условия предотвращения (эффективного ослабления) развития физического процесса резонансного усиления звукового излучения, реализуются соответствующие эффекты уменьшения уровней звукового излучения (шума) как внутри технического помещения 1, так и вне его - в сопредельных помещениях, входящих в состав строительного здания, или в примыкающем к строительному зданию открытом окружающем пространстве, в виде воздушного и структурного шума, передающегося через недостаточно высокую (неудовлетворительную) звукоизолирующую способность стеновых прегородок (поз. 7 и 5), элементов дверного проема и входной двери (поз. 9 и 10), вентиляционных проемов (поз. 12), как это иллюстрируется, в частности, на схемах фиг. 10 и 11. Также имеет место предотвращение (исключение) процесса возникновения биений взаимодействующих акустических сигналов (звуковых волн) с близкими значениями частот звуковых колебаний f_ms и f_mA.Schematically shown in FIG. 10 technical room 1, contains rigid supporting fencing elements made in the form of side walls 7, front wall 8, rear wall 11, ceiling 5, floor 6, doorway 9 with closed entrance door 10 and open ventilation openings 12. Internal three-dimensional air cavity 13 of the technical room 1 is represented by a hollow rectangular cylinder of the hollow rectangular parallelepiped type with overall dimensions A (L, B, H), in which SHGTO 14 is mounted, producing acoustic (noise) radiation, in the form of propagated sound waves , Qualifying noise picture corresponding arrows of said figure. At the same time, during operation of ShGTO 14, thermal energy is generated, which also spreads in the internal three-dimensional air cavity 13 of the technical room 1. Thus, in the internal three-dimensional air cavity 13, corresponding sound and temperature fields are formed (spatially distributed). Rigid carrier enclosing sound-reflecting elements of the technical room 1 can be represented by prefabricated large-panel (reinforced concrete, frame-metal), large-block monolithic or hand-made brickwork constructive-technological designs. ShGTO 14 (for example, reciprocating internal combustion engine, mechanical gearbox, fan installation, electric generator, power transformer, blower machine, axial or centrifugal type exhaust fan, piston or centrifugal pump, piston compressor (or several simultaneously operating in technical room 1 ShGTO 14), as a rule , operates on a given constant (technical conditions of operation) steady-state constant speed (load) operating mode n _s . Specific values of dimensions A The internal three-dimensional air cavity 13 (L, B, H) of the technical room 1 predetermines the physical characteristics of the mass-elastic body of air volume, characterized by certain values of the lowest natural acoustic modes, formed on the corresponding discrete values of the natural (resonant) frequencies of sound vibrations f _mA (f _mL , f _mB , f _mH ), with corresponding sound wavelengths λ _mA (λ _mL , λ _mB , λ _mH ), excited as a result of the implementation of the physical process of dynamic excitation and the response dynamic oscillation the flax reaction of an elastic air medium as a result of the propagation in it of sound waves represented as natural acoustic oscillations of a mass-elastic body of air volume enclosed within an internal three-dimensional air cavity 13 of a technical room 1. A distinctive feature of the proposed technical device presented as a low-noise technical room 1 , is that the overall dimensions A (L, B, H) of the internal three-dimensional air cavity 13 of the technical room 1 are selected in such a way that be prevented (effectively weakened) development of the physical process of resonance amplification of acoustic radiation and eliminates the process of occurrence of beats interacting acoustic signals (sound waves) with close values of frequency of acoustic oscillations f _ms and f _mA due to realization of sufficient size field values of the critical bands invalid (unwanted) resonance wave (frequency-model) coincidences 4, providing a sufficient degree of effective mismatch (prevention) of multiple coincidence tions half-lengths of sound waves

emitted by ShGTO 14, mounted in the internal three-dimensional air cavity 13 with overall dimensions A (L, B, H), with half-lengths of sound waves

lower eigen acoustic modes represented by eigen acoustic oscillations of a mass-elastic body of air volume enclosed within an internal three-dimensional air cavity 13 of a technical room 1. Thus, the exclusion (effective attenuation) of the occurrence of a negative response dynamic vibrational response, in the form of a resonant vibroacoustic response of the mass the elastic body of the air volume, the sound radiation acting on it (exciting it) from the ShGTO 14, which is realized due to the corresponding degree of mismatch of the resonant coincidences of their frequency-modal characteristics. Under such physical conditions, a given effective mismatch (elimination) of the acoustic wave resonance coincidences takes place, which, in turn, causes the complete elimination (effective attenuation) of the development of the physical process of resonant dynamic excitation of lower natural acoustic modes characterized by discrete values of the natural frequencies of sound vibrations f _mA -f _mL (f _1L , f _2L , f _3L ), f _mB (f _1B , f _2B , f _3B ) and f _mH (f _1H , f _2H , f _3H ), characterized by the respective own sound wavelengths λ _mA -λ _mL ( λ _1L , λ _2L , λ _{3 L} ), λ _mB (λ _1B , λ _2B , λ _3B ) and λ _mH (λ _1H , λ _2H , λ _3H ) and the corresponding half lengths of their own sound waves

and

an oscillating mass-elastic body of air volume enclosed in an internal three-dimensional air cavity 13 of a technical room 1, with discrete values of operating dominant functional frequencies of sound oscillations f _ms , represented at least (first of all) by the three lowest harmonic components of the sound emission spectrum of the ShSTO 14, characterized by multiple sound wavelengths λ _ms -λ _1s , λ _2s and λ _3s . Thus, in view of the implemented condition of preventing (effective attenuation) of the development of the physical process of resonant amplification of sound radiation, the corresponding effects of reducing the levels of sound radiation (noise) are realized both inside the technical room 1 and outside it - in adjacent rooms that make up the building, or in an open surrounding area adjacent to a building, in the form of airborne and structural noise transmitted through an insufficiently high (unsatisfactory a) the sound insulating capacity of the wall pre-walls (pos. 7 and 5), the elements of the door opening and the entrance door (pos. 9 and 10), and the ventilation openings (pos. 12), as illustrated in particular in the diagrams of FIG. 10 and 11. There is also the prevention (exclusion) of the occurrence of beatings of interacting acoustic signals (sound waves) with close values of the frequencies of sound vibrations f _ms and f _mA .

Sound radiation of a typical ShGTO 14, represented, in particular, by various types of piston machines - piston internal combustion engines, compressors, pumps, as well as various types of electric generators, power electrical transformers, mechanical gearboxes, is accompanied by concomitant release into the environment (into the internal three-dimensional air cavity 13 of the technical room 1) excess parasitic heat energy. As a result, a corresponding temperature field is formed in said internal three-dimensional air cavity 13, affecting the propagation conditions of sound energy in said internal three-dimensional air cavity 13 of the technical room 1. There is also a concomitant physical influence of functioning ventilation systems (climate control), as well as temperature events that take place. impacts of the external environment.

рабочей доминирующей функциональной частоты f_ms (ее трех кратных доминирующих частотных гармоник - f_1s, f_2s, f_3s) в составе спектра звукового излучения ШГТО 14, следует учитывать текущие физические параметры массо-упругого тела воздушного объема внутреннего пространства внутренней трехмерной воздушной полости 13 технического помещения 1, которые влияют на изменение значения длин звуковых волн λ_ms, распространяемых в воздушной среде технического помещения 1. Как известно (см. информационные источники [4]…[13]), длина звуковой волны λ определяется исходя из скорости распространения звука с и частоты звуковых колебаний f:To determine the half-wavelengths of the sound waves

The operating dominant functional frequency f _ms (its three multiple dominant frequency harmonics - f _1s , f _2s , f _3s ) in the composition of the sound emission spectrum of the State Technical Service 14 should take into account the current physical parameters of the mass-elastic body of the air volume rooms 1, which affect the change in the sound wavelengths λ _ms , distributed in the air environment of the technical room 1. As is known (see information sources [4] ... [13]), the sound wavelength λ determines based on the speed of sound propagation c and the frequency of sound vibrations f:

where λ is the length of the sound wave, m;

f is the frequency of sound vibrations, Hz (c ^-1 );

с - speed of sound waves propagation (sound speed), m / s;

, Springer-Verlag Berlin Heidelberg, 2007;[4] - Helmut V. Fuchs. Schallabsorber und

, Springer-Verlag Berlin Heidelberg, 2007;

[5] - N.I. Ivanov. Engineering acoustics. The theory and practice of dealing with noise. - M .: Logos, 2010. - 424 p .;

[6] - V.B. Stupid Reducing noise from power equipment. - M .: Publishing house MEI, 2005. - 232 p .;

[7] - D.F. Lazaroiu, N.L. Bikir The noise of electrical machines and transformers. Translated from room., - M .: "Energy", 1973. - 271 p .;

[8] - Fighting industrial noise. Directory. Ed. E.Y. Yudina, Mashinostroenie, M., 1985, 400 pp .;

[9] - Handbook for the control of industrial noise. Translation from English L.B. Scriabina and N.I. Shabanova, M., Mechanical Engineering, 1979, 447 pp .;

[10] - Technical Acoustics Reference. Ed. M. Hekla and Kh.A. Muller L., Shipbuilding, 1980, 440 pp .;

[11] - G.L. Osipov, E.Ya. Yudin, G. Hübner and others. Reducing noise in buildings and residential areas. - M .: stroiizdat, 1987. - 558 s .;

[12] - О.Д. Shebalin. Physical fundamentals of mechanics and acoustics: Proc. allowance. - M .: Higher. school, 1981. - 261 pp .;

[13] - Traffic noise. / Translation from English. K.G. Bomstein Ed. E.Y. Tolsky, G.V. Butakova, B.N. Melnikov. - M: Transport, 1995. - 368 p.

Also in the cited references of the technical description of the application for the invention on the specified information sources [4] ... [13], the dependences of the speed of sound propagation in the air environment on the change of some of its physical parameters are given. Thus, according to the Laplace formula, the speed of sound in air is determined according to the following expression:

Where

x is the ratio of the specific heats of gas at constant pressure and volume (for air, which is mainly diatomic gas, x = 1.40);

p - static atmospheric (barometric) pressure, N / m ² ;

ρ is the air density, kg / m ³ .

According to the information source [12], p. 224, the value of p / ρ is constant. With an increase in the atmospheric pressure p, the density of the air ρ increases, and as the pressure decreases, the density ρ decreases. Also, as follows from page 14 of the text of the information source [13], the speed of sound c does not depend on the change in atmospheric pressure p. A human ear balances a constant or slowly varying atmospheric pressure p and its response to pressure fluctuations begins with frequencies f of these oscillations equal to 16 ... 22 Hz. Therefore, the effect on the speed of sound from a change in atmospheric pressure p in the air volume of the internal three-dimensional air cavity 13 of the technical room 1 can be neglected.

According to page 25 of the information source [12], the influence of air humidity on the speed of sound c in the region of audible sounds is negligible. Thus, in particular, the values of the speed of sound with its distribution in dry air and in air with a relative humidity of 100% differ only by about 1.5%. Consequently, when determining the influence of air humidity on the change in the sound wavelength λ _{ms of the} working dominant functional frequency f _ms (three multiple dominant frequency harmonics - f _1s , f _2s , f _3s ) of the sound radiation produced by STG 14 in technical room 1, you can also neglect .

At the same time, it is known that the speed of sound in air essentially depends on its temperature (t ° C). This dependence is easy to establish using the Mendeleev-Klaperon formula:

where V _μ is the molar volume, m ³ ;

R _g is the molar gas constant;

T _to - thermodynamic temperature, K.

Substituting the value of p in the Laplace formula (3), we get:

Substituting the values of x, R _r , V _μ and ρ known for air into expression (5), and also converting the temperature values on the Kelvin scale (K) to values on the Celsius scale (t ° C), we obtain the known functional dependence of the speed of sound with in the air from the temperature of the air:

where c (t) is the speed of propagation of sound waves in an elastic air medium at air temperature t ° C, m / s;

t ° C - air temperature in ° C.

, определяющаяся на ее низших собственных акустических модах, представленных собственными акустическими колебаниями массо-упругого тела воздушного объема, заключенного во внутреннем пространстве внутренней трехмерной воздушной полости 13 технического помещения 1, в направлении одного из габаритных размеров А внутренней трехмерной воздушной полости 13 технического помещения 1 (длины L, ширины В или высоты Н), должна быть соответствующим образом «температурно» скорректирована и может быть определена согласно выражения (7):Thus, taking into account the insignificant effect of changes in atmospheric pressure and air humidity, and a significant effect of air temperature on the speed of sound waves c (t), taking into account expressions (2) and (6), the half-length of the sound wave

determined on its lower proper acoustic modes, represented by its own acoustic oscillations of a mass-elastic body of air volume enclosed in the internal space of the internal three-dimensional air cavity 13 of the technical room 1, in the direction of one of the dimensions A of the internal three-dimensional air cavity 13 of the technical room 1 L, width B or height H), should be appropriately “temperature-adjusted” and can be determined according to expression (7):

Sound wavelengths λ _ms (λ _1s , λ _2s and λ _3s ) emitted by the ShGTO 14 at discrete values of the operating dominant functional frequencies f _ms (three multiple dominant frequency harmonics f _1s , f _2s , f _3s ) should also be determined taking into account the temperature range of the air enclosed in the internal three-dimensional air cavity 13 of the technical room 1 (in the steady-state stabilized operating temperature range of the technical room 1 under consideration, with the ShGTO 14 mounted in it).

Declared as an invention, the technical solution for the design of a low-noise technical room 1 is aimed at eliminating (preventing) the implementation of the development of physical processes of resonant amplification of sound radiation and the occurrence of beats of interacting acoustic signals (sound waves) with close values of sound vibrational frequencies f _ms and f _mA , produced by ShGTO 14 located in it (several ShGTO 14) and possible dynamic excitation of resonant acoustic numbers carried out by it Bayan of a mass-elastic body of air volume enclosed in the internal space of an internal three-dimensional air cavity 13 of a technical room 1. In this type of declared low-noise design of a technical room 1, development of the physical process of dynamic excitation of resonant acoustic oscillations of a mass-elastic body of a three-dimensional internal air mass is prevented (effectively weakened). cavity 13 technical room 1, bounded by its side walls 7, front wall 8, rear wall 11, ceiling 5, floor 6, d the right opening 9 with the entrance door 10 closed. In the end, it helps to ensure the acoustic safety of the environment (noise reduction both directly inside the technical room 1 and outside it). First of all, this applies to technical rooms 1, in which ShGTO 14 intensively radiating sound energy is placed (several ShGTO 14), whose sound emission spectrum is characterized (identified) by one constant (constant) discrete sound frequency value f _1s (or several discrete values frequencies of sound waves f _ms , with m> 1: f _2s , f _3s , f _4s , ...), the sound pressure level of which is dominantly allocated over the other frequency components of the sound spectrum (see Fig. 1 ... 4). In these cases, in a determining measure, the negative “acoustic quality” of the technical room 1 is formed and the task of its substantial improvement arises.

Impact on the physical process of reducing the radiation of sound energy, located in the technical room 1 ShGTO 14, is carried out by eliminating (effective attenuation) of the negative response of the mass-elastic air body to the air volume of the internal three-dimensional air cavity 13 in the form of the missing resonant vibro-acoustic response to the its sound radiation SHGTO 14, due to the elimination of the resonant coincidence of unacceptably close values of their frequency-modal characteristics. In this case, the exclusion (weakening) of the negative dynamic reaction from the impact of the dynamic excitation process on the lower intrinsic acoustic modes of the mass-elastic body of the air volume enclosed within the internal three-dimensional air cavity 13 of the specified technical room 1, included in the acoustic field formed in it is meant. As is known [4, 8, 10], excited half-wave acoustic resonances (and multiple frequency harmonics) of closed air volumes formed in the internal three-dimensional air cavities of 13 technical rooms 1, are characterized by pronounced natural (resonant) frequencies of acoustic oscillations, with integers ( m) half-lengths of sound waves (λ / 2) that fit between opposite (opposite) rigid wall sound-reflecting surfaces (including between the floor and ceiling surfaces) of the technical room 1. In view of that the typical dimensions of the technical premises 1 (respectively, and the dimensions of the formed internal three-dimensional air cavities 13), as a rule, are measured by several meters (several tens of meters), commensurate with lengths λ (half lengths λ / 2) of the emitted low-frequency (f≤ 300 Hz) of sound waves, then the potentially possible resonant amplification of sound radiation on the emerging lower proper acoustic modes is also predetermined by the indicated low-frequency sound range. At the same time, as is known from [4, 5, 8, 9, 10], the absorption efficiency of low-frequency acoustic radiation of acoustic energy (20 ... 300 Hz) used by typical porous sound-absorbing elements (sound-absorbing panels, linings, linings, upholstery) used in the noise control technique, in contrast to the medium and high-frequency sound radiation, it is quite low (ineffective). This, in turn, makes it necessary to use rather massive (large-sized thick-walled) expensive sound-absorbing elements, including mounting them with an additional (intermediate) air gap on the relatively rigid sound-reflecting wall surface, which ultimately reduces the useful working space of the technical room 1. For this reason, a more productive technical technique is to reduce the intensity of resonant radiation and attenuate the transmission of acoustic energy by low frequency waves, is the implementation of the physical process of eliminating the intrinsic resonant dynamic excitation of a low-frequency acoustic system, carried out directly at the low-frequency sources themselves (generation source - STEP 14), represented by the excitation source of the internal three-dimensional air cavity 13, represented, in this case, by the mass-elastic body of the air volume, concentrated in the internal three-dimensional air cavity 13 technical room 1, characterized by its own bubbled frequencies f _mA sound vibrations and acoustic modes with their own acoustic wavelength λ _mA. The proposed (claimed) technical solution was aimed at solving the specified technical problem.

On the relevance and ways to solve the problems of reducing low-frequency sound radiation at the dominant values of individual discrete frequency components f _ms , emitted in the broadband spectra of sound pressure of various types ShGTO 14, operated (mounted) in the technical rooms 1, in particular, piston internal combustion engines, mechanical gearboxes , rotors, fan installations, electric generators, electrical transformers, traction machines, smoke exhausters (axial, centrifugal type), pumps and compressors (piston, prices tbebezhnyh) - indicated in the well-known information sources [4 ... 10], and also confirmed by the results of experimental studies of the authors, shown in FIG. 1 ... 4.

Taking into account the functioning constant (steady-state) speed and load modes of operation of the above-used SHGTO 14, the dominant discrete low-frequency components f _ms emitted in the broadband spectral sound pressure are also constant (with constant sound frequency f _ms ), as follows from the FIG. 1, 2, 3, 4. This applies, in particular, to ShGTO 14, represented by a power electric transformer, with prominent frequency harmonics f _1s , f _2s , f _3s equal to 100, 200 and 300 Hz, multiples of the constant value of the industrial frequency current f _c = 50 Hz (see Fig. 1 and 2). Similarly, this may refer to constant steady-state values of nominal rotational frequencies n _s (f _ms ) of the shafts of piston machines (internal combustion engines, compressors, pumps), electric generators, mechanical or electric fans, mechanical gearboxes, as well as periodic unbalanced unbalanced masses unbalanced forces and moments of crank mechanisms of piston machines. Sources (dynamic pathogens) of intense sound radiation on these prominent dominant discrete components f _ms , with the formation of the corresponding acoustic fields, are, in particular, gas (air) pulsations in the processes of air suction into the cylinders of piston machines, periodic dynamic movements of air by blades (blades) fan impellers, dynamic imbalances of rotating shafts, unbalanced forces and unbalanced moments of reciprocating moving masses of a piston x machines (connecting rod-piston masses of the crank mechanism, the crank shaft), alternating dynamic loads working processes intermating teeth in the toothing of gear units, dynamic alternating electromagnetic and magnetostrictive forces of electrical machines and installations. The numerical values of the frequencies of sound vibrations of the considered dominant discrete components f _{ms are} determined experimentally using appropriate recording and analyzing vibroacoustic equipment (as shown in Figures 1, 2, 3, 4 as illustrative examples), or determined by calculation — taking into account the well-known predetermined constant steady speed (load) of the operating mode n _s of the unit or system, and the design characteristics of components of a particular TRP 14 (crankshaft rotational speeds, cylinder numbers and piston machine workflow tactics, number of blades (blades) of the fan impeller, number of teeth of mating toothed gear teeth, ac frequency), as follows from well-known information sources [4 ... 10].

On page 5-14 of the information source [4], the results of studies of the natural acoustic oscillations (natural acoustic modes) of a mass-elastic body of air volume, represented by the internal cavity of a rectangular room bounded by rigid sound-reflecting walls (a hollow cylinder with a rectangle base), are presented. According to him, the technical room 1 was investigated with the overall dimensions of the internal three-dimensional air cavity 13 L⋅B⋅H = 3⋅4⋅5 m (see Fig. 2.1 in [4], presented in Fig. 5 of the application for invention). Sound vibrations of the mass-elastic body of the air volume of the internal three-dimensional air cavity 13 were excited by a speaker 2 located in one of the angular spatial zones of the technical room 1. Measurements of sound pressure levels were recorded by a measuring microphone 3 located in the opposite corner of the technical room 1. In FIG. 6 of the application for the invention shows the results of measurements of the physical parameters of the excited resultant sound field of the technical room 1, presented in the form of registered resonant responses at the natural frequencies of sound oscillations f _mA (f _mL , f _mB , f _mH ), which are realized on the acoustic modes of the air cavity studied 13 technical room 1. In FIG. 7 (see also Fig. 2.2 in [4]) visualized the three-dimensional distribution of sound pressures in the first lower longitudinal and transverse acoustic modes (f _1L , f _1B ) of the studied cylindrical internal three-dimensional three-dimensional air cavity 13. In [4], a good the correlation of the obtained results of experimental measurements with the calculated results of determining the natural frequencies of sound oscillations f _mA (f _mL , f _mB , f _mH ) of the own acoustic modes of an elastically oscillating body of air volume enclosed in an internal the space of the internal three-dimensional air cavity 13 with overall dimensions of length L, width В and height Н, technical room 1, limited by rigid sound-reflecting side walls 7, front wall 8, rear wall 11, floor 6, ceiling 5, closed by an entrance door 10. In general form , their discrete values are determined according to expression (1) above.

FIG. 8 is a schematic diagram of the experimental studies of the natural sound vibrations (frequencies, acoustic modes) of the mass-elastic air volume of the internal three-dimensional air cavity 13 of the technical room 1, with their overall dimensions L⋅B⋅H = 10⋅10 different from the technical room 1 considered above. ⋅4 m. Experimental studies were carried out in the technical room 1, represented by the room of the test acoustic laboratory, using the hardware-software complex acus nical holography (Spatial Transformation of Sound Fields) type STSF 7688 (cp. "Brüel &Kjær", Denmark). FIG. 9 shows the results of experimental studies of the natural frequencies of acoustic oscillations of natural acoustic modes, represented by discrete values of natural acoustic frequencies of a mass-elastic body of air volume f _mA , enclosed in an internal three-dimensional air cavity 13 of the technical room under study 1 (acoustic test room) directions of overall dimensions A (L, B, H) of a technical room 1.

Analysis of the research results shown in FIG. 6, 7, 9 indicates low-frequency resonant amplifications of excited natural acoustic oscillations of a mass-elastic body of an air volume inside three-dimensional air cavity 13, represented in the form of a rectangular parallelepiped, technical room 1, limited by rigid sound-reflecting side walls 7, front wall 8, back wall 11 , floor 6, ceiling 5, closed entrance door 10. They are most intense at their own frequencies of sound vibrations f _mA (f _mL , f _mB , f _mH ) with the corresponding formation of their own These are the acoustic modes of the internal three-dimensional air cavity 13 (Fig. 7) and are characterized by low Q-factors of the internal acoustic resonance of the internal three-dimensional air cavity 13 of the technical room 1 Q _a with narrow frequency response of the dynamic excitation (see Fig. 6 and 9). This indicates, in particular, the fundamental possibility of realizing the effective frequency detuning (frequency mismatch) of the source of dynamic excitation (sound radiation of the ShGTO 14) from the natural acoustic oscillations of the mass-elastic body of air volume contained in the internal three-dimensional air cavity 13 (natural frequencies f _mL , f _mB , f _mH sound vibrations, with emerging intrinsic acoustic modes). It can be due to some predetermined frequency offset (mismatch) of the values of the natural frequencies of sound oscillations f _mA (f _mL , f _mB , f _mH ), which are formed on the own acoustic modes of the internal three-dimensional air cavity 13, from the values of the working dominant functional frequencies f _ms sound radiation SHGTO 14. Similarly, can be realized a predetermined offset values dominant functional working frequency f _ms sound radiation SHGTO 14 (if permitted by the specifications of his e spluatatsii). The set value of the frequency offset (mismatch) of the frequencies of the sound oscillations f _mA (f _mL , f _mB , f _mH ) of the natural acoustic modes of the internal three-dimensional air cavity 13 from the values of the operating dominant functional frequencies f _{ms of the} sound radiation of the ShGTO 14 should be sufficient to prevent the occurrence of physical the process of occurrence of the beating of interacting acoustic signals (sound waves) with close values of the frequencies of sound vibrations f _ms and f _mA .

FIG. 1-4 shows the experimental results of measurements of the spectra of sound pressure (FFT spectra) emitted by various types of ShGTO 14 (power transformer, industrial fan, piston compressor) placed in the corresponding technical rooms 1. The results of experimental studies shown in FIG. 1-4 indicate the presence of identified working dominant functional frequencies f _{ms of the} sound radiation of the studied ShGTO 14 forming the sound field of the technical room 1. In particular, the results of measuring the narrow-band sound spectrum emitted by the ETPR located in the basement floor of the building of the test center of an industrial enterprise ( see Fig. 1), indicate the dominant functional frequencies f _ms in the sound spectrum, represented by three low-frequency harmonic components Avglyuschim spectrum of sound radiation (f _1s , f _2s , f _3s ) ShGTO 14, presented in the form of a power electric transformer, which are the values of f _1s = 100 Hz, f _2s = 200 Hz, f _3s = 300 Hz, multiples of the frequency of the alternating current f _c = 50 Hz. It should be noted here that ultrasonic sounding at registered discrete frequencies (f _1s , f _2s , f _3s ) exceed by more than 20 dB (10 times in linear units of measurement) the ultrasonic sound frequency of other frequency components of the ETPRT sound radiation and, thus, practically completely dominate in the sound field of the spatial zone of the closed doorway 9 of the technical room 1, presented in the form of an ETPRT and in the territory adjacent to it. It is for this reason that the indicated acoustic radiation is characterized by a “low-frequency electrical transformer hum” according to subjective auditory perception.

When measuring 1/3 of an octave sound spectrum emitted by a 3MK 260-1 power transformer of the company PLATTHAUS (Germany), located in the technical room 1 of the test center of an industrial enterprise (see Fig. 2), the working dominant functional frequencies f _{ms of the} sound radiation are also recorded ShGTO 14 in the form of a pronounced low-frequency "electric transformer hum" of a power electric transformer: f _1s = 100 Hz, f _2s = 200 Hz, f _3s = 300 Hz (it is part of the width of the frequency band with the center 315 Hz). Ultrasonic sounding at registered discrete frequencies (f _1s , f _2s , f _3s ) exceeds by more than 15 dB (5.6 times in linear units of measurement). Ultrasonic sounding of other frequency components of the presented spectrum of sound radiation of the studied electric transformer, which also testifies to their dominant contribution to the formation of the ambient sound field of a technical room 1.

The 1/3 octave sound spectrum emitted by the AXIPAL FTDA-050-3 industrial fan (Russia) mounted in the technical room 1, represented by the acoustic test laboratory room (see Fig. 3), identifies the two low-frequency spectral components the dominant functional frequencies of sound radiation of the ShGTO 14 are in the form of a blade (blade) impeller rotation frequency f _1s = 50 Hz and a multiple harmonic f _2s = 100 Hz. Ultrasonic sounding at marked discrete frequencies (f _1s , f _2s ) by more than 25 dB (17.8 times in linear units of measure) exceed the ultrasonic sounding of the medium and high frequency range of the studied spectrum of the sound radiation of the SHTO 14 under study. This allows to qualify the indicated frequencies f _1s and f _2s as the dominant low-frequency sound emitters that form the sound field of the technical room 1.

The measurement results of a 1/3 octave sound spectrum emitted by a piston compressor produced by STAL (Sweden), mounted in the technical room 1 of the refrigeration compressor station of the testing center of an industrial enterprise, are shown in FIG. 4, two pronounced discrete working dominant functional frequencies of the SGTO sound radiation are also identified - f _1s = 200 Hz and f _2s = 400 Hz. Ultrasonic sounding at registered discrete values of sound frequencies (f _1s , f _2s ) by more than 10 dB (3.16 times in linear units of measure) exceed the ultrasonic sound frequency of the other frequency components of the spectrum of sound radiation recorded in the technical room of a refrigeration unit.

), укладывающимися между противолежащими жесткими звукоотражающими поверхностями стеновых (пола и потолка) ограждений технического помещения 1.Thus, as follows from the results of the studies shown in FIG. 1-4, the working dominant functional frequencies of sound radiation f _{ms of the} studied ShGTO 14, mounted in the corresponding technical rooms 1, of various dimensions L, B, H, are concentrated in the actual low-frequency region of the sound spectrum (50 ... 400 Hz), sound wavelength _ms are located in the meter range of sound frequencies that contributes to their resonant frequency-wave coincidence with dimensions of mass-elastic three-dimensional air volume inside the air chamber 13 technical room 1, hara terizuemogo own respective acoustic modes of acoustic waves with wavelengths λ _mA (half-lengths

), stacked between the opposite rigid sound reflecting surfaces of the wall (floor and ceiling) fences of the technical room 1.

The low-noise technical room 1 claimed as an invention contains a ShGTT 14 installed in its internal space (internal three-dimensional air cavity 13) 14 (several ShGTO 14), the dominant sound radiation of which is predetermined by steady-state constant (constant) values of low-frequency discrete spectral components the sound field of the technical room 1 relative to the remaining frequency components of the sound spectrum. As a typical ShGTO 14 are considered, in particular, a power electrical transformer, a piston engine and / or a piston compressor as part of a diesel generator, a compressor station, an autonomous pumping unit installed in the technical room 1, or a fan-climate unit. This type of ShGTO 14, according to their passport technical characteristics, qualify as a permanent (steady) speed (operational) mode of operation. Accordingly, during their operation, a steady-state sound field is generated, containing in its spectral composition pronounced discrete values of the frequency components of the spectrum of sound radiation associated with the working processes implemented during the operation of the ShGTO 14. On the other hand, in this type of technical rooms 1 is formed (including using additional technical means) stabilized operating operating temperature of the air environment, with the formation of a constant steady-state temperature Field of the air volume inside the air chamber 13 of the three-dimensional technical room 1 in which the sound waves propagate generated SHGTO 14.

The physical processes of generation and the propagation of sound radiation from the ShGTO 14 are schematically indicated in FIG. ten.

и

внутренней трехмерной воздушной полости 13 технического помещения 1 с половинами длин звуковых волн рабочих доминирующих функциональных дискретных частотных гармоник спектра звукового излучения

, производимого ШГТО 14 (см. фиг. 12.2, 12.3, 13.2, 13.3, 14.2, 14.3). В результате такого типа компоновочно-конструктивных исполнений, возможна реализация исключения (эффективного ослабления) развития физического процесса частотно-волнового совпадения и последующего динамического резонансного усиления уровней взаимодействующих звуковых давлений и возникновения биений взаимодействующих акустических сигналов (звуковых волн) с близкими значениями частот на указанных рабочих доминирующих функциональных гармониках f_ms (f_1s, f_2s, f_3s) спектра звукового излучения ШГТО 14 и низших собственных (резонансных) акустических мод f_mA (f_mL, f_mB, f_mH) внутренней трехмерной воздушной полости 13 технического помещения 1, в отличие от вариантного исполнения, как это представлено на фиг. 12.1, 13.1 и 14.1, когда имеет место физический процесс их полного частотно-волнового совпадения.FIG. 11 shows sound pressure diagrams (pos. 15), distributed at natural frequencies of sound vibrations of three lower natural (resonant) acoustic modes f _mL (f _1L , f _2L , f _3L ), f _mB (f _1B , f _2B , f _3B ) and f _mH (f _1H , f _2H , f _3H ). Non-uniform, with pronounced maxima and minima, spatial distributions of amplitude values (sound pressure levels) P _mA -P _mL (P _1L , P _2L , P _3L ), P _mB (P _1B , P _2B , P _3B ) and P _mH (P _1H , P _2H , P _3H ), indicate the potential implementation of individual variant designs, as presented in the claimed technical device, when the selected dimensions A (L, B, H) of the internal three-dimensional air cavity 13 of the technical room 1 exclude multiple coincidences of the halves sound wavelengths of lower intrinsic acoustic sky mods

and

internal three-dimensional air cavity 13 technical room 1 with one-half the sound wavelengths of the workers dominant functional discrete frequency harmonics of the spectrum of sound radiation

, produced by ShGTO 14 (see Fig. 12.2, 12.3, 13.2, 13.3, 14.2, 14.3). As a result of this type of design and construction, it is possible to exclude (effectively weaken) the development of the physical process of frequency-wave coincidence and subsequent dynamic resonant amplification of interacting sound pressure levels and the occurrence of beats of interacting acoustic signals (sound waves) with similar frequencies functional harmonics f _ms (f _1s , f _2s , f _3s ) of the sound emission spectrum of the ShGTO 14 and lower intrinsic (resonant) ak the fomic _mA f (f _mL , f _mB , f _mH ) internal three-dimensional air cavity 13 of the technical room 1, in contrast to the variant version, as shown in FIG. 12.1, 13.1 and 14.1, when the physical process of their complete frequency-wave coincidence takes place.

указанных рабочих доминирующих функциональных частот f_ms, представленных тремя выделяющимися доминирующими гармоническими составляющими спектра звукового излучения f_1s, f_2s, f_3s.Thus, figures 12, 13, 14 schematically illustrate the processes of implementing the development of the physical process as a potentially possible negative resonant amplification of sound radiation and the emergence of a physical process of the beating of interacting acoustic signals (sound waves) with similar values of sound vibration frequencies f _ms and f _mA (FIG. 12.1, 13.1, 14.1), and the exclusion (effective attenuation) of the resonant amplification of sound radiation and the occurrence of the physical process of the beating of interacting acoustic signals (sound O waves) with close values f _ms and f _mA acoustic oscillation frequencies (Fig. 12.2, 12.3, 13.2, 13.3, 14.2, 14.3) arising in the inner three-dimensional air cavity 13 technical room 1 on discrete values of the natural frequencies of sound vibrations f _{mA (f mL, f mB, f} mH), formed on the natural acoustic modes of the three-dimensional inner air cavity 13 technical room 1. The results in these figures parameters f _mL - defined in the direction of the overall length L three-dimensional internal space inside the air cavity 13 technical of room 1, f _mB - in the direction of the overall width in the inner space inside the three-dimensional air cavity 13 technical room 1, f _mH - in the direction of the overall height H of the inner space inside the three-dimensional air cavity 13 technical room 1, with the corresponding frequency wave ( multiple) full matches (FIG. 12.1, 13.1, 14.1) or inconsistencies (Fig. 12.2, 12.3, 13.2, 13.3, 14.2, 14.3) with the emitted sound wavelengths λ _ms (multiples of half-lengths of sound waves

these working dominant functional frequencies f _ms , represented by three prominent dominant harmonic components of the spectrum of sound radiation f _1s , f _2s , f _3s .

на низших (m=1, 2, 3) собственных акустических модах, представленных собственными акустическими колебаниями массо-упругого тела воздушного объема, заключенного во внутренней трехмерной воздушной полости 13 (ограниченного соответствующими габаритами L, В, Н) технического помещения 1

, с половинами длин звуковых волн дискретных значений рабочих доминирующих функциональных частот f_ms, в виде трех кратных низших гармонических составляющих спектра доминирующих дискретных частот f_1s, f_2s, f_3s (

и

), излучаемого ШГТО 14. В это же время, представленные вариантные конструктивные исполнения соответствующих габаритных размеров внутреннего пространства внутренней трехмерной воздушной полости 13 технического помещения 1, представленные на фиг. 12.2, 12.3, 13.2, 13.3, 14.2, 14.3, частотно-волновое резонансное совпадение исключают (эффективно ослабляют), что является позитивным фактом рассогласования резонансных звукоусиливающих совпадений. Представленный в описании заявки и формуле изобретения предложенный выбор заданных соотношений габаритных размеров внутренней трехмерной воздушной полости 13 A (L, В, Н) с акустическими характеристиками звукового излучения ШГТО 14 на установившемся скоростном эксплуатационном режиме работы (λ_ms, n_s), в связи с этим может быть использован на стадии проектирования или модернизации для исполнения низкошумных технических помещений без дополнительного применения в их конструкциях дорогостоящих шумопонижающих материалов и технических устройств.Schematic variant designs of the overall dimensions of the internal space of the air space 13 A (L, B, H) of the technical room 1, shown in FIG. 12.1, 13.1, 14.1 illustrate examples of negative resonant coincidence of half sound wavelengths.

on lower (m = 1, 2, 3) natural acoustic modes, represented by natural acoustic oscillations of the mass-elastic body of the air volume contained in the internal three-dimensional air cavity 13 (limited by the corresponding dimensions L, H, H) of the technical room 1

, with the halves of the sound wave lengths of discrete values of the working dominant functional frequencies f _ms , in the form of three multiple lower harmonic components of the spectrum of the dominant discrete frequencies f _1s , f _2s , f _3s (

and

) emitted by the ShGTO 14. At the same time, the presented variant designs of the corresponding overall dimensions of the internal space of the internal three-dimensional air cavity 13 of the technical room 1, shown in FIG. 12.2, 12.3, 13.2, 13.3, 14.2, 14.3, the frequency-wave resonance coincidence is excluded (effectively attenuated), which is a positive fact of the mismatch of resonant sound-amplifying coincidences. Introduced in the description of the application and claims, the proposed selection of predetermined ratios of dimensions inside the three-dimensional air cavity 13 A (L, B, H) with the acoustic characteristics of the acoustic radiation SHGTO 14 at steady speed operational mode (λ _ms, n _s), in connection with This can be used at the design or modernization stage for the execution of low-noise technical premises without the additional use of expensive noise-reducing materials and technical devices in their structures. STV.

, излучаемых активной частью силового электротрансформатора на его дискретных значениях рабочих доминирующих функциональных частотах f_ms, представленных тремя гармоническими составляющими спектра звукового излучения f_1s=100 Гц, f_2s=200 Гц и f_3s=300 Гц, кратных промышленной частоте сети переменного тока f_c=50 Гц, к которой подключен силовой электротрансформатор. Для предотвращения (эффективного подавления) развития физического процесса резонансного усиления звуковых колебаний массо-упругим телом воздушного объема, заключенного во внутреннем пространстве внутренней трехмерной воздушной полости 13 технического помещения 1 ЭТПЗТ, согласно заявляемого технического решения предлагается на стадии ее проектирования (или модернизации) предусмотреть реализацию технических решений для введения заданного рассогласования частотно-модальных параметров массо-упругого тела воздушного объема, заключенного во внутреннем пространстве внутренней трехмерной воздушной полости 13, характеризуемых собственными акустическими модами, формирующимися в трехмерных направлениях габаритных параметров внутренней трехмерной воздушной полости 13 A (L, В, Н) на дискретных значениях собственных частот звуковых колебаний f_mA-f_mL, f_mB, f_mH., с частотно-модальными параметрами рабочих доминирующих функциональных частот f_ms трех выделяющихся (наиболее интенсивных) гармонических составляющих УЗД звукового спектра, излучаемого силовым электротрансформатором - f_1s=100 Гц, f_2s=200 Гц и f_3s=300 Гц. Выбранные при разработке (модернизации) конструкций технического помещения 1 габаритные размеры А внутренней трехмерной воздушной полости 13 технического помещения 1 (L, В, Н) в этих случаях не должны быть равны или кратны половинам длин звуковых волн λ_ms (

и

) рабочих функциональных частот трех гармонических составляющих спектра звукового излучения ШГТО 14 (f_1s=100 Гц, f_2s=200 Гц и f_3s=300 Гц - для рассмотренного иллюстративного примера ШГТО 14, представленного в виде силового электротрансформатора, смонтированного в техническом помещении 1 ЭТПЗТ), отличаясь от их значений, по крайней мере, не менее чем в 1,06 раза, как это представлено в выражениях (8)…(13):A concretized illustrative example of a variant execution of a low-noise technical room 1 with a ShGTO 14 located in it, which is characterized by sound radiation dominating in the spectrum at individual low-frequency discrete components, can be represented by ETPRT (see Fig. 15). As it is known, the noise radiation of a power electric transformer represented by ShGTO 14 is characterized by discrete components of the intensity of radiation of acoustic energy transmitted to the environment (in adjacent residential areas, to adjacent premises of a building construction) dominant at the individual frequencies, as illustrated examples of FIG. 1 and FIG. 2. Of most interest is the dominant nature of low-frequency noise radiation from power electrical transformers (f _ms = 100 ... 300 Hz), which has, as is known, high penetrating power, with intensive propagation over long distances without a noticeable fraction of the dissipative absorption of acoustic energy. The sound insulation capacity of typical enclosing structures of ETPZT in most cases is insufficient (ineffective). In addition to this, the design of a technical device, including a technical room 1 of an ETPZT, may contain a number of composite structural elements (pos. 5, 7, 8, 9, 10, 11, 12), characterized not only by weak sound-insulating properties, but also contributing to enhanced transmission acoustic energy from the closed space of the internal three-dimensional air cavity 13 of the technical room 1, both into the open space and into the adjacent rooms of the building construction. This means light, thin-walled entrance doors (pos. 10) and doorways (pos. 9), various types of translucent functional communication and technological openings (slots) contained in doorway 9 and entrance door 10, as well as open ventilation openings (pos. 12). These technical problems are of particular relevance in the development of powerful low-frequency vibroacoustic processes formed in closed internal three-dimensional air cavities 13, limited by rigid sound-reflecting wall structures of technical premises of ETPZT, contributing to the formation of powerful internal cavitary air half-wave acoustic resonances, in the form of dynamically excited mass response oscillations elastic bodies of air volumes enclosed in the inner space All of these internal three-dimensional air cavities 13. In these cases, the use of thin-walled, with low specific surface weight structural elements of the enclosures of technical rooms 1 ETPZT contributes to their transformation into intensive secondary structural emitters of panel-type sound energy, amplifying the noise radiation as inside the internal three-dimensional air cavity 13 technical rooms 1 ETPZT (see Fig. 2), and outside of it - in the open space or adjacent areas of the building building (see FIG. one). In particular, the specified resonant amplification of sound radiation of an ETPZT manifests itself when the overall dimensions A of an internal three-dimensional air cavity 13 of a technical room 1 of an ETPZT along an overall length L, an overall width B, an overall height H are equal to and / or multiples of half-lengths of sound waves

emitted by the active part of the power electrical transformer at its discrete values of the operating dominant functional frequencies f _ms , represented by the three harmonic components of the spectrum of sound radiation f _1s = 100 Hz, f _2s = 200 Hz and f _3s = 300 Hz, multiples of the industrial frequency of the alternating current network f _c = 50 Hz, to which the power electrical transformer is connected. To prevent (effective suppression) of the development of the physical process of resonant amplification of sound vibrations by the mass-elastic body of air volume enclosed in the internal space of the internal three-dimensional air cavity 13 of the technical room 1 of ETPRT, according to the proposed technical solution, it is proposed at the design stage (or modernization) to implement technical solutions for the introduction of a given mismatch frequency-modal parameters of the mass-elastic body of air volume, concluded in the internal space of the internal three-dimensional air cavity 13, characterized by their own acoustic modes, which form in the three-dimensional directions the overall parameters of the internal three-dimensional air cavity 13 A (L, B, H) at discrete values of the natural frequencies of sound vibrations f _{mA -} f _mL , f _mB , f _mH ., with frequency-modal parameters of the working dominant functional frequencies f _{ms of the} three distinguished (most intense) harmonic components of the ultrasound of the sound spectrum emitted by a power electrotransformer - f _1s = 100 Hz, f _2s = 200 Hz and f _3s = 300 Hz. The dimensions A of the internal three-dimensional air cavity 13 of the technical room 1 (L, B, H) selected in the development (modernization) of the technical room 1 in these cases should not be equal to or multiple to half of the sound wavelengths λ _ms (

and

) working functional frequencies of the three harmonic components of the sound emission spectrum of ShGTO 14 (f _1s = 100 Hz, f _2s = 200 Hz and f _3s = 300 Hz - for the considered illustrative example of ShSTO 14, presented as a power electric transformer, mounted in the technical room 1 of ETPZT ), differing from their values, at least not less than 1.06 times, as it is represented in expressions (8) ... (13):

рабочей доминирующей функциональной частоты (трех кратных доминирующих частотных гармоник -

) звукового излучения ШГТО 14, укладывающихся в ограничительных пределах габаритного параметра A (L, В, Н), характеризующего размеры внутреннего пространства внутренней трехмерной воздушной полости 13.where n _vs is an integer (natural number) of half-lengths of sound waves

working dominant functional frequency (three multiple dominant frequency harmonics -

) sound radiation SHGTO 14, stacked in the limiting limits of the overall parameter A (L, B, H), which characterizes the size of the internal space of the internal three-dimensional air cavity 13.

, излучаемых на дискретных значениях рабочих доминирующих функциональных частот гармонических составляющих спектра f_ms (f_1s, f_2s, f_3s) ШГТО 14, базируется на достижении величины приемлемого рассогласующего смещения частотно-волновых резонансных совпадений значений

относительно m⋅λ_mA, укладывающихся в ограничительных пределах габаритного параметра А, при обеспечении ослабления резонансного значения акустического отклика на величину, равную 15 дБ. С другой стороны, величина приемлемого рассогласующего смещения частотно-волновых резонансных совпадений значений

относительно m⋅λ_mA, укладывающихся в ограничительных пределах габаритного параметра А, предопределяется необходимостью исключения возникновения физического процесса биений взаимодействующих акустических сигналов (звуковых волн) с близкими значениями частот звуковых колебаний f_ms и f_mA. На фиг. 16.1 представлен пример экспериментально замеренного резонансного возрастания УЗД, представленного в виде «резонансного акустического отклика» на выраженной энергоемкой первой собственной акустической моде с дискретным значением частоты собственных звуковых колебаний f_1L массо-упругого тела воздушного объема, заключенного во внутреннем пространстве (внутренней трехмерной воздушной полости 13) исследуемого технического помещения 1, оборудованного жесткими звукоотражающими стенами, в направлении габаритного размера L, равного 4 м. В частности, зарегистрирован измерительными средствами (измерительным микрофоном и измерительным усилителем-анализатором), вышеуказанный «резонансный акустический отклик» на частоте собственных звуковых колебаний f_1L=43 Гц массо-упругого воздушного объема, с собственной акустической модой внутренней трехмерной воздушной полости 13 исследуемого технического помещения 1, характеризуется соответствующей длиной собственной звуковой волны λ_1L, равной 8 м

, при температуре воздуха t=20°C.The rationale for the choice of the limiting ratios of the overall parameters A (L, B, H) of the internal three-dimensional air cavity 13 of the technical room 1 is not less than 1.06 times, in relation to the values of multiple products of half-lengths of sound waves

emitted at discrete values of the operating dominant functional frequencies of the harmonic components of the spectrum f _ms (f _1s , f _2s , f _3s ) of the NGTU 14, is based on the achievement of an acceptable mismatch value of the frequency-wave resonance coincidences of values

with respect to m⋅λ _mA , within the limiting limits of the overall parameter A, while ensuring the attenuation of the resonant value of the acoustic response by an amount equal to 15 dB. On the other hand, the magnitude of the acceptable discordant shift of the frequency-wave resonance coincidence of values

with respect to m⋅λ _mA , which fall within the bounding limits of the overall parameter A, is determined by the need to exclude the occurrence of the physical process of the beating of interacting acoustic signals (sound waves) with close values of the frequencies of sound vibrations f _ms and f _mA . FIG. 16.1 shows an example of an experimentally measured resonant increase in ultrasonic sounding presented as a “resonant acoustic response” on a pronounced energy-intensive first intrinsic acoustic mode with a discrete value of the natural acoustic frequency f _{1L of the} mass-elastic body of air volume enclosed in the inner space ) the investigated technical premises 1, equipped with rigid sound-reflecting walls, in the direction of the overall size L, equal to 4 m. tnosti is registered measuring means (the measuring microphone and the measuring amplifier analyzer), the above "resonant acoustic response" to the natural frequency of the sound vibrations f _1L = 43 Hz weight and the elastic hollow space, with its own acoustic mode inside the three-dimensional air cavity 13 investigated the technical room 1 characterized by the corresponding length of its own sound wave λ _1L , equal to 8 m

, at air temperature t = 20 ° C.

Selecting reasonable ranges of values of the critical bands invalid (unwanted) matches the wave Δλ _1L based on the registered specific characteristics Q Q _a natural acoustic resonance inside the air cavity 13 of a three-dimensional technical room 1. To this effect, the degree of attenuation determined by the registered "resonant acoustic response", which manifests itself in the form of the maximum value of the ultrasonic sounding of the own acoustic mode recorded by instrumental measuring instruments, with its subsequent attenuation by an amount equal to 15 dB (5.6 times in linear units). The calculated critical range of unacceptable wave coincidences Δλ _1L , as shown in FIG. 16.1, in this case it is equal to 0.85 m, which differs from the sound wavelength of the own acoustic longitudinal mode λ _1L (0.11 λ _1L ). As appears from the description of the application as reference information in FIG. 21 diagrams of the energy addition (subtraction) of two incoherent ultrasound sources in logarithmic units (dB) presented in source [9] on page 27, the selected attenuation degree of the recorded “resonant acoustic response” of the ultrasonic sound is sufficient weak radiated SPL, less than 15 dB compared to more intense ultrasound, radiated sound source, does not have any significant effect (less than 0.1 dB) on the total sound pressure level in dB and is, in fact, disconnected from the resulting total sound field (see also sound spectra containing discrete dominant frequencies f _ms and f _ma , shown in Fig. 1, 2, 3, 4, 6, 9).

FIG. 16.2 and 16.3 illustrative examples of measured “resonant acoustic responses” of ultrasonic sounding on the first natural acoustic modes with discrete values of the natural sound oscillations f _1B and f _1L mass-elastic body of the air volume contained in the internal space (internal three-dimensional air cavity 13) of the technical premises 1, equipped with rigid sound-reflecting walls, in the direction of its width (overall dimension B), equal to 2 m, and its length (overall dimension L), equal to 5 m. Braz, certain range of values of critical bands unacceptable wave matches Δλ _1B and Δλ _1L (pos. 4) of the respective lengths λ _1B own sound waves (0,043λ _1B) and λ _1L (0,09λ _1L), in these cases amounted to 0.043 and 0 09

FIG. 16.4 shows an example of a measured “resonant acoustic response” of ultrasonic ultrasound on the third intrinsic acoustic mode with a discrete value of the natural vibration frequency f _{3B of the} mass-elastic body of air volume enclosed in the internal space (internal three-dimensional air cavity 13) of the technical room 1 under study, equipped with rigid sound reflecting walls, in the direction of its width (overall size B), equal to 4 m. A certain range of values of the critical range of unacceptable wave coincidence eny Δλ _3B (pos. 4) corresponding private sound wavelength λ _3B (0,04λ _3B) and λ _1L, in this case was 0.04.

звуковых волн, излучаемых ШГТО 14, на дискретных значениях рабочих доминирующих функциональных частот гармонических составляющих звукового спектра f_ms (f_1s, f_2s, f_3s), излучаемого ШГТО 14, составят величины, приведенные в выражениях (8)…(13).Taking into account the insignificant degree of influence on the physical processes of radiation, absorption and reflection of sound waves (α _rev <0.05) emitted by the ShGTO 14 in the airspace (internal three-dimensional air cavity 13) of the technical room 1, due to the use of typical structural materials of enclosing structures technical room 1, forming a rigid sound-reflecting wall elements, as well as technological tolerances in their manufacture, the possible allowable temperature fluctuations of air in the internal three-dimensional air polo five technical premises 13 1 and to ensure the efficient functioning of the claimed technical device - field values of the critical bands invalid (unwanted) matches the wave _{Δλ mA (Δλ mL, Δλ mB} , Δλ mH) - pos. 4 shall be taken as equal to 0.12. Accepted values of Δλ _mA (Δλ _mL , Δλ _mB , Δλ _mH ) - pos. 4, allows to avoid the occurrence of a physical phenomenon of “beats of sound vibrations” with similar frequencies of interacting sound vibrations, manifested as periodic amplifications and weaknesses of ultrasonic sounding with a difference in the frequencies of interacting sound vibrations that increase the unpleasant irritating effect on the human ear by the subjective perception of sound. Thus, the boundary values of the ratios of the overall parameters A (L, B, H) of the internal three-dimensional air cavity 13 of the technical room 1, to the multiple product of half the length

the sound waves emitted by ShGTO 14 at discrete values of the operating dominant functional frequencies of the harmonic components of the sound spectrum f _ms (f _1s , f _2s , f _3s ) emitted by ShGTO 14 will be the values given in expressions (8) ... (13).

звуковых волн, излучаемых ШГТО 14, смонтированном в техническом помещении 1, с габаритными размерами А (длиной L, шириной В и высотой Н) внутренней трехмерной воздушной полости 13 технического помещения 1, предотвращающие развитие физического процесса резонансного усиления звукового излучения в пространстве внутренней трехмерной воздушной полости 13 технического помещения 1, в том числе и в широком эксплуатационном температурном диапазоне воздуха в техническом помещении 1 от -20 до +40°C.As an illustrative example, the following are the results of certain ranges of values of the critical ranges of unacceptable wave coincidences Δλ _mA (Δλ _mL , Δλ _mB and Δλ _mH ) - pos. 4, which can be used to implement the effective mismatch of invalid (unwanted) multiple coincidences of half lengths

sound waves emitted by ShGTO 14, mounted in the technical room 1, with overall dimensions A (length L, width B and height H) of the internal three-dimensional air cavity 13 of the technical room 1, preventing the development of the physical process of resonant amplification of sound radiation in the space of the internal three-dimensional air cavity 13 technical rooms 1, including in a wide operational temperature range of air in the technical room 1 from -20 to + 40 ° C.

звуковых волн на дискретных значениях рабочих доминирующих функциональных частот f_ms трех гармонических составляющих спектра звукового излучения (f_1s, f_2s, f_3s), производимого ШГТО 14 (в данном конкретном случае, на примере силового электротрансформатора), проявляющегося в виде специфического низкочастотного «трансформаторного гула», при изменении значений эксплуатационных температур воздуха в пространстве внутренней трехмерной воздушной полости 13 технического помещения 1 в диапазоне от -20°C до +40°C.Table 1, in particular, presents the calculated half-length values

sound waves at discrete values of the working dominant functional frequencies f _{ms of the} three harmonic components of the spectrum of sound radiation (f _1s , f _2s , f _3s ) produced by SRTG 14 (in this particular case, using the example of a power electric transformer), manifested as a specific low-frequency "transformer hum, ”when changing the values of operating air temperatures in the space of the internal three-dimensional air cavity 13 of the technical room 1 in the range from -20 ° C to + 40 ° C.

звуковых волн на 0,06…0,18 м (на 11%) при таком существенном изменении эксплуатационной температуры воздуха на 60°C (от -20°C до +40°C).Analysis of the results of table 1 indicates an increase in the values of

sound waves at 0.06 ... 0.18 m (11%) with such a significant change in operating air temperature at 60 ° C (from -20 ° C to + 40 ° C).

звуковых волн, излучаемых ШГТО 14 с заданными габаритными размерами A (L, В, Н) внутренней трехмерной воздушной полости 13 технического помещения 1 (представленного в данном случае ЭТПЗТ), в диапазоне изменения эксплуатационных температур воздуха в нем, при достижении дискретных значений -20°C, 0°C, +20°C и +40°C.Table 2 presents the calculated range of values of the critical ranges Δλ _mA (Δλ _1A , Δλ _2A , Δλ _3A ) - pos. 4, which according to the description and the first claim of the invention can be used to effectively influence the physical process of mismatch of multiple coincidences of half-lengths

sound waves emitted by ShGTO 14 with given dimensions A (L, B, H) of the internal three-dimensional air cavity 13 of the technical room 1 (ETPZT presented in this case), in the range of variation of the operating air temperature in it, when the discrete values of -20 ° are reached C, 0 ° C, + 20 ° C and + 40 ° C.

Analysis of the results of table 2 indicates specific values of the parameter Δλ _mA (pos. 4), which should be taken into account and excluded, as causing additional negative resonant acoustic radiation, taken from the design (modernization) dimensions A (L, B, H) internal three-dimensional air cavity 13 technical room 1.

Thus, based on the analysis of the calculated regions of the values of the critical ranges Δλ _mA (Δλ _1A , Δλ _2A , Δλ _3A ) - pos. 4, given in Table 2, it follows that in order to exclude (effective suppression) negative resonant amplification of sound radiation and exclude the occurrence of a physical process of beating of interacting acoustic signals (sound waves) with close values of frequencies of sound oscillations f _ms and f _mA in the internal three-dimensional air cavity 13 technical room 1, presented, in particular ETPZT, it is necessary that the critical ranges Δλ _mA (Δλ _1A , Δλ _2A , Δλ _3A ) - pos. 4, with a significant change in operating air temperatures in the working area (internal three-dimensional air cavity 13) of the technical room 1 at 60 ° C (from -20 to + 40 ° C) were within the specified limited limits of overall values:

(λ_1s, λ_2s, λ_3s) звуковых волн, излучаемых ШГТО 14 во внутренней трехмерной воздушной полости 13 габаритными размерами A (L, В, Н) технического помещения 1 (в приведенном выше иллюстративном примере - ЭТПЗТ).To effectively prevent the development of the physical process of negative resonant amplification of sound vibrations of a mass-elastic body of air volume concentrated in the space of an internal three-dimensional air cavity 13 of a technical room 1, and to prevent the occurrence of a physical beat process of interacting acoustic signals (sound waves) with close frequencies of sound vibrations f _ms and f _mA, it is necessary that dimensions A (L, B, H) which characterize the three-dimensional internal space aeronautical field STI 13 technical room 1 does not fall into the above defined, according to the calculated values of the expression (14), a specific dimensional range of values of critical bands Δλ _mA (pos. 4) invalid coincidence frequency wave used for the effective half-lengths mismatch multiple coincidences

(λ _1s , λ _2s , λ _3s ) of sound waves emitted by ShGTO 14 in the internal three-dimensional air cavity 13 with overall dimensions A (L, B, H) of the technical room 1 (in the above illustrative example - ETPZT).

It is necessary to indicate possible additional implementations of the proposed technical device, including the implementation of forced stabilization of air temperature (stabilized temperature field parameters) in the internal three-dimensional air cavity 13 of the technical room 1, represented by ETPZT, in narrower operating temperature ranges (for example, variant versions with additionally mounted technical devices of automatic temperature control), in which the specified areas are The critical ranges Δλ _mA (pos. 4) can be narrowed accordingly (located in narrower ranges of values). This will allow, if necessary, to realize an expanded range of overall dimensions A of the internal three-dimensional air cavity 13 of the technical room 1, which are guaranteed not falling within the stated dimensional range of values of the critical ranges Δλ _mA (pos. 4).

Effective evaluation criterion for achieving low noise (providing higher “acoustic quality”) of technical room 1, from the point of view of excluding (effective attenuation) of dynamic excitation of resonant acoustic oscillations of a mass-elastic body of an air volume of an internal three-dimensional air cavity 13 of a technical room 1 by the amount of attenuation “ acoustic resonance response ", equal to 15 dB, according to the estimated physical parameter" quality of own acoustic resonance a three-dimensional internal air cavity technical facilities - Q _a », in view of the experimental results shown in FIG. 16.1, 16.2, 16.3, 16.4, should be considered compliance with the requirements in accordance with the above expressions (15) and (16):

, характеризуемых соответствующими дискретными значениями собственных частот звуковых колебаний f_mA (f_mL, f_mB, f_mH), удовлетворяющим условиям исключения (эффективного ослабления) развития физического процесса резонансного усиления излучения звуковых колебаний и возникновения физического процесса биений взаимодействующих акустических сигналов (звуковых волн) с близкими значениями частот звуковых колебаний f_ms и f_mA в пространстве внутренней трехмерной воздушной полости 13, в которой размещен ШГТО 14, производящий звуковое излучение с заданными дискретными значениями рабочих доминирующих функциональных частот звуковых колебаний, представленных гармоническими составляющими спектра звукового излучения f_ms (f_1s, f_2s, f_3s) ШГТО 14 и характеризуемых полудлинами звуковых волн

, определяемый согласно выражению (17):where, K _mA (K _mL , K _mB , K _mH ) is the multiplicity factor of the established ratios of the dimensions A of the internal three-dimensional air cavity 13 (its length L, width B and height H), with corresponding numerical values within their limited spatial directions half-lengths of the intrinsic sound waves of the lower intrinsic acoustic modes, represented by the intrinsic acoustic oscillations of the mass-elastic body of air volume contained in the internal three-dimensional air cavity 13 -

characterized by the corresponding discrete values of the eigenfrequencies of sound vibrations f _mA (f _mL , f _mB , f _mH ) satisfying the conditions for eliminating (effective attenuation) the development of the physical process of resonant amplification of the radiation of sound vibrations and the occurrence of the physical process of beating interacting acoustic signals similar values of the frequencies of sound oscillations f _ms and f _mA in the space of the internal three-dimensional air cavity 13, in which the ShGTO 14 is located, producing sound radiation from the rear these discrete values of the working dominant functional frequencies of sound vibrations, represented by the harmonic components of the spectrum of sound radiation f _ms (f _1s , f _2s , f _3s ) of BGPT 14 and characterized by half-lengths of sound waves

determined according to expression (17):

where, λ _ms (λ _1s , λ _2s , λ _3s ) is the sound wavelength (sound wavelengths) of the working dominant functional frequency f _ms (three multiple of the lower dominant frequency harmonics - f _1s , f _2s , f _3s ) of the sound radiation of the ShSTO 14 , m;

K _t is the reduced temperature coefficient of correction of the speed of sound c (t) and the sound wavelength λ _ms emitted by ShGTO 14 in a given allowable (recommended) operating operational range Δt ° C of the change in air temperature in the space of the internal three-dimensional air cavity 13 of the technical room 1, determined according to expression (18):

where λ _{mA20 ° C} is the sound wavelengths of lower intrinsic acoustic modes, represented by the intrinsic acoustic oscillations of the mass-elastic body of air volume enclosed in the space of the internal three-dimensional air cavity 13, with the compared basic air temperature value t ° C equal to + 20 ° C ;

λ _{mAt ° C} is the sound wavelengths of the lowest natural acoustic modes, represented by the natural acoustic oscillations of the mass-elastic body of the air volume enclosed in the space of the internal three-dimensional air cavity 13, at the operating steady-state (temperature-controlled) value of the air temperature t ° C;

Table 3, as a reference, shows the values of the reduced temperature coefficient for correcting the speed of sound c (t) and the sound wavelength λ _ms -K _t , in the range of the established operating air temperatures in the internal three-dimensional air cavity 13 when the discrete values of -20 are reached ° C, 0 ° C, + 20 ° C and + 40 ° C.

, излучаемых ШГТО 14, находящегося в заданными габаритными размерами A (L, В или Н) внутренней трехмерной воздушной полости 13 технического помещения 1. Как следует из анализа представленных на фиг. 17 иллюстративных примеров, такой выбор величины габаритного размера A (L, В или Н) внутренней трехмерной воздушной полости 13 технического помещения 1, приводящий к нежелательному негативному интенсивному динамическому возбуждению резонансных акустических колебаний массо-упругого тела, заключенного во внутренней трехмерной воздушной полости 13 технического помещения 1, вызывает ухудшение безопасностных акустических (шумокомфортных) качеств воздушной среды внутри технического помещения 1 и обуславливает повышенную передачу «паразитного» шумового излучения в прилегающие (смежные) помещения строительного здания и/или в открытое окружающее внешнее пространство.FIG. 17 presents illustrative examples of sound pressure plots on the excited lower eigen (resonant) acoustic modes (pos. 15) that are formed in the space of the internal three-dimensional air cavity 13 of the technical room 1, corresponding to discrete values of their own frequencies of sound vibrations f _mA (f _mL , f _mB , f _mH ), compiled in spatial directions of overall dimensions A (length L, width B and height H) of an internal three-dimensional air cavity 13, with the variants of finding the given overall dimensions of an internal third Δλ _mA (Δλ _mL , Δλ _mB , Δλ _mH ) - pos. 13 air compartment 13 of the technical room 1 A (L, B, H) in the area of the ranges of the critical range (critical ranges) of unacceptable (unwanted) wave matches. 4, providing negative intensive development of the physical process, realized due to multiple coincidences of half-lengths of sound waves

, emitted by the ShGTO 14, located in the given dimensions A (L, B or H) of the internal three-dimensional air cavity 13 of the technical room 1. As follows from the analysis shown in FIG. 17 illustrative examples, such a choice of the size of the overall size A (L, B or H) of the internal three-dimensional air cavity 13 of the technical room 1, resulting in undesirable negative intensive dynamic excitation of resonant acoustic oscillations of a mass-elastic body contained in the internal three-dimensional air cavity 13 of the technical room 1, causes a deterioration in the safety acoustic (noise-comfort) qualities of the air environment inside the technical room 1 and causes an increased transmission of “parasitic о ”noise radiation in adjacent (adjacent) premises of a building building and / or in an open surrounding external space.

звуковых волн, излучаемых ШГТО 14, с габаритным размером A (L, В или Н) пространства внутренней трехмерной воздушной полости 13 технического помещения 1. Как следует из представленных на фиг. 18-19 иллюстративных примеров, такой выбор габаритного размера A (L, В или Н) пространства внутренней трехмерной воздушной полости 13 технического помещения 1 указывает на эффективное исключение резонансного динамического возбуждения акустических колебаний массо-упругого тела воздушного объема внутренней трехмерной воздушной полости 13 технического помещения 1, или же потенциальная возможность к указанному резонансному усилению звукового излучения собственных резонансных акустических мод массо-упругого тела воздушного объема, заключенного в пространстве внутренней трехмерной воздушной полости 13 технического помещения 1, в этом случае, существенно ослабляется.FIG. 18-19, illustrative examples are presented depicting sound pressure plots at lower natural (resonant) acoustic modes 15 excited in the space of an internal three-dimensional air cavity 13 of a technical room 1 at discrete values of the natural frequencies of sound vibrations f _mA (f _mL , f _mB , f _mH ), composed in the spatial directions of the overall dimensions A (length L, width B and height H) of the space of the internal three-dimensional air cavity 13, with the variants of finding the specified overall dimensions of the internal three-dimensional the air cavity 13 the technical room 1 A (L, B, H) the areas outside the critical range of values (critical ranges) invalid (unwanted) matches the wave _{Δλ mA (Δλ mL, Δλ mL} , Δλ mH) - pos. 4, providing positive exclusion (effective mismatch) of the development of the physical process of amplification of sound radiation and the emergence of the physical process of beating interacting acoustic signals (sound waves) with close values of the frequencies of sound oscillations f _ms and f _mA due to the realized multiple mismatches of half lengths

sound waves emitted by the ShGTO 14, with the overall size A (L, B or H) of the space of the internal three-dimensional air cavity 13 of the technical room 1. As follows from the figures shown in FIG. 18-19 illustrative examples, such a choice of the overall size A (L, B or H) of the space of the internal three-dimensional air cavity 13 of the technical room 1 indicates the effective exclusion of resonant dynamic excitation of acoustic oscillations of the mass-elastic body of the air volume of the internal three-dimensional air cavity 13 of the technical room 1 or the potential possibility for the specified resonant amplification of sound radiation of the own resonant acoustic modes of a mass-elastic body of air volume is concluded th three-dimensional in the space inside the air cavity 13 the technical room 1, in this case, significantly attenuated.

звуковых волн, излучаемых ШГТО 14, в направлении ее габаритных размеров L и В. Заштрихованные области иллюстрируют соответствующие зоны областей значений критического диапазона (критических диапазонов) Δλ_mL (поз. 4). Как следует, в частности, из представленных на фиг. 20 вариантных конструктивных исполнений технических помещений 1, в зависимости от выбора конкретных габаритных размеров внутренней трехмерной воздушной полости 13 L, 2L и 3L, в этих случаях может развиваться (или исключаться) физический процесс негативного резонансного усиления звукового излучения на собственных резонансных акустических модах массо-упругого тела воздушного объема, заключенного в пространстве внутренней трехмерной воздушной полости 13 технического помещения 1.FIG. 20 shows an illustrative two-dimensional image of variant designs of the technical room 1, with dimensions A of the internal three-dimensional air cavity 13 in the spatial directions L and B, in which corresponding lower intrinsic acoustic modes characterized by sound wavelengths λ _mL and λ _mB in the internal three-dimensional are formed. the air cavity 13 in the technical room 1 discrete values of the natural frequencies of sound vibrations f _mL and f _mB, to fit into the space VNU renney dimensional air cavity 13 different integer (natural number) n _vs half-lengths

sound waves emitted by the ShGTO 14, in the direction of its overall dimensions L and B. The hatched areas illustrate the corresponding zones of the ranges of values of the critical range (critical ranges) Δλ _mL (pos. 4). As follows, in particular, from those shown in FIG. 20 variant designs of technical rooms 1, depending on the choice of specific dimensions of the internal three-dimensional air cavity 13 L, 2L and 3L, in these cases the physical process of negative resonant amplification of sound radiation on its own resonant acoustic modes of mass-elastic may develop (or be excluded) the body of the air volume enclosed in the space of the internal three-dimensional air cavity 13 of the technical room 1.

Thus, the essence of the claimed invention lies in the fact that in the technical room 1, containing supporting fencing rigid sound reflecting elements in the form of walls 7, 8, 11, ceiling 5, floor 6, doorway 9 with the entrance door 10 closed, inlet and exhaust ventilation openings 12, forming an internal three-dimensional air cavity 13, represented by a rectangular parallelepiped with overall dimensions A (L⋅B⋅H), characterized by the physical parameters of the sound and temperature field f _mA , λ _mA , s, t ° C, in which m mounted at least one operating SHGTO 14 operating at a given steady-state operating speed n _s , accompanied by physical processes of radiation of sound and thermal energy, the spectral sound composition of which contains prominent discrete values of the working dominant functional frequencies f _ms , characterized by the corresponding sound wavelengths λ _ms , while at least one of the overall parameters A of the internal three-dimensional air cavity 13 is presented The rectangular parallelepiped with the overall dimensions L⋅B⋅H satisfies the requirements of the interrelated ratio of the parameters of the established high-speed operational mode of operation n _s ШГТО 14, accompanied and characterized by the physical characteristics of the sound and temperature fields of the internal three-dimensional air cavity 13 of the technical room 1, defined according to the expression ( nineteen):

Thus, when developing a low-noise technical room 1, with ShGTO 14 mounted in it, according to the proposed technical solution, it is necessary to take into account (select) a given (passport) steady-state high-speed operating mode of ShGTO 14, with corresponding discrete values of operating dominant functional frequencies f _ms (f _1s , f _2s , f _3s ) of the sound radiation of the ShGTO 14, determined by calculation or experimentally. In such cases, it is possible to implement physical conditions that ensure the elimination of the negative development of the physical process of dynamic excitation and resonant amplification of sound radiation at discrete values of the operating dominant functional frequencies f _{ms of} sound radiation of ShGTO 14 interacting with the frequency-modal characteristics of a mass-elastic body of an internal three-dimensional air cavity 13 technical room 1. Depending on the known (determined by calculation or experimentally) discrete values The main operating frequencies f _{ms of the} sound radiation of the ShGTO 14, mounted in the technical room 1, are taken into account (the choice is made at the stage of developing technical documentation for the technical room 1) given the dimensions A of the internal three-dimensional air cavity 13 (length L, width B height H). The specified technical procedure can be provided, at least in relation to one of its overall parameters A (L, B, H). In some cases, this may be sufficient to obtain an acceptable effect of improving the acoustic quality of the technical room 1 according to the technical specifications for its design or technical conditions of operation. In this case, it is possible to realize the effect of improving the acoustic quality of the technical room 1, in at least one of the spatial directions of the internal three-dimensional air cavity 13 of the technical room 1, when its lower acoustic modes are λ _mA (λ _mL , λ _mB , λ _mH ), with the discrete values of the natural frequencies of sound vibrations _{f mA (f mL, f mB} , f mH), defined in said spatial direction a (L, B, H), do not enter into a resonant acoustic interaction with the known values of the dominant working function ionalnyh frequency f _ms sound radiation SHGTO 14. In this case, it is necessary to take into account the physical parameters of temperature field in the space formed inside the air cavity 13 of a three-dimensional technical room 1, affecting the velocity of propagation of sound waves with acoustic waves and length λ and thus, on the field the values of the critical ranges Δλ _mA (Δλ _mL , Δλ _mB , Δλ _mH ) - pos. 4, in order to ensure the elimination (non-admission) of the development of the physical process of multiple coincidences of half-lengths λ _{mS of} sound waves emitted by ShGTO 14 mounted in an internal three-dimensional air cavity 13 with overall dimensions A (L, B, H) of the technical room 1.

Ultimately, the implementation of the proposed technical solution eliminates (minimizes) the time, material, labor and cost costs associated both with the forced degree of the required structural and technological impact on the improvement of the acoustic characteristics of the ShGTO 14, and on the improvement of the acoustic characteristics of wall structures and noise-suppressing elements used as part of a typical design of a technical room 1, solely at the expense of the proposed corresponding advanced update themselves performance (selection) of predetermined internal dimensions of the cavity 13 a three-dimensional air technical room 1.

Depending on the specific target tasks of the design specification and / or technical conditions of operation of the technical room 1, the implementation of the proposed technical solution may include as the elimination of the maximum number of manifesting air acoustic cavity resonances excited in all spatial directions of the internal three-dimensional air cavity 13 of the technical room 1, and may provide for a limited number of airway acoustic resonances, which manifest themselves in separate spatial directions of the internal three-dimensional air cavity 13 of the technical room 1. Such a choice can be predetermined, for example, for the most intensely manifested air acoustic cavity resonances, characterized by the highest values of ultrasonic sounding, requiring a priority solution to the technical problem considered. Some of the internal spatial air cavities 13 of the technical room 1 excited in space of the technical room 1 of the eigen acoustic modes λ _mA (λ _mL , λ _mB , λ _mH ) with the frequencies of sound oscillations f _mA (f _mL , f _mB , f _mH ) may have weakly expressed amplitude resonant acoustic feedback (quality factor Q _a natural acoustic resonance inside the three-dimensional cavity 13, which air is sufficiently low) recorded in the sound pressure spectra. As a result, they, for example, can be completely or partially masked by “extraneous” sound radiation from other GDTs 14. Given the additional technical and material costs that arise, such natural acoustic modes can no longer be taken into account in certain variant versions of the low-noise technical room 1, which is reflected in the first independent claim. Also, prevention, with the achievement of the complete elimination (effective attenuation) of acoustic resonant excitation of the maximum number of resonant acoustic modes of a mass-elastic body contained in the internal three-dimensional air cavity 13 of the technical room 1, may be considered impractical due to the excessive (unjustified) complication of the solution of this type of technical (operational) and / or value task.

) звуковых волн. В этих случаях возникают возможности предотвращения (эффективного подавления) воздушных полостных акустических резонансов во внутренней трехмерной воздушной полости 13 технического помещения 1, с образующимися акустическими и температурными полями. Возможно также и решение поставленной технической задачи за счет обозначенного в первом пункте формулы изобретения, использования модернизированного ШГТО 14, с преднамеренно измененными паспортными техническими параметрами, для последующего монтажа такого ШГТО 14, с его измененным скоростным эксплуатационным режимом работы n_s, с соответствующим сопутствующим изменением дискретных значений рабочих доминирующих функциональных частот f_ms и длин звуковых волн λ_ms. В этом случае конструктивные параметры A (L, В, Н) технического помещения 1 остаются неизменными, что может быть предпочтительным при проведении процесса модернизации технического объекта. Также не исключен вариант решения поставленной технической задачи за счет одновременного совместного введения изменения технических и физических параметров как в составе конструкций технического помещения 1, так и ШГТО 14 (параметры A, f_mA, λ_mA, с, t°C, Δt°C, K_t, n_s, λ_ms, n_vs), позволяющего достигать результирующего эффекта предотвращения (устранения) развития физического процесса резонансного акустического излучения и исключения возникновения физического процесса биений взаимодействующих акустических сигналов (звуковых волн) с близкими значениями частот звуковых колебаний f_ms и f_mA за счет заданного преднамеренного рассогласования частотно-модальных характеристик звуковых излучений ШГТО 14 и частотно-модальных характеристик массо-упругого тела, заключенного во внутренней трехмерной воздушной полости 13 технического помещения 1, габаритных размеров A (L, В, Н).The implementation of the proposed technical solution can occur at the initial stages of designing a low-noise technical room 1, with a choice of given dimensions A (L⋅B⋅H), taking into account the known passport technical parameters of the SHGTO 14 mounted in it, operating at a given constant speed operational (passport) mode of operation SSTO (n _s ), accompanied by a corresponding physical process of emission of sound energy, in the spectral composition of which there are known (determined by calculation or experiment in an ideal way) discrete values of the working dominant functional frequencies f _ms , with corresponding lengths λ _ms (half-lengths

a) sound waves. In these cases, it becomes possible to prevent (effective suppression) of air cavity cavities in the internal three-dimensional air cavity 13 of the technical room 1, with the resulting acoustic and temperature fields. It is also possible to solve the technical problem due to the use of the upgraded ShGTO 14, with intentionally modified passport technical parameters, for the subsequent installation of such ShGTO 14, with its modified high-speed operating mode n _s , with a corresponding accompanying change of discrete the values of the working dominant functional frequencies f _ms and sound wavelengths λ _ms . In this case, the design parameters A (L, B, H) of technical room 1 remain unchanged, which may be preferable when carrying out the process of modernization of a technical object. Also, there is a possibility of solving a technical problem due to the simultaneous simultaneous introduction of changes in technical and physical parameters both in the structure of the technical room 1 and in the ShGTO 14 (parameters A, f _mA , λ _mA , s, t ° C, Δt ° C, K _t , n _s , λ _ms , n _vs ), which allows to achieve the resultant effect of preventing (eliminating) the development of the physical process of resonant acoustic radiation and eliminating the onset of the physical process of beating interacting acoustic signals (sound waves) with close values the frequency of sound oscillations f _ms and f _mA due to the predetermined deliberate mismatch of the frequency-modal characteristics of the sound radiation of ShGTO 14 and the frequency-modal characteristics of the mass-elastic body contained in the internal three-dimensional air cavity 13 of the technical room 1, overall dimensions A (L, B , H).

Claims (14)

Low-noise technical room containing supporting fencing elements in the form of walls, ceiling, floor, doorway with the door closed, intake and exhaust ventilation openings forming an internal three-dimensional air cavity represented by a rectangular parallelepiped with overall dimensions LB⋅H, characterized by physical dimensions established in it sound and temperature field parameters f _mA , λ _mA , s, t ° C, in which at least one operated noise-generating technical object is installed, operating on given steady-state operating speed n _s , accompanied by physical processes of radiation of sound and thermal energy, the spectral sound composition of which contains prominent discrete values of the working dominant functional frequencies f _ms , characterized by corresponding sound wavelengths λ _ms , characterized in that, at least , one of the overall parameters of the internal three-dimensional air cavity A, represented by a rectangular parallelepiped with overall dimensions L⋅B⋅H, meets the requirements of an interconnected ratio at a given steady-state operating speed of n _s noise-generating technical object with the physical parameters of the sound and temperature field, which are determined by the expression:

where A is one of the overall parameters (L, B, H), characterizing the dimensions of the internal three-dimensional air cavity of the technical room, m; λ _ms - sound wavelength of the working dominant functional frequency f _{ms of} sound radiation of a noise-generating technical object at a given steady-state high-speed operational mode of operation n _s , m; n _s is a given steady-state high-speed operational mode of operation of a noise-generating technical object, characterized by operating dominant functional frequencies f _ms , min ^-1 , s ^-1 ; n _vs is an integer (natural number) half-length

sound waves of the working dominant functional frequency f _{ms of} sound radiation of a noise-generating technical object that falls within the limiting limits of the overall parameter A, characterizing the overall dimensions of the internal three-dimensional air cavity of the technical room (L, B, H); f _ms - working dominant functional frequency of sound radiation of a noise-generating technical object, Hz; K _t is the temperature coefficient of correction of the speed of sound with and the sound wavelength λ _{ms of the} working dominant functional frequency f _ms emitted by the noise-generating technical object, at a given steady-state high-speed operating mode n _s , in the operational range of air temperature variation Δt ° C in the internal three-dimensional air technical room cavities (L, B, H); f _mA - discrete values of the natural frequencies of sound vibrations with the emerging natural acoustic modes of the mass-elastic body of the air volume of the internal three-dimensional air cavity of the technical room, distributed in the spatial directions of its overall parameters (L, H, H), Hz; λ _mA is the sound wavelengths of the lower proper acoustic modes, represented by the own acoustic oscillations of the mass-elastic body of the air volume of the internal three-dimensional air cavity of the technical room, m; c is the speed of propagation of sound waves in the air environment of the internal three-dimensional air cavity of the technical room, m / s; t ° C is the air temperature in the internal three-dimensional air cavity of the technical room, ° C; Δt ° C is the allowable (recommended, passport) operating operational range of changes in air temperature in the internal three-dimensional air cavity of a technical room, ° C; L, B, H - respectively, the length, width and height of the internal three-dimensional air cavity of the technical room, m.

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