CN1177792A - Fluidic element structure body for controlling noise and vibration, and control method thereof - Google Patents
Fluidic element structure body for controlling noise and vibration, and control method thereof Download PDFInfo
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- CN1177792A CN1177792A CN 97118467 CN97118467A CN1177792A CN 1177792 A CN1177792 A CN 1177792A CN 97118467 CN97118467 CN 97118467 CN 97118467 A CN97118467 A CN 97118467A CN 1177792 A CN1177792 A CN 1177792A
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Abstract
Fluidic constructs, including grouped stacks of fluidic elements, that provide countersound to control sound in a noisy environment, prevent radiation of sound from vibrating surfaces, reduce sound-induced vibration of surfaces, and absorb sound that might otherwise impact on surfaces, are provided. These constructs may have a wide range of geometries for specific applications, but generally include a face plate on one side, and a back plate on the other side. Supply ports on the back plate provide a supply of fluid that flows through the construct, while undergoing acoustic modulation through fluidic amplifiers. The face plate includes input ports that sense sound waves to be controlled. While output ports creats sound out of phase with the sound sensed by the input ports to substantially counteract noisy sound waves.
Description
The present invention relates to relevant noise attentuation field, and proposed a kind of structure, this structure has comprised the fluidic that can control the structure impedance, so that decay sound wave in a broad frequency range.
Developed at present the technology of multiple attenuate acoustic noise, wherein comprised, for example, used the passive type sound suppressor, these class methods have been used in the exhaust system of automobile.Also have some other technologies, be included in and use noise reduction cover around the device that sends noise and use the wave absorption material to reduce sound wave reverberation in the environment etc.In addition, by produce " noise elimination sound wave " with in and the active noise reduction technology of noise waves be proved to be success.For example, one carried out with microphone system's (microphone by power supply power supply) of noise detection is same to produce that the system that offsets ripple links to each other (loudspeaker is by the power supply power supply) and the active noise reduction system that forms successfully is applied in the propeller driver aircraft cabin with loudspeaker, electronics microphone-speaker system need distribute a plurality of microphones and loudspeaker apparatus along machinery space bulkhead, and is only limited to attenuate acoustic noise in a very narrow frequency band range.This system is better by the periodicity acoustic pressure effect of the thruster generation of rotation for decay, but is not suitable for the broadband sound wave of the aerodynamic force boundary layer generation of decay jet engine or aircraft.
So need a kind of can be reliably and the device of decay sound wave in the frequency band range of broad economically, preferably need not to drop into a large amount of maintenances and can work long-term effectively under the situation of continuous monitoring need not.And have energy saving, and under the situation that need not the energy or seldom energy supply, work, in addition, this device should be saved the space, and volume can not be excessive, so that use in various application scenarios to the space requirement strictness.At last, this device should be very light, and it can be used under the application scenario of this class of aircraft cabin to weight sensitive.
The invention provides a kind of controllable, structure that acoustic impedance is low especially, the wideband noise in the environment of can decaying effectively.This structure can be made different shape, comprises being fit to the flat shape of using as wallpaper, the cylindrical shape that is applicable to sound suppressor, and is applicable to the shape that other noise reductions are used, and so this light in structure and approaching is save space very.And as long as this structure does not need to import electric energy with other energy and suitable gaseous state or the liquid pressure fluid of input.
The structure of this invention is formed by the array that a plurality of groups constitute, and has cut out fluidic on thin slice, and each fluidic sheet group includes a slice at least, and preferably multi-disc has the thin slice of fluid amplifier.These fluid amplifiers can be connected so that each thin slice can both amplify the acoustic pressure through the fluid of sheet group significantly.This fluidic architecture body also has at least one control mouthful (or a title " microphone ") and is positioned on the structure panel, this panel carries out in the environment of noise control towards needs, and the input that this control mouth is received is modulated to produce with the different sound wave of ambient sound waves phase place the fluid stream that enters structure from supply opening.What produced is this through amplifying and sound wave (noise elimination sound wave) that phase place is different sends and incident acoustic wave is controlled and decayed from least one outlet (or claim " loudspeaker ") self-structure body.Simultaneously, be emptied to a place enough far away in unwanted that part of at least one evacuation port from the fluidic array in the acoustic pressure after the amplification, so that it does not produce very big influence to attenuate acoustic noise work.
Need a passing time because the air supply arrives outlet by fluidic element structure body, therefore under high frequency situations, may in structure jet loop, problem of unstable take place.For offsetting this possibility, structure has comprised the sound wave low-pass filter of aperture and cavity (volume) form, with the elimination high frequency waves.
In a preferred embodiment, every " fluidic thin slice " made by the sheeting of the about 0.1mm to 0.5mm of thickness.Can use to comprise metal film, plastic sheet etc. are at interior a series of materials.A plurality of this thin slices that have fluid amplifier alternately are entrained with the thin slice of being with transport element therebetween, are combined into one " sheet group " of element.Controlling mobile or conduction at the transport element on the transport element thin slice at the fluid between the fluidic on the fluidic thin slice on two faces of this sheet.A plurality of fluidic sheet groups and transport element sheet group are combined " array " that has constituted the sheet group.According to the geometric properties of this array, constituted noise control " wallpaper " or the cylinder pillar sound suppressor in the embodiment of the invention, will do further detailed description to this below.
Because the structure of this invention may be required to customize to be fit to specific application scenario, so structure is made a series of different geometric formats, an every kind of geometric format and a specific application adapt.Among the embodiment as described herein, the form of the noise control structure body of this invention is a kind of " absorbing the wallpaper of sound wave ", wherein mainly comprises the plane jet element.A series of like this thin slices that have a plane jet element with a predetermined sequential organization together so that obtain the effect of desired attenuate acoustic noise.This noise reduction " wallpaper " can be used for various different occasions, the lining that comprises the sidewall that is used as aircraft cabin and other vehicles, be used for theater, recording studio, the opera Room with the processing sound equipment, and be used for the processing and manufacturing environment that some can produce the high-decibel noise that health is harmful to.
In another embodiment of the present invention, noise control structure body is roughly a cylindrical shape, and the thin slice that has fluidic is rolled into and is similar to the pell volume.The sound suppressor of the structure of this form as the fluid sound wave that passes through this structure axis hole.In the sound suppressor embodiment of another kind of form, make cylindric and axially aligning by the fluidic rolls of sheets with the passive sound suppressor of a drum type brake, form the complex muffler of the efficient attenuate acoustic noise of a kind of energy.In another embodiment, fluidic element structure body is plane or cylindric form, and the passive type element is wherein arranged, and in this form, the effect of passive type element is the sound stability that improves structure, and improves the frequency range that it can be decayed.
Fluidic oise damping means of the present invention can be made different thickness, and wherein the structure of thinner thickness is better.In " wallpaper " embodiment, the thickness of structure is normally in the scope of 1.0mm to 5.0mm, and a kind of like this structure can the sound wave of attenuation frequency ranges in 0 to 400Hz scope.Though all wish to reduce the thickness and the size of fluidic in great majority are used, prior art can only be with " wallpaper " thickness limits in the scope of 1.0～5.0mm.If can do fluidic thinner, littler, then structure can be decayed for the sound wave of 0～2000Hz frequency range.
Below in conjunction with specifying that accompanying drawing is done, can make the above-mentioned parties concerned of this invention and other advantage be able to clearer understanding and understanding.
Fig. 1 is the synoptic diagram of fluid amplifier;
Fig. 2 has showed fluid amplifier that has two control mouths in the jet loop;
Fig. 3 is according to the present invention, and the synoptic diagram of the embodiment of a thin slice fluidic of looking from the place ahead is shown in the figure many fluidics that cut out on thin slice (repeating individual);
Fig. 4 is the exploded view synoptic diagram of an embodiment, and this embodiment has the sheet group that has according to after the simplification of fluidic of the present invention and transport element;
Fig. 5 shows three fluidics of the present invention of series arrangement in a jet loop;
Fig. 6 is the skeleton view according to the embodiment of a cylindrical shape sound suppressor of the present invention, at this sound suppressor middle part a cylindrical shape fluidic architecture body is arranged;
Fig. 7 is according to the present invention, uses the model synoptic diagram of the pressure amplifier stage of EASY5 module foundation;
Fig. 8 is according to the present invention, the synoptic diagram of the embodiment of the final stage fluid amplifier that use EASY5 module is set up;
Fig. 9 A is according to the present invention, the schematic illustration of the embodiment of the trim plate fluidic architecture body that use EASY5 module is set up;
Fig. 9 B and 9C are the open-loop gain of Fig. 9 A institute representation model and the graph of a relation of phase place and frequency;
Fig. 9 D is the closed loop gain-frequency relation figure of Fig. 9 A institute representation model;
Figure 10 is the synoptic diagram that increases the embodiment of loop according to gain of the present invention;
Figure 11 A is according to the present invention, uses the EASY5 module and has the synoptic diagram of the embodiment of the pressure amplifier stage that feeds back supercharging;
Figure 11 B is the Performance Characteristics synoptic diagram about model among Figure 11 A;
Figure 12 A is the synoptic diagram according to the embodiment of a kind of active air conditioner noise elimination lining of the present invention;
Figure 12 B is the synoptic diagram about the Performance Characteristics of Figure 12 A sound suppressor.
But the invention provides the structure of ACTIVE CONTROL acoustic impedance, this structure is by many laminated foils of using The sheet group that forms forms with array format. Preferably each thin slice in the array includes fluidic Or the transport element between fluidic. Some are arranged in the fluidic is fluid amplifiers, these amplifications Device is preferably contacted. The input of series connection amplifier can be from towards a side of noise circumstance and be subjected to sound wave Excite, or towards the object that sends sound wave one side of needs control. This structure also be received in simultaneously into The fluid a certain amount of to produce " noise elimination sound wave " that mouth is modulated or the sound different with controlled sound wave phase place Ripple. Its effect is that the ACTIVE CONTROL acoustic impedance is cancelled sound wave, and what perhaps reduce to be covered by structure shakes The sound width of cloth that kinetoplast (such as the aircraft machinery space bulkhead) sends is penetrated.
A unique distinction of the present invention is to eliminate noise with jet as media, can use thus Offset from being exposed to the lip-deep " Mike of noise as " loudspeaker " on the whole surface of wall or other object Wind " input noise and vibration.
The definition of following relevant noun is not will negate the common implications of these nouns in this area, and Be to clarify in order to be more readily understood this invention. In specification and claims, noun is " big Cause the plane " comprise having the very structure of larger radius of curvature, as have the aircraft sidewall of cylindrical shape fuselage The body of wall cover layer. Used noun " thin slice " refers to penetrate with being suitable for making in specification and claims The material of fluid element and transport element, the thin slice that manufactures such as organic polymer (plastics), metal film etc. In order to obtain minimum volume, best, should be as much as possible thin for the manufacture of the thin slice of structure of the present invention. Although according to the needs of special occasions, thin slice can be as thin as 0.05mm and upper thickness limit can further be carried Height, the but usually thickness of thin slice is 0.2～0.5mm, " fluidic " refer to thin slice cut out one Part with accurate shape, it has at least one import to accept going out of fluid and a discharge fluid Mouthful. The size of the fluidic that cuts out is difference with the concrete application of fluidic architecture, the size of typical element Scope is 5mm2To 50mm2 A large amount of elements that each thin slice cuts out in array have formed " wallpaper " The shape structure. " fluid amplifier " is a kind of fluidic for amplifying the fluid acoustic pressure that supplies. " conduction Element " also a kind of fluidic of broad sense, but usually do not play amplification, and generally be positioned at one On the thin slice between one and second thin slice, to control fluid from fluidic on first thin slice to second thin slice The transmission of upper fluidic. Noun " sheet group " about fluidic refers to one group of thin slice that fluidic is arranged, Change successively on adjacent elements, usually also be inserted with transport element with the control flow at interlayer. Noun " sheet group pattern " or " the sheet group pattern of fluidic " refers to that a string joint group is woven in together and carries out fluid and passes The sheet group of the flow element of passing. According to the present invention, the sheet group consists of a fluidic architecture body to subtract usually Make an uproar. Generally, a fluidic array comprises some groups, and each sheet group comprises one at least, A plurality of fluid amplifiers preferably, " blow vent " refers to a zone of element on the thin slice, for example jet is put A part on the big device main body, this place's pressure and environmental pressure peer. " panel " refers to jet array The top layer thin slice, " microphone " (or claim input port or control mouthful) and " loudspeaker " (or claiming delivery outlet) position Thereon. " backboard " refers to the bottom sheet of jet array, and evacuation port (or claiming drain hole) is located thereon.
One of purpose of the present invention is to produce a desirable acoustic impedance, for indoor wall wave absorption device, desirable impedance should be that (wherein ρ is atmospheric density in the resistance impedance of scope between 1 ρ c to 2 ρ c, c is SVEL), for silencer, acoustic impedance be on some frequency ranges with the (impedance that 1.8～1.5j) ω are directly proportional, in order to can effectively suppress minimum evanescent mode, (j=in the formula
, ω=frequency loop). For the wall of a vibration, best impedance is zero, so that energy Suppressing the sound wave width of cloth fully penetrates. Ideal situation is to produce a scope in the frequency range that has much noise Impedance between 0.5 ρ c to 1 ρ c, or produce one in discrete a certain frequency or a plurality of frequency The very little impedance of individual 0.1 ρ c level.
As reference, can understand better relevant basic conception with an object lesson. With one by jet The wall lining that forms with transport element is example, and fluidic is arranged so that first the amplifying stage (" wheat The gram wind ") the control mouth and the delivery outlet of final stage amplifying stage (loudspeaker) all be exposed to incident acoustic wave, wherein, Make the normal pressure at control mouthful place produce a negative pressure (or title " noise elimination sound wave ") at equipped at outlet port, to support Incidence wave disappears. Because the reaction of delivery outlet has a time delay, so only working as frequency, the noise elimination sound wave is lower than In time, could in time arrive to limit frequency (below explanation), and frequency is higher than when limiting frequency, in the loop Damping must be enough greatly to prevent self-oscillation. Limit frequency f by passing through the jet loop (namely by control Mouthful to delivery outlet) accumulation time delay and determine. On this frequency, time delay d and one are approximately 60 °～90 ° phase shift is corresponding, and namely π/3＜fd＜pi/2 on the frequency that makes fd=π, comprises The gain of the whole loop of microphone and loudspeaker blow vent must be less than 1.0 to avoid generation from exciting Swing. This requirement realizes that by insert acoustic filter in loop the form of acoustic filter is damping hole Or capillary, and cavity etc. These wave filters have further reduced the upper frequency section that loop works.
With reference to the accompanying drawing that is used to illustrate certain embodiments of the invention, can understand this invention better.Should be understood that, the present invention have more than be limited to for embodiment, but comprised whole technology of and statement open, and those skilled in the art all changes and the correction after the content that reading is disclosed, done at this.
Fig. 1 is the synoptic diagram of fluid amplifier 10 1 examples, should be understood that, other design also is useful beyond this example.Shown in amplifier in, have a supply opening to be used for bringing fluid into amplifier body 14 through venturi 11 at the one end.Amplifier body is separated to two sides of the main body other end that has outlet 16a and 16b from the end of venturi 11.Delivery outlet 16a and 16b by a V-arrangement splitter plate on the output terminal that is positioned at amplifier body 14 15 separately, splitter plate have a reverse V-shaped cusp and with the center line L conllinear (this moment, center line L also was the line of symmetry of amplifier 10) of supply opening 12.Like this, fluid enters from supply opening 12, along the venturi 11 of the rectilinear flow shown in the arrow in amplifier body, is divided into two by the V-type splitter plate then, enters delivery outlet 16a and 16b respectively.For the hydrodynamic pressure that is controlled between delivery outlet 16a and the 16b distributes, amplifier shown in the figure also has the control mouth 18a and the 18b of pair of opposing, with in injection channel 15, flow to delivery outlet 16a from amplifier body 14 supply openings 12, the fluid flow direction of 16b is perpendicular.Like this, by changing the pressure of the control fluid that flows into control mouthful 18a and 18b, the fluid flow direction deflection of the amplifier body of flowing through enters the Fluid Volume of delivery outlet 16a and 16b with control.Because control mouthful 18a, 18b is pressure controlled in an acoustical signal, so delivery outlet 16a, 16b pressure can respond this pressure signal with a time delay and pressure gain.In addition, the amplifier 10 that is used as example shown in the figure has two couples of blow vent 17a that the position is relative, 17b and 19a, and 19b is positioned at two sides of amplifier body 14, and its pressure is roughly environmental pressure.
For simplifying analysis, set up mathematical relation here to the series connection fluid amplifier.And, for simplifying, also set up traditional illustration method to explanation about fluid amplifier.For example, Fig. 2 is the example according to a proportion expression fluid amplifier 20 in simplifying the jet loop of the present invention.The air that provides for fluid amplifier 20 enters from supply opening 22, and the fluid that the modulation of its sound wave is subjected to enter into fluid amplifier 20 opposite flanks by control mouthful 24a and 24b is controlled, and is exaggerated and anti-phase in the acoustic pressure of delivery outlet 26a and 26b output like this.If this amplifier is the chopped-off head of a polystage amplifier, then this amplifier links to each other with another amplifier stage by its delivery outlet 26a and 26b and subordinate is controlled a mouthful mode of joining.If this amplifier is last amplifier stage, then according to the present invention, controls the mouth pressure same-phase from the sound wave and the first order of delivery outlet output, and be drained, to prevent that control produces big influence to acoustic impedance for it in distance jet loop place enough far away.From the output of another delivery outlet, be output to the environment that needs noise reduction with the sound wave of First Control voice ripple out-phase and go.This delivery outlet is actually generation " noise elimination sound wave ", i.e. " loudspeaker " of out-phase sound wave.
The acoustic pressure that will be exaggerated has been added in the cavity 28 that is similar to the electric capacity effect, and cavity links to each other with a control mouthful 24a by damping hole 30.The effect of a low-pass filter 35 is played in the combination of cavity 28 and damping hole 30, promptly in low-frequency range, cavity 28 is filled and its pressure is reached control mouthful 24a, and at high band, before its pressure reaches control mouthful 24a, just emptying under pressure of cavity.In addition, blow vent 36 is shown a broken circle in the drawings, is led in the environment by passage 32 and damping hole 34.Aperture 34 has enough big damping can prevent that basically acoustic pressure from reaching blow vent 36.
Though Figure 1 shows that the single fluidic that cuts out from thin slice, from a thin slice, can cut out a lot of similarly fluidics usually.As shown in Figure 3, cut out a lot of fluidics 10 on thin slice 100, fluidic is a fluid amplifier herein.As noted above such, the single size of formula fluidic that cuts out is approximately from 5mm
2To 50mm
2Therefore, a fluidic architecture body " wallpaper " that is used to reduce or controls noise in the aircraft cabin will comprise and have thousands of the sheet groups that cut out the formula fluidic.The supply line (not shown) that links to each other with the supply opening that cuts out the formula fluidic is housed, so that the required fluid of feed streams structure work also is equipped with the required pipeline of fluid that collection is discharged from evacuation port on backboard on the backboard of fluidic architecture body.
Fig. 4 is the decomposing schematic representation according to a sheet group 50 of the present invention, and this sheet group is made up of a plurality of organizing together with the thin slice of the band fluidic that constitutes the controlled structure of impedance.Usually, organize the array that constitutes stacked together by laminar a plurality of of fluidic, to form an available fluidic architecture body.Although with reference to Fig. 3, as discussed above, in actual applications, contain on each thin slice and manyly cut out the formula fluidic, but for simplicity, each plane lamina 40 of sheet group 50,41,42,43,44,45 and 46, all have one respectively and cut out formula fluidic 40a, 41a, 42a, 43a, 44a, 45a and 46a.For simplicity, owing to only have a fluidic on each thin slice, every thin slice among Fig. 4 is regarded one " fluidic ".Comprise a supply opening 40b on first element 40 that is positioned at sheet group 50, first element 40 promptly said " backboard " by 40～46 formed of plane jet elements group 50.For example, when the planar chip group of element is used as aircraft cabin sound wave wallpaper a part of, the air feed of port 40b can be from the air-conditioning system of aircraft, also available in addition another kind is source of supply easily, the fluid that supplies flow into the supply opening 40b of fluidic 40, enter the supply opening of fluidic 41 then and be divided into two strands to delivery outlet 41c and 41d.The ratio that fluid is assigned to delivery outlet 41c and 41d depends on the pressure at the control mouth 41e place of amplifier 41a.Control mouthful 41e links to each other with " microphone " port m on the panel 46 of jet sheet group with 42 by fluidic 45,44,43.Two delivery outlet 41c on the element 41 and 41d link to each other with the 43d fluid by the control mouth 43c of the next amplifier stage 43a on conduction thin slice 42 (promptly by the 42c and 42d of entering the mouth) and the thin slice 43.Note fluid amplifier 43 through inlet 42bb, 41bb, 40bb provides fluid by inlet 43bb, more than each inlet join with same fluid supply inlet 40b successively again.
The delivery outlet 43e of amplifier stage 43a and 43f link to each other by transport element 44 (being port 44e and 44f) fluid with 45f with the control mouth 45e of last amplifier stage successively.The road output 45g (i.e. " loudspeaker ") of output amplifier 45a is by osculum p and environmental communication on the panel 46, and export successively through small holes 44j on another road, 43j, and 42j and 41j are emptied to the evacuation port that is positioned on the back element 40.Should be realized that, in exporting environment to before, the continuous amplification of a plurality of fluid amplifiers is all passed through in the output of any group.The acoustic pressure and the incident acoustic wave through amplification and phase inversion (or claiming out-phase) of the output of delivery outlet 45g place meet, shown in label 55, and incident acoustic wave decayed, it should be noted that the pressure at " microphone " port m place is incident sound pressure by from the residual pressure behind the output offset of " loudspeaker " port.
Generally speaking, the effect of initial several amplifier stages is to amplify pressure, and the effect of last amplifier stage is to improve fluid flow.For reaching this purpose, last amplifier stage is composed in parallel by one or more amplifiers, and the target of last amplifier stage is that the volumetric velocity with incident acoustic wave is complementary.
For understanding the design's requirement better, provide an example below: suppose sound wave vertical incidence that an amplitude is 85dB to the fluidic architecture body, the peak particle velocity of sound wave is 0.0027 meter per second.Further hypothesis just became 0.009m/s for ± 30% so should stablize flow velocity through its sound wave pulsation after the steady flow rate modulation of last amplifier stage.If repetitive sheet group area is 0.0001 square metre, and two in parallel uses of amplifier, then any the volumetric flow rate by the most last two amplifiers is 9 * 10
-7m
3/ s.
For making last amplifier stage produce the fluid of this quantity, the preorder amplifier must amplify surplus pressure with 10～1000 amplification factor.Usually, the span of the factor is about 50 to 500.According to the LOCAL FEEDBACK situation of amplifier, each amplifier stage improves acoustic pressure with 4 to 25 amplification factor, will discuss to this below.The thickness of fluidic changes in 5mm at 1mm usually, also uses other thickness in application-specific.Constitute the thin slice change between 10 to 50 usually of structure, single group of structure is an approximate square region, and the length of side is from 3mm to 100mm, or more generally situation promptly from the scope of 5mm to 50mm, the length of side in single zone is more little, and the high frequency limit of structure performance is big more.Structure with such parameter can attenuation frequency ranges be the sound wave of 0.1Hz to about 2000Hz, and the most common situation is from this scope of 1Hz to 400Hz.
Fig. 5 is the synoptic diagram that a plurality of the sort of fluidics as shown in Figure 2 are cascaded.As shown in the figure, fluidic 20x, 20y and 20z respectively have a fluid supply opening 22, two control mouthful and two delivery outlets.According to figure from left to right, the output 20b of the first amplifier 20x and 20c are amplified by the second amplifier 20y, and its output 20d and 20e are then amplified by the 3rd amplifier 20z again.Obviously, according to can also connect more amplifier more than three of specific needs.As previously mentioned, the output 26a that has amplified through sound (or claim " loudspeaker ") exports the external environment condition that needs noise abatement to from the 3rd (afterbody) amplifier, for example in the aircraft cabin.Environment also links to each other with the control mouthful (microphone opening that is equal to Fig. 4) of amplifier stage 20x simultaneously.Another road output 26b is introduced to the place beyond amplifier output and the environmental interaction zone, and preferably is emptied to this zone of action and the place of certain distance is arranged so that for the interference minimum from the output at 26a place.As the technician who is fluid amplifier loop design field was known, resistive and capacitive element (as shown in the reference numeral 28) need be added on each aspect in the loop and make all amplifier stages be operated in the required pressure differential in the range of linearity so that obtain.
Fig. 6 is the synoptic diagram according to another noise attentuation structure embodiment of the present invention.This structure is a sound suppressor 75, and wherein jet sheet group pattern is cylindrical shape rather than flat shape roughly.As shown, structure comprises a tubular body 70, and this tubular body position is in the middle surrounded by the fluidic lamella array 72 that twines along cylindrical direction, as previously mentioned, fluidic comprises the amplifier of series connection, for use in pipe 70 inside the acoustic pressure on structure surface being amplified.Fluid through pressurization is supplied to structure by pipe 74, and institute's fluid that supplies undertaken tone system by the interior pressure of pipe 70, and the noise elimination sound wave that obtains enters pipe 70 to carry out acoustic attenuation.Be emptied to pipe 76 from the unwanted sound wave of output amplifier delivery outlet output, its direct sound waves and stable fluid flow back in the pipe core 70 together, pipe 74 can join with pipe 70 upstream end or dirty place (being represented by dotted lines) of jet array, as shown in Figure 6.Another kind of situation is that unwanted sound wave is emptied at a distance from pipe 78.
This jet array can bend to cylindrical shape by planar array to be formed, or is made up of the sheet group that the continuous fluidic thin slice that twines round pipe core 70 constitutes.The fluidic sheet group pattern of columnar or general plane shape can be with the wave absorption element of pure passive type as replenishing realizing the stability of active jet loop, and depend merely on the frequency range that jet array self-acting has increased decay.An example of relevant this design will provide in the following discussion.
The invention allows in environment the decay sound wave method, prevent the vibrating object environment width of cloth method of penetrating sound wave towards periphery, subdue in noise circumstance because the method for the caused object vibration of sound wave and absorb the method that will incide the sound wave on the object.A kind of sound wave method that absorbs in back comprises between the object that fluidic architecture body of the present invention is inserted into sound wave and needs protection to avoid the sound wave influence.Deliver to the supply opening of fluidic architecture body continuously through the fluid of pressurization, simultaneously, acoustic pressure that will absorbed sound wave at the place, input port of structure by continuous probe.The acoustic pressure that is detected is modulated continuously to produce and the different sound wave of sound wave phase place that is detected, the sound wave of promptly eliminating the noise.The fluidic architecture body needs protection in environment continuously and has the capacity fluid of noise elimination sound wave with output around the object of avoiding the sound wave influence, so that subdue the acoustic pressure in the environment basically, and has therefore subdued the pressure that these sound waves cause object.
In order to subdue the acoustic emanation that derives from vibrating object, adopted process similar to the above, difference be the continuous noise elimination sound wave according to fluidic architecture body of the present invention output be positioned at vibrating object around and the sound wave width of cloth of having eliminated vibrating object basically penetrate.Like this, noise just roughly has been eliminated from the propagation of vibrating object to its place environment.Similarly, by the elimination of the caused object vibration of sound wave can the application of the invention the fluidic architecture body export capacity from its delivery outlet continuously to the adjacent domain of the body surface that is exposed to noise circumstance and realize through the method for the fluid that amplifies.This to acting on subduing of sound wave on the object in the environment, significantly reduced the vibrational excitation of the object that sound wave causes.
Like this, the present invention not only provides the fluidic architecture body with very wide geometric configuration scope that is suitable for various application-specific, the method for subduing the object vibration that causes because of sound wave also is provided simultaneously, has subdued object and send the method that the sound wave width of cloth penetrates and be used for the method for absorption in the sound wave of object to environment.Moreover, the present invention also provides the structure with ability that the wide sound wave wave band from 0 to about 2000Hz very wide frequency ranges is controlled first.Control for broadband sound like this or noise, it has been generally acknowledged that using electronics microphone and speaker system is impossible realize, because this needs thousands of this kind devices.
Stated as mentioned above and below, following Example is illustrated is specific embodiment of the present invention.These example purposes are explanation and make the present invention be convenient to understand, and are not construed as limiting the invention.
Can carry out modeling to the discrete component in the fluid amplifier loop by one group of standard component with EASY5 (engineering analysis system 5) software and usefulness, this software is provided by the Boeing that is positioned at the Seattle, Washington.The simulation of using this software to carry out has produced following observations and result, and these observationses and result provide some the useful guidances to the low impedance structure body design that is used for certain applications according to the present invention.But should be understood that the present invention is not limited to the content of following simulative example, this example has illustrated the conventional transfer function analysis of open loop (about stability) and closed loop (relevant performance).
First is applied as a trim plate with low radiation rate, as employed in jet plane.The impedance of this trim plate is designed to propagate the dielectric property impedance ρ c that the width of cloth penetrates identical or littler.If the impedance of trim plate is 1 ρ c, then to hang down 6 to 10 decibels along the trim plate that the normal direction of trim plate is penetrated with the mode width of cloth of plane wave or the noise ratio that the difference of penetrating these two kinds of situations from all directions width of cloth in a scattering region from the trim plate is sent by the trim plate the vibration not have to vibrate by sound wave.
Second application is a catheter type sound suppressor, such as the exhaust apparatus of reserve power unit, or the air conditioner conduit.Generally speaking, in jet plane, the noise from air conditioner of low frequency result to from the compression of engine outside the reinforcement eddy current air mixed and repetitive cycling in the cabin of air.Though damping capacity can't directly calculate by EASY5 software, the impedance of exporting from this program can be used to by existing conduit one acoustics program estimated performance.
Selected basic amplifier model as shown in Figure 7, though also can select other model in some applications for use.Here selected a summing amplifier 85 so that make an additional feedback loop in this amplifier stage go to improve gain, as described below such.Amplify through the pressure of gain 84a and 84b and to be assumed to be respectively from the factor 3 of the first control mouthful 80a with from the factor 4 of the second control mouthful 84b.Corresponding time delay 86a and 86b hypothesis are respectively 0.07 and 0.06 millisecond, and time delay model approaches with the Pade on one 8 rank, promptly have the polynomial ratio in two 8 rank in the s plane of unit amplitude.This just provide the good linear of phase place to approach on the interested whole frequency range (0 to 1000Hz), output after totalizer 88 places addition by delivery outlet 89 outputs.
Also have input and output impedance and little cavity in each port, introduce the phase lag problem that needs consideration.They are modeled as the low-pass first order filter that has unity gain and variable time constant at passband, and a plurality of wave filters are combined into a wave filter at the control mouth.Because cavity and impedance have determined the time constant of a minimum, so if wish to carry out filtering for increasing loop stability, then will select a bigger time constant, this can increase resistance and realize by further dwindling aperture or increasing cavity.
As shown in Figure 8, above interconnective loop element, a terminal amplifier of representing with symbol 95 modelings of EASY5 is arranged.Because little output load impedance, the pressure amplification factor is no longer suitable here.As being seen in the drawings,, at this moment selected to have the amplifier of pair of control mouth because pressure feedback is no longer feasible.Through input filter 92 filtering, amplify at 94 places in gain from the signal of controlling mouth 90, and carry out time delay at delayer 96 places, forms at delivery outlet 98 and export.
Fig. 9 A is depicted as a continuous Pyatyi system, and this loop is applicable to the analysis to interior of aircraft trimming system performance.By the sound space on trim plate surface, mixed mutually from the noise elimination sound waves of loop noise elimination sound wave delivery outlet output at microphone opening 102 with process feedback 110 from the sound wave in initial source 100.Residual noise enters 4 grades of acoustic pressure amplifiers 104 (shown in Figure 7 is the sort of), enters environment by flow amplifier stage 106 (shown in Figure 8 is the sort of) then.Environment is penetrated impedance 108 expressions with the width of cloth, and resistance value is assumed to be 1 ρ c.Suppose that the output load impedance at amplifier 106 places can ignore, because the distance from speaker port to microphone opening is assumed to be 0.01 meter, so have a delay from the signal of this delivery outlet output.The measurement of open-loop gain is the top input 109 that exports same summation contact to from summation contact 102; And the measurement of closed-loop characteristic is to export 103 from the left end input 101 of summation contact to it.
Fig. 9 B is depicted as open-loop gain, and component parameters is through adjusting so that phase place is 180 ° of gain margins of locating 10dB in loop.Phase margin is 90 ° when gaining on the nullring road, and Fig. 9 C is depicted as the corresponding closed-loop performance, for obtaining this performance, component parameters is done following hypothesis, concerning making up each the pressure amplifier stage in 104, has amplification factor 4, time delay 0.07ms, and 10, the low pass angular frequency of 000Hz.Flow amplifier stage 106 shown in Fig. 9 A supposes to have 3.2 * 10
-8m
3/ SNm
2Transmission admittance, 0.07 millisecond time delay and the low pass angular frequency of 80Hz.In some cases, can obtain more performance at attenuation band, but the outer amplification of attenuation band can strengthen also with less allowance.
A kind of method that reduces fluid amplifier element number in sheet group loop will be described below.A kind of like this design can obtain thinner sheet group, thereby has reduced volume, weight and the cost of structure.Increase a regenerative feedback loop on each amplifier, need only gain around feedback less than 1, amplifier gain will stably improve.In Figure 10, when not with impedance Z
1116 and Z
2118 when linking to each other, amplifier 112 have one from input port 111a to delivery outlet 114 gain F
1, and one from input port 111b to delivery outlet 114 gain F
2With Z
1And Z
2(common Z
1, Z
2Be damping hole) when linking to each other, a part of pressure P at delivery outlet 114 places
2111b is detected in the input port, and this partial pressure is β=Z
1/ (Z
1+ Z
2).Pressure value P at output 114 places
2P for the 111a place, input port of amplifier
1Through gain F
1The feedback pressure of the input port 111b of pressure after the amplification and amplifier is through gain F
2Amplify back gained pressure sum.Therefore, P
2=F
1P
1+ β F
2P
2Or P
2=(F
1/ (1-β F
2)) P
1Do not having under the feedback, the pass is P
2=F
1P
1Amplifier arrangement as shown in figure 10, it is 1/ (1-β F that gain increases the factor
2).Calculating Z
1And Z
2The time, must take into account with the time delay relevant and with the related capacitive of cavity of feedback control loop with propagation distance, but as long as β F
2Be not equal to 1, loop is exactly stable.
In the feedback model that EASY5 built, as shown in figure 10, suppose that feedback has been added to the second control mouthful 80b that has less gain 3 among Fig. 7, Z
1Be the input impedance of the second control mouth, and Z
2It is a suitable small damping.
Will be appreciated that pair amplifier input in addition suitably filtering can change the performance of jet loop.If replace low-pass filter with bandpass filter, the frequency range with frequency of desired properties can upwards improve, and its cost is that low frequency performance descends.About using resistance element and capacitive element to realize the method for above-mentioned wave filter, be conspicuous to technician in the sound filtration art.
Figure 11 A is the synoptic diagram of the pressure amplifier stage of a band feedback supercharging.In essence, Figure 11 A is the combination of loop described in loop shown in Fig. 7 and Figure 10, and has a time delay in backfeed loop.The benefit of this system is to make structure become thinner because in the sheet group less fluidic is arranged, and its cost is the high frequency performance that has reduced loop.
Figure 11 B is the output curve diagram of loop shown in Figure 11 A.Figure 11 B has clearly illustrated the situation big (20dB) that the ratio of gains from the first control mouth 140 to delivery outlet 142 is fed back through the nothing of the second control mouth 144, and under latter event, the factor of gain block 146 is 4 (12dB).Because the time delay in the loop, it gains, and raising is the highest can only to be used in the hundreds of hertz.
Figure 12 A is depicted as a sound suppressor lining rough schematic view.This lining is made up of active lining element 120 and passive type lining element 122, and its corresponding acoustical behavior has been shown among Figure 12 B.Passive lining 122 has dual function.At first, it provides damping for the feedback from the microphone opening of active lining to its speaker port, and secondly, it provides the function that the above frequency band of active lining decay wave band is decayed.
Active lining element 120 shown in Figure 12 A has occupied 1/2 and the noise sound wave 128 in the face of needing to control on whole linings surface.Active lining element 120 is made up of the sheet group that roughly forms by the fluidic of configuration shown in Figure 9, and different is only to have used two pressure amplifier stages.Each amplifier stage has the structure shown in Figure 11 A.In addition, be stamped the impedance layer that an impedance is 4 ρ c on the panel 125 of sheet group, be to be understood that this resistance is the mean value on whole group zone, that is, if speaker port occupies 5% of whole group zone, then the resistance before the loudspeaker is 5% of 4 ρ c.
The passive type part 122 of lining is that the resistance superficial layer 126 of 1 ρ c is formed by impedance, is positioned on the array of depressions that depth d is about 1 inch, and array of depressions separates suppressor case 130 and active and passive type element.It should be noted that depression has occupied the space of basic unit 126 belows of impedance 1 ρ c, and the degree of depth is assumed to be the space below 0.25 foot the active lining element 120.
Performance diagram 12B provides the estimation by the attenuation of the lining of the unit length that disposes shown in Figure 12 A.This unit length equals the diameter of air conditioner sound suppressor conduit, supposes that it is 11 inches xsect that this sound suppressor has interior diameter.
Though carried out graphic to the preferred embodiments of the present invention and explanation, should be appreciated that the various modifications of being made thus all do not exceed the essence and the scope of the invention described above and back claim.
Claims (20)
1. the method for sound wave in the environment of decaying, this method comprises:
(a) supply opening to the fluidic array provides the fluid that passes through pressurization, and this fluidic array has a panel towards the residing environment of sound wave that will be attenuated, and has mutual fluid transmission at least in a part of fluidic;
(b) when fluid is flowed through fluidic, the confession fluid carry out tone system, and
(c) fluid through tone system by the delivery outlet on arraying bread board output capacity is to subdue the acoustic pressure on the arraying bread board basically.
2. by the method described in the claim 1, it is characterized in that the modulation of carrying out in the described step (b) is included in the amplification of being carried out in the fluid amplifier of a plurality of series connection.
3. by the method described in the claim 1, it is characterized in that the output of carrying out in the described step (c) comprises in order to attenuation frequency ranges from 0～2, the output that the sound wave of 000Hz is required.
4. by the method described in the claim 1, further comprise detection to the sound wave that will be attenuated, and wherein the modulation of being carried out in step (b) comprises: is that 4～25 the factor is amplified by the fluid amplifier be made up of fluidic with size, to produce and the different sound wave of sound wave phase place that detects.
5. by the method described in the claim 1, also comprise from the sound wave that will be attenuated and import acoustic pressure, and use this input acoustic pressure to influence the modulation step that is used to export and import the different sound wave of sound wave phase place to the fluidic array.
A noise that is used for controling environment, have the structure of controlled acoustic impedance, this structure comprises:
(a) a fluidic array has at least a part of fluidic to comprise fluid amplifier, and this array has a panel and a backboard;
(b) at least one fluid supply opening, the fluid of on backboard, supplying with reception;
(c) at least one input port is used to survey the acoustic pressure of controlled sound place environment on panel; And
(d) the contiguous delivery outlet at least one and input port is on panel, is used for fluid to the environment output capacity at controlled sound wave place to offset the sound wave of environment.
7. by the structure described in the claim 6, it is characterized in that described fluidic array comprises that one is the array of flat shape substantially.
8. by the structure described in the claim 6, it is characterized in that described fluidic array comprises that one is roughly the array of drum.
9. by the structure described in the claim 7, it is characterized in that the described fluidic of at least a portion comprises the fluid amplifier that having is together in series carries out the fluid transmission.
10. by the structure described in the claim 8, it is characterized in that the described fluidic of at least a portion comprises the fluid amplifier that having is together in series carries out the fluid transmission.
11. the structure by described in the claim 6 further comprises: at least one evacuation port, extend to the panel zone enough far away of a distance arrays from the backboard of array, interfere with the sound wave of exporting from delivery outlet avoiding basically.
12. the structure by described in the claim 6 is characterized in that, described each fluidic comprises a thickness approximately from the thin slice of 0.1mm to 1.0mm.
13. the structure by described in the claim 6 is characterized in that described fluidic compiles the thickness of the array that forms approximately from 1mm to 25mm.
14., it is characterized in that the described array that is roughly the plane has comprised the inwall of aircraft cabin by the described structure of claim 7.
15. by the described structure of claim 14, wherein at least one delivery outlet is towards the inside in cabin, simultaneously the evacuation port of array extend to behind the bulkhead the zone and away from bulkhead.
16. the structure by described in the claim 14 wherein has the outer wall of a delivery outlet towards the cabin at least.
17. by the structure described in the claim 6, fluidic array wherein comprises and is used for the series connection fluid amplifier that controlled fluid transmits, so that the output of generation after sound amplifies is in order to the noise of vertical incidence on the decay jet plane cabin.
18. one kind is absorbed into the method that is mapped to the sound wave on the object, this method comprises:
(a) assign a fluidic architecture body between with absorbed sound wave and object, this structure comprises the array that is made of the fluidic that the fluid transmission is arranged each other;
(b) fluid after the supply opening of fluidic architecture body provides pressurization;
(c) survey in the absorbed acoustic pressure in the input port of structure;
(d) when the confession fluid is flowed through fluidic, the pressure of the fluid supplied is modulated to produce and the different sound wave of sound wave phase place that is detected according to the acoustic pressure that detects; And
(e) export capacity around the object, have the modulation fluid with the different pressure surge of incident acoustic wave phase place, eliminating the incident acoustic wave pressure that acts on the object basically.
19. an elimination is by the vibrating object method of the sound wave penetrated of the environment width of cloth towards periphery, this method comprises:
(a) add a fluidic architecture body between vibrating mass and environment, this structure comprises the fluidic array that has controlled fluid to transmit each other;
(b) supply opening to the fluidic architecture body provides the fluid that passes through pressurization;
(c) width of cloth that absorbed of the detecting structure body input port acoustic pressure of penetrating sound wave;
(d) when the confession fluid is flowed through the fluidic architecture body, the pressure of confession fluid is modulated, to produce and the different sound wave of sound wave phase place that detects according to the acoustic pressure that is detected;
(e) near the modulation fluid with the different pressure surge of incident acoustic wave phase place of having of the delivery outlet of the fluidic architecture body environment output capacity vibrating object, the sound wave width of cloth of environment is penetrated to eliminate vibrating mass basically.
20. an elimination is in the method that the object in the noise circumstance causes vibrating because of noise, this method comprises:
(a) at object and contain between the noise circumstance of the sound wave that can cause vibration and add a fluidic architecture body, this structure comprises the array that the fluidic that has controlled fluid transmission is each other formed;
(b) supply opening to the fluidic architecture body provides the fluid that passes through pressurization;
(c) detection is in the acoustic pressure of the sound wave of structure input port absorption;
(d) when fluid is flowed through the fluidic architecture body, according to the acoustic pressure of being surveyed the pressure of supplied fluid is modulated to produce and the different sound wave of sound wave phase place that is detected;
(e) from noise circumstance the adjacent structure delivery outlet of object surfaces output capacity have a modulation fluid with the different pressure surge of detected acoustic pressure phase place, thereby eliminate the vibration of object basically.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB971184674A CN1192352C (en) | 1996-09-17 | 1997-09-16 | Fluidic element structure body for controlling noise and vibration, and control method thereof |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US710352 | 1985-03-11 | ||
| US08/710,352 US6009180A (en) | 1996-09-17 | 1996-09-17 | Fluidic element noise and vibration control constructs and methods |
| CNB971184674A CN1192352C (en) | 1996-09-17 | 1997-09-16 | Fluidic element structure body for controlling noise and vibration, and control method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1177792A true CN1177792A (en) | 1998-04-01 |
| CN1192352C CN1192352C (en) | 2005-03-09 |
Family
ID=34634858
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB971184674A Expired - Lifetime CN1192352C (en) | 1996-09-17 | 1997-09-16 | Fluidic element structure body for controlling noise and vibration, and control method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1192352C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105118493A (en) * | 2015-07-29 | 2015-12-02 | 陕西师范大学 | Longitudinal vibration converter achieving one-end inputs and multi-end outputs |
| CN105944212A (en) * | 2016-05-18 | 2016-09-21 | 湖南明康中锦医疗科技发展有限公司 | Noise-reducing mask of respirator and respirator provided with noise-reducing mask |
-
1997
- 1997-09-16 CN CNB971184674A patent/CN1192352C/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105118493A (en) * | 2015-07-29 | 2015-12-02 | 陕西师范大学 | Longitudinal vibration converter achieving one-end inputs and multi-end outputs |
| CN105118493B (en) * | 2015-07-29 | 2018-12-04 | 陕西师范大学 | The compressional vibration converter of one end input multiterminal output can be achieved |
| CN105944212A (en) * | 2016-05-18 | 2016-09-21 | 湖南明康中锦医疗科技发展有限公司 | Noise-reducing mask of respirator and respirator provided with noise-reducing mask |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1192352C (en) | 2005-03-09 |
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