CN2526750Y - Assembly for reducing resonance frequency of thermoacoustic system - Google Patents

Abstract

The utility model relates to an assembly for reducing resonance frequency of thermoacoustic system, which includes a piece of solid mass block and at least one metal membrane box; wherein, the end surface of the solid mass block is connected with one end of the metal membrane box. The assembly is arranged at any part of a resonatron of the thermoacoustic system and two ends of the resonatron of the thermoacoustic system are closed. The utility model can remarkably reduce the natural frequency of the thermoacoustic system without increasing the dimension of device, thereby solving the problem caused by overlarge dimension of the existing thermoacoustic system. The utility model remarkably reduces the natural frequency of the thermoacoustic system. While the exchange efficiency of the existing thermoacoustic system can be effectively improved after the thermoacoustic frequency is reduced. The utility model can increase the selecting freeness on working substances.

Description

Be used to reduce the assembly of thermoacoustic system resonant frequency

Technical field

The utility model relates to a kind of parts that are used for thermoacoustic system, particularly relates to a kind of elastic diaphragm capsule-mass assembly that uses in the device of thermoacoustic system resonant frequency that reduces.

Background technology

The operating frequency of thermoacoustic system can not be excessive, because the thermoacoustic system conversion efficiency generally reduces along with the rising of frequency, this can be shown by following sound merit generation rate equation: ${\mathrm{\Σ}}_w^{\′}=\frac{1}{2}{T}_0{\mathrm{\β}}_0\mathrm{Re}\left[\tilde{U}{\tilde{p}}^{*}{f}_{\mathrm{WT}}\right]\frac{1}{T_0}\frac{d{T}_0}{\mathrm{dx}}-\frac{1}{2}\frac{(r-1)A_f\mathrm{\ω}}{{\mathrm{\ρ}}_0{a}_0^2}{\left|\tilde{p}\right|}^2{g}_{\mathrm{wk}}----\left(1\right)$ $-\frac{1}{2}\frac{{\mathrm{\ρ}}_0\mathrm{\ω}}{A_f}{\left|\tilde{U}\right|}^2{g}_{\mathrm{w\μ}}$ The physical significance of relevant symbol can list of references [1] in this formula (Xiao Jiahua. " theoretical research of the hot machine of thermoacoustic effect and back-heating type (comprising refrigeration machine) ", the 24th page, Beijing: Inst. of Physics, CAS, 1991) year is introduced: in the following formula, first of the right is illustrated in following theoretical maximum merit that can produce of certain thermograde, and second and the 3rd then represent owing to limited exchange capability of heat and sound power consumption that viscous drag caused are diffusing.This formula shows that the power consumption that the deficiency of exchange capability of heat and viscous drag cause is loose to be increased along with the increase of frequency, so, for a thermoacoustic system, if can reduce frequency, will reduce to dissipate, improve the conversion efficiency of thermoacoustic system.

Usually, the resonant frequency of a sound system (comprising thermoacoustic system) depends mainly on three factors: the length dimension of the geometry, particularly system of (1) system; (2) boundary condition of system; (3) velocity of sound of the used working media characteristic, particularly working media of system.

The acoustic construction of existing thermoacoustic system mainly contains: (1) standing wave type half-wavelength (or claiming 1/2nd wavelength) sound system; (2) standing wave type quarter-wave system; (3) has the quarter-wave system in partial row ripple loop.

The lowest resonance frequency of these sound systems is mainly determined by the velocity of sound of working gas, the length of pipe and the boundary condition of sound system.

Table 1 has provided above-mentioned three kinds of sound systems in the minimum natural reonant frequency data that adopt under gas with various medium and the different pipe ranges.As can be seen from Table 1, for the resonant frequency that makes sound system is lower than 50 hertz, then the length of pipeline generally will be at (to helium) more than 5 meters, otherwise resonant frequency will be far above 50 hertz.As seen, be lower than 50 hertz acoustic resonance system if make a frequency, its size is general huger so, not only increases the occupation of land space of system but also consume lot of materials, is unfavorable for practicability.Do not increasing under the size situation of system, can take to change the gas working medium kind, its velocity of sound is reduced, thereby reducing the resonant frequency of thermoacoustic system.But the working medium that is applicable to thermoacoustic system usually generally all adopts environmental protection, nontoxic and safe inert gas, as helium, neon, argon gas, nitrogen, carbon dioxide etc.The molecular weight of these gases is generally less, is difficult to reduce effectively the velocity of sound.Particularly, in the sound-driving low-temperature thermoacoustic refrigerator of heat, the general helium that adopt could obtain low temperature as working media more, but the velocity of sound of helium is very high, reaches about 1000 meter per seconds.As seen, these two kinds of methods are limited in the ability that reduces frequency, reduce aspect the system dimension.

The relation of the minimum intrinsic frequency of the different sound systems of table 1 and working gas, pipeline length

Annotate: (in the calculating of table 1, helium, neon, argon gas and the nitrogen velocity of sound when temperature T=300K is respectively 1019.4m/s, 353m/s, 455.9m/s, 322.4m/s.In addition, row ripple loop length is 0.2m in the travelling-wave type quarter-wave system)

Summary of the invention

The purpose of this utility model: be lower than 50 hertz acoustic resonance system in order to solve frequency of the existing making of above-mentioned prior art, its size is huger, not only increases the occupation of land space of system but also consume lot of materials, is unfavorable for the problem of practicability; It is generally less that next is to overcome the gas working medium kind molecular weight that is applicable to thermoacoustic system usually, is difficult to reduce effectively the problem of the velocity of sound; Thereby provide a kind of elastic diaphragm capsule-mass assembly that is used to reduce the thermoacoustic system resonant frequency.

The assembly that is used to reduce the thermoacoustic system resonant frequency that the utility model provides comprises: the metal bellows of at least one multilayer; It is characterized in that: also comprise a solid masses piece, the end face of this solid masses piece is connected with the metal bellows of a multilayer.

The both ends of the surface that also are included in the solid masses piece are fixed the metal bellows of a multilayer respectively.

The metal bellows of described multilayer such as wavy metal bellows.

During use the described assembly that is used for reducing the thermoacoustic system resonant frequency is installed in any part of the resonatron of thermoacoustic system, the other end and the resonatron of solid masses piece are fixed, the resonatron of the other end thermoacoustic system of the metal bellows of multilayer is fixed, the closed at both ends of the resonatron of this thermoacoustic system.

For make mass in sound system with gas motion, the assembly that the utility model provides is installed on any part in the resonatron of thermoacoustic system, the vibrational system of forming a quality-spring, wherein, gaseous mass in the system just is equivalent to the oscillating mass of this vibrational system, the compressibility of gas has then constituted the effective spring in this vibrational system, when the equivalent mass that can control this vibrational system and equivalent spring, so just might change the eigentone of this vibrational system, according to the General Principle of quality-spring vibration system, thereby effective oscillating mass of increase thermoacoustic system just can reduce the purpose that the intrinsic frequency of thermoacoustic system reaches the natural reonant frequency that reduces thermoacoustic system.

The utility model is as follows to the benefit that existing hot vocal cords come:

(1) needn't solve existing thermoacoustic system because of the oversize difficulty that produces by increasing the intrinsic frequency that device size just can reduce thermoacoustic system significantly;

(2) add the size that measure of the present utility model can greatly reduce existing thermoacoustic system, and reduce the intrinsic frequency of thermoacoustic system significantly; And hot acoustic frequency can improve the conversion efficiency that has thermoacoustic system now after reducing effectively.

(3) can increase the free degree that working medium is selected.For example, can mainly be conceived to the heat sound conversion performance of working medium and not necessarily pay close attention to the situation of its velocity of sound.

Description of drawings

Metal bellows spring-mass assembly assumption diagram of using in the device of Fig. 1 reduction thermoacoustic system of the present utility model resonant frequency.

Fig. 2 is the structural representation that has 1/2nd wavelength thermoacoustic systems of metal bellows spring-mass assembly.

The drawing explanation:

Folded-2 room temperature coolers-3 of high temperature heater (HTH)-1 heat plate

Resonatron-4 mass-5 metal bellows spring-6

Weld-7

The specific embodiment

Embodiment 1

Make (elastic diaphragm capsule-mass) assembly that is used to reduce the thermoacoustic system resonant frequency by Fig. 1, this assembly comprises: the wavy metal bellows 6 of a solid masses piece 5 that metallic copper material is made and a commercially available multilayer, and the end face of copper solid masses piece 5 welds (weld is 7 among the figure) mutually with the wavy metal bellows 6 of this multilayer.And the other end of the other end of the solid masses piece 5 of this assembly and wavy metal bellows 6 is separately fixed at any part in the resonatron 4 of thermoacoustic system, the closed at both ends of the resonatron 4 of thermoacoustic system.In the present embodiment, the diameter of resonatron 4 is 50 millimeters, a segment length L on the left side ₁=0.2 meter, one section L on the right ₂Length can change.Adopt the stainless steel wave bellows spring 6 of solder type, coefficient of elasticity is 2400N/m (Newton/meter), and the quality of the mass 5 that welds together with spring is 0.2kg (kilogram).

Embodiment 2

Make (elastic diaphragm capsule-mass) assembly that is used to reduce thermoacoustic system (1/2nd wavelength thermoacoustic systems) resonant frequency by Fig. 2.

This assembly has the wavy metal bellows 6 of a solid masses piece 5 that metallic copper material makes and a commercially available multilayer, and the end face of copper solid masses piece 5 welds (weld is 7 among the figure) mutually with the wavy metal bellows 6 of commercially available multilayer, the other end of the end face of copper solid masses piece 5 is at welding one wavy metal bellows 6, and the other end of the other end of solid masses piece 5 and wavy metal bellows 6 is installed in the resonatron closed at both ends of the resonatron of this thermoacoustic system.Thermoacoustic system is 1/2nd wavelength thermoacoustic systems in the present embodiment, and it mainly comprises common thermic sound converting unit, resonatron; Present embodiment as shown in Figure 2.Wherein, thermic sound unit is folded 2 by high temperature heater (HTH) 1, heat sound plate, room temperature cooler 3, and installs by being disposed in order shown in Fig. 2 and to form.Resonatron 4 is an isodiametric pipe, and two end faces all seal about it, metal bellows quality-spring assembly of the present utility model with it cut into about two sections, the assembly 1,2,3 of thermic sound unit is arranged in the pipe on resonatron 4 left sides.As further specifying of this embodiment, present embodiment provides a concrete structure size and relevant parameter designing, so that superiority of the present utility model to be described.In the present embodiment, the diameter of resonatron 4 is 50 millimeters, a segment length L on the left side ₁=0.2 meter, one section L on the right ₂Length can change.Adopt the stainless steel wave bellows spring 6 of solder type, coefficient of elasticity is 2400N/m (Newton/meter), and the quality of the mass 5 that welds together with spring is 0.2kg (kilogram).The working gas medium adopts helium, neon, argon gas and nitrogen respectively, and operating pressure is 2.0MPa.

Claims (3)

1, a kind of assembly that is used to reduce the thermoacoustic system resonant frequency comprises: at least one multiple layer metal bellows is characterized in that: also comprise a solid masses piece; Wherein the end face of solid masses piece is connected with a multiple layer metal bellows one end.

2. by the described assembly that is used to reduce the thermoacoustic system resonant frequency of claim 1; It is characterized in that: also be included in solid masses piece other end and be connected with a multiple layer metal bellows one end.

3. by claim 1 or 2 each described assemblies that are used to reduce the thermoacoustic system resonant frequency; It is characterized in that: described metal bellows can be the wavy metal bellows.

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