CN102996302B - A kind of silencing apparatus simultaneously can eliminating wide band and narrow frequency band noise - Google Patents

Abstract

The present invention relates to silencing apparatus field, a kind of silencing apparatus simultaneously can eliminating wide band and narrow frequency band noise is specifically provided, it comprises an annular gas pipe, the interior pipe of described annular gas pipe is air-flow supervisor, in the outer tube of described annular gas pipe, at least two resonant cavities are set, the tube wall of described air-flow supervisor arranges perforation, and each resonant cavity to be responsible for described air-flow by boring a hole described at least one group and to be communicated with; The outer tube wall of described annular gas pipe is in series by same diameter or by two kinds and above different-diameter pipeline, uses baffle for separating between described resonant cavity.The present invention is by the aperture of the adjustment width of ring resonance, outer tube diameter and number and perforation and number, in conjunction with nonlinear least square method optimization resonant cavity width, diameter, number and the aperture of perforation and the more excellent combination of number, the effect eliminating wide band and narrow frequency band noise can be realized.And compact structure, occupy little space, under the prerequisite meeting acoustic attenuation performance, save space.

Description

A kind of silencing apparatus simultaneously can eliminating wide band and narrow frequency band noise

Technical field

The present invention relates to silencing apparatus field, particularly relate to a kind of silencing apparatus simultaneously can eliminating wide band and narrow frequency band noise.

Background technique

Automobile, as the important product in industrial products field, occupies very large share.But automobile enters the physical and mental health that heat-extraction system noise has a strong impact on people, therefore, the noise that air inlet system and exhaust system produce must be controlled.And the rational silencing apparatus of mounting structure controls one of most effective measures of inlet and exhaust system noise, current big-and-middle-sized diesel engine achieves supercharging substantially, and increasing petrol engine achieves supercharging.Supercharged engine brings new problem to the noise and vibration of automobile and road traffic noise.Can produce obvious howling during turbocharger operation, frequency range is approximately 1.5 ~ 4KHz, and frequency range is wider, needs effectively to suppress this noise.At present, measure automobile solving engine aspirating system noise mainly comprises arranges expansion silencing apparatus, Helmholtz silencing apparatus and some 1/4 wavelength tube, but because they can only eliminate the noise of single frequency band separately, wideband noise cannot be eliminated, and be subject to the restriction of mounting point, when meeting acoustical behavior, compact structure can not be accomplished.After considering the multinomial requirement such as space and environment, be necessary to realize wide band and narrow-band noise elimination with a compact silencer.

The design of current silencing apparatus is main or based on experience, lack complete design theory, the design cycle is long.The sound field that existing numerical computation method solves silencing apparatus inside often can not reflect the impact of structural parameter change on transmission loss in time efficiently, and prepares the process of anaphase from modeling in early stage, often lasts longer.In theoretical algorithm, what also do not propose for engineering is simple to operate, performs efficient algorithm.Therefore, be necessary to propose a kind of applicable engineering, for calculating the algorithm of the transmission loss of multi-cavity perforated muffler.This patent proposes a kind of innovatory algorithm based on Plane wave theory and transfer matrix method, and it can calculate the transmission loss in multiple chamber more accurately, and R. concomitans nonlinear least square method finds optimal solution more simultaneously.Flexibly, convenient, efficiently, the design efficiency of this type of silencing apparatus greatly can be improved.

Summary of the invention

For solving prior art Problems existing, the invention provides a kind of compact structure, wide band and narrow frequency band noise can be eliminated simultaneously, the simple silencing apparatus of structure.

The silencing apparatus simultaneously can eliminating wide band and narrow frequency band noise of the present invention, it comprises an annular gas pipe, the interior pipe of described annular gas pipe is air-flow supervisor, in the outer tube of described annular gas pipe, at least two resonant cavities are set, the tube wall of described air-flow supervisor arranges perforation, and each resonant cavity to be responsible for described air-flow by boring a hole described at least one group and to be communicated with; The outer tube wall of described annular gas pipe is in series by same diameter or by two kinds and above different-diameter pipeline, in order to increase the width of noise elimination frequency band, realizes wide band and narrow-band mixing noise elimination; Baffle for separating is used between described resonant cavity.

Described perforation is identical with the aperture in group.

Described silencing apparatus is made up of hexamethylene terephthalamide (PA6T/66).

Described silencing apparatus can realize eliminating wide band and narrow frequency band noise by the aperture of the adjustment width of resonant cavity, diameter and number and perforation and number.

Use the innovatory algorithm based on Plane wave theory and transfer matrix method, calculate the transmission loss of resonant cavity, and find resonant cavity width, diameter, number and the aperture of perforation and the more excellent combination of number in conjunction with nonlinear least square method.

The width of described resonant cavity is disposed in order from annular gas pipe one end to the other end is descending or ascending.

Penetration depth is determined by the wall thickness of described annular gas pipe, therefore changes penetration depth by adjustment wall thickness.

Preferably, the air-flow predominant tube diameter 41.6mm of described silencing apparatus, air-flow supervisor wall thickness 2.8mm, resonant cavity is five, resonant cavity width is respectively: 10.4mm, 13.8mm, 18.6mm, 15.2mm, 15.2mm, resonant cavity diameter is respectively: 69mm, 69mm, 69mm, 75mm, 75mm, the corresponding five groups of apertures circumferentially of five resonant cavities, the perforation that hole count is identical, the perforation hole count that each resonant cavity is corresponding is respectively: 28,28,28,20,20, aperture is respectively: 3mm, 3mm, 3mm, 2.5mm, 2.5mm.

Preferably, the air-flow predominant tube diameter 41.6mm of described silencing apparatus, air-flow supervisor wall thickness 2.8mm, resonant cavity is five, resonant cavity width is respectively: 10.5mm, 13.9mm, 17.2mm, 9.6mm, 9.6mm, resonant cavity diameter is respectively: 69mm, 69mm, 69mm, 75mm, 75mm, the corresponding five groups of apertures circumferentially of five resonant cavities, the perforation that hole count is identical, the perforation hole count that each resonant cavity is corresponding is respectively: 28,28,28,20,20, aperture is respectively: 3mm, 3mm, 2.9mm, 2mm, 2mm.

Preferably, the air-flow predominant tube diameter 41.6mm of described silencing apparatus, air-flow supervisor wall thickness 2.8mm, resonant cavity is five, resonant cavity width is respectively: 11.6mm, 13.6mm, 17.1mm, 9.6mm, 9.6mm, resonant cavity diameter is respectively: 69mm, 69mm, 69mm, 75mm, 75mm, the corresponding five groups of apertures circumferentially of five resonant cavities, the perforation that hole count is identical, the perforation hole count that each resonant cavity is corresponding is respectively: 30,28,36,20,20, aperture is respectively: 3mm, 2.6mm, 2.8mm, 2mm, 2mm.

The silencing apparatus simultaneously can eliminating wide band and narrow frequency band noise of the present invention, its beneficial effect is:

(1) main structure of silencing apparatus is an annular tracheae, interior pipe is air-flow supervisor, resonant cavity is set in appearance, by adjusting the width of ring resonance, the aperture of outer tube diameter and number and perforation and number, based on the innovatory algorithm of Plane wave theory and transfer matrix method, calculate the transmission loss of resonant cavity, and in conjunction with nonlinear least square method optimization resonant cavity width, diameter, number and the aperture of perforation and the more excellent combination of number, the effect eliminating wide band and narrow frequency band noise can be realized.The outer tube wall of annular gas pipe is in series by same diameter or two kinds and above different-diameter pipeline, in order to increase the width of noise elimination frequency band, realizes wide band and narrow-band mixing is eliminated the noise.

(2), multiple Helmholtz silencing apparatus profile series connection and integrated, compact structure, occupies little space, under the prerequisite meeting acoustic attenuation performance, save space.

Accompanying drawing explanation

This accompanying drawing illustrates that the picture provided is used for assisting the further understanding to invention, forms a application's part, does not form inappropriate limitation of the present invention, in the accompanying drawings:

Accompanying drawing 1 can eliminate the internal structure schematic diagram of the silencing apparatus of wide band and narrow frequency band noise for the present invention simultaneously.

Accompanying drawing 2 can eliminate the external structure schematic diagram of the silencing apparatus of wide band and narrow frequency band noise for the present invention simultaneously.

Accompanying drawing 3 is the transmission loss curve of the present invention without parameter optimization.

Accompanying drawing 4 is gas handling system noise reduction aim curve of the present invention.

Accompanying drawing 5 can eliminate the transmission loss curve after embodiment 1 parameter optimization of the silencing apparatus of wide band and narrow frequency band noise and aim curve for the present invention simultaneously.

Accompanying drawing 6 can eliminate the transmission loss curve after embodiment 2 parameter optimization of the silencing apparatus of wide band and narrow frequency band noise and aim curve for the present invention simultaneously.

Accompanying drawing 7 can eliminate the transmission loss curve after embodiment 3 parameter optimization of the silencing apparatus of wide band and narrow frequency band noise and aim curve for the present invention simultaneously.

Accompanying drawing 8 can eliminate the algorithm flow chart of the silencing apparatus of wide band and narrow frequency band noise for the present invention simultaneously.

Embodiment

The present invention will be described in detail with specific embodiment below, and be used for explaining the present invention in this illustrative examples of the present invention and explanation, but not as a limitation of the invention.

As shown in accompanying drawing 1,2, the silencing apparatus simultaneously can eliminating wide band and narrow frequency band noise of the present invention, comprise an annular gas pipe, the interior pipe 4 of described annular gas pipe is air-flow supervisor, arrange at least two ring resonances 3 in the outer tube 2 of described annular gas pipe, the tube wall of described air-flow supervisor 4 has perforation 1, and each ring resonance is responsible for 4 by perforation described at least one group with described air-flow and is communicated with, if each resonant cavity correspondence organizes perforation more, then circumference of boring a hole is evenly arranged in tube wall surrounding.Separate with toroidal membrane 5 between ring resonance 3.

The outer tube wall of described annular gas pipe is in series by same diameter or two kinds and above different-diameter pipeline, in order to increase the width of noise elimination frequency band, realizes wide band and narrow-band mixing is eliminated the noise.Described silencing apparatus is made up of hexamethylene terephthalamide (PA6T/66).

For the ease of manufacturing, the width of resonant cavity is disposed in order from annular gas pipe one end to the other end is descending or ascending.Penetration depth is determined by the wall thickness of described annular gas pipe, therefore changes by adjustment wall thickness the soundproof effect that penetration depth reached different.

Described silencing apparatus can realize eliminating wide band and narrow frequency band noise by the aperture of the adjustment width of ring resonance, diameter and number and perforation and number.

The innovatory algorithm that the present invention is based on Plane wave theory and transfer matrix method can calculate the transmission loss in multiple chamber more accurately, nonlinear least square method is used accurately to find the optimal solution of Different structural parameters combination, these computational methods can verify the transmission loss of existing structure, by changing parameter in real time, the sensitivity analysis that structure different designs parameter affects transmission loss can be carried out, facilitate design modifying, for the arrowband of different frequency section, the acoustic characteristics energy of broadband or arrowband and broadband combination, these computational methods can be fast, accurately find the optimal solution of Different structural parameters combination.

Based on the innovatory algorithm of Plane wave theory and transfer matrix method, the transmission loss calculating resonant cavity is as follows:

At perforated tube portion, the acoustic pressure and particle velocity in perforated pipe is respectively and is set to p ₁and u ₁, the acoustic pressure and particle velocity in resonant cavity is respectively p ₂and u ₂, under simple harmonic wave hypothesis, the ACOUSTIC WAVE EQUATION in perforated pipe and in resonant cavity is respectively:

$\frac{{\∂}^2{p}_1}{{\∂x}^2}+\frac{M_1}{M_1-1}({j2k}_0+\frac{4}{\mathrm{d\ξ}})\frac{{\∂p}_1}{\∂x}+\frac{1}{M_1^2-1}(\frac{{j4k}_0}{\mathrm{d\ξ}}-k_0^2)p_1-\frac{M_1}{M_1^2-1}\frac{4}{\mathrm{d\ξ}}\frac{{\∂p}_2}{\∂x}-\frac{1}{M_1^2-1}\frac{{j4k}_0}{\mathrm{d\ξ}}{p}_2=0---\left(1\right)$

$\frac{{\∂}^2{p}_2}{{\∂x}^2}+\frac{M_2}{M_2-1}({j2k}_0+\frac{4d}{(D^2-d^2)\mathrm{\ξ}})\frac{{\∂p}_2}{\∂x}+\frac{1}{M_2^2-1}(\frac{{j4\mathrm{dk}}_0}{(D^2-d^2)\mathrm{\ξ}}-k_0^2)p_2-\frac{M_2}{M_2^2-1}\frac{4d}{(D^2-d^2)\mathrm{\ξ}}\frac{{\∂p}_1}{\∂x}-\frac{1}{M_2^2-1}\frac{{j4\mathrm{dk}}_0}{(D^2-d^2)\mathrm{\ξ}}{p}_1=0---\left(2\right)$

In formula: ρ ₀c ₀ξ is the perforation acoustic impedance of perforated pipe, and utilization perforation acoustic impedance sets up the acoustic pressure relation ρ in perforated pipe and in resonant cavity ₀c ₀ξ=(p ₁-p ₂)/u, u is the particle vibration velocity in perforated pipe, k ₀for wave number, M ₁, M ₂for in perforated pipe with the Mach number in resonant cavity.

By computing and abbreviation, the transfer matrix at perforated pipe two ends is obtained to formula (1) and (2):

$\left\{\begin{array}{c}{p}_1\left(0\right)\\ {\mathrm{\ρ}}_0{c}_0{u}_2\left(0\right)\end{array}\right\}=\left[T\right]\left\{\begin{array}{c}{p}_1\left(l_p\right)\\ {\mathrm{\ρ}}_0{c}_0{u}_2\left(l_p\right)\end{array}\right\}---\left(3\right)$

By formula (3) and then the transmission loss of trying to achieve single resonant cavity

$\mathrm{TL}=20{\log }_{10}\left(\frac{1}{2}\right|T_{11}+T_{12}+T_{21}+T_{22}\left|\right)---\left(4\right)$

If this silencing apparatus is many structure of resonant cavity, then total transfer matrix is:

$\left[T\right]=\left[T_N\right]\·\·\·\left[T_i\right]...\left[T_1\right]=\left[\begin{array}{cc}{T}_{N,11}& T_{N,12}\\ T_{N,21}& T_{N,22}\end{array}\right]\·\·\·\left[\begin{array}{cc}{T}_{i,11}& T_{i,12}\\ T_{i,21}& T_{i,22}\end{array}\right]\·\·\·\left[\begin{array}{cc}{T}_{\mathrm{1,11}}& T_{\mathrm{1,12}}\\ T_{\mathrm{1,21}}& T_{\mathrm{1,22}}\end{array}\right]---\left(5\right)$

By the transmission loss of formula (4) and (5) and then many structure of resonant cavity be:

$\mathrm{TL}=20{\log }_{10}\left(\frac{1}{2}\right|T_{N,11}+T_{N,12}+T_{N,21}+T_{N,22}\left|\right)+...+20{\log }_{10}\left(\frac{1}{2}\right|T_{i,11}+T_{i,12}+T_{i,21}+T_{i,22}\left|\right)$

(6)

$+...+20{\log }_{10}\left(\frac{1}{2}\right|T_{\mathrm{1,11}}+T_{\mathrm{1,12}}+T_{1.21}+T_{1.22}\left|\right)$

Utilize nonlinear least square method as follows to the basic ideas finding optimal solution:

$\underset{x}{\min }\mathrm{sum}\left\{\mathrm{func}{(f,X)}^2\right\}---\left(7\right)$

func(f,X)=objection(f)-Transimission_Loss(f,X);

In formula, objection (f) is aim curve, and wherein f is frequency; Transimission_Loss (f, X) is the curve that will optimize, and f is frequency, and X is superior vector.

Based on this algorithm flow chart as shown in Figure 8.

Optimized project and result are below provided, arrange:

The structural parameter of a, initial wideband noise silencing apparatus: resonant cavity diameter d out=69mm, air-flow predominant tube diameter din=41.6mm, air-flow supervisor wall thickness tw=2.8mm, resonant cavity number num=5, remaining variables data are as table 1:

Table 1 wide band initializaing variable parameter value table

B, initial narrow frequency band noise acoustic wave filter structure parameter (invariant): resonant cavity diameter d out=75mm, air-flow predominant tube diameter din=41.6mm, air-flow supervisor wall thickness tw=2.8mm, resonant cavity number num=2, remaining variables is as table 2:

Table 2 narrow-band initializaing variable parameter value table

Above-mentioned innovatory algorithm is used to calculate transmission loss:

Transmission loss curve is as calculated as accompanying drawing 3, be loaded into gas handling system noise reduction aim curve as accompanying drawing 4, as can be seen from Figure 4, the transmission loss curve be not optimized can not meet this silencing apparatus and require that silencing apparatus can eliminate the acoustical demands of narrow-band and wideband noise.

In order to realize eliminating wide band and narrow frequency band noise simultaneously, each parameter is optimized, optimized variable is set, determine the optimization range of variable:

First, select the number of optimized variable, in order to take into account engineering demand, three kinds of schemes be set:

(1) resonant cavity is wide variable, piercing aperture and hole count immutable.

(2) resonant cavity is wide, and piercing aperture is variable, and hole count is immutable.

(3) resonant cavity is wide, and piercing aperture, hole count are all variable.

Embodiment 1

(1) kind scheme of choosing is optimized, and namely resonant cavity is wide variable, piercing aperture and hole count immutable.

Table 3 is the wide band dimension constraint value table of setting:

Table 3 wide band dimension constraint value table

Table 4 is narrow-band dimension constraint table:

Table 4 narrow-band dimension constraint value table

After optimizing, obtain the optimum results of parameter as table 5:

Table 5 optimum results

Transmission loss curve after optimization and aim curve are as accompanying drawing 5, and as can be seen from the figure, contrast with aim curve, Optimal Curve meets aim curve substantially, and the silencing apparatus after therefore optimizing can meet eliminates wide band and narrow frequency band noise simultaneously.

Therefore the eliminated narrow-band of the present embodiment after optimizing and the acoustic wave filter structure parameter of wideband noise are:

Air-flow predominant tube diameter 41.6mm, air-flow supervisor wall thickness 2.8mm, resonant cavity number 5, its diameter is respectively: 69mm, 69mm, 69mm, 75mm, 75mm, corresponding resonant cavity width is respectively: 10.4mm, 13.8mm, 18.6mm, 15.2mm, 15.2mm, each resonant cavity correspondence five groups aperture circumferentially, the perforation that hole count is identical, the perforation hole count that five resonant cavities are corresponding is respectively: 28,28,28,20,20, and corresponding piercing aperture is respectively: 3mm, 3mm, 3mm, 2.5mm, 2.5mm.

Embodiment 2

(2) kind scheme of choosing is optimized, and resonant cavity is wide, and piercing aperture is variable, and hole count is immutable.

Table 6 is the wide band dimension constraint value table of setting:

Table 6 wide band dimension constraint value table

Table 7 is narrow-band dimension constraint table:

Table 7 narrow-band dimension constraint value table

After optimizing, obtain the optimum results of parameter as table 8:

Table 8 optimum results

Transmission loss curve after optimization and aim curve are as accompanying drawing 6, and as can be seen from the figure, contrast with aim curve, Optimal Curve meets aim curve substantially, and the silencing apparatus after therefore optimizing can meet eliminates wide band and narrow frequency band noise simultaneously.

Therefore the eliminated narrow-band of the present embodiment after optimizing and the acoustic wave filter structure parameter of wideband noise are:

Air-flow predominant tube diameter 41.6mm, air-flow supervisor wall thickness 2.8mm, resonant cavity number 5, its diameter is respectively: 69mm, 69mm, 69mm, 75mm, 75mm, corresponding resonant cavity width is respectively: 10.5mm, 13.9mm, 17.2mm, 9.6mm, 9.6mm, each resonant cavity correspondence five groups aperture circumferentially, the perforation that hole count is identical, the perforation hole count that five resonant cavities are corresponding is respectively: 28,28,28,20,20, aperture is respectively: 3mm, 3mm, 2.9mm, 2mm, 2mm.

Embodiment 3

(3) kind scheme of choosing is optimized, and resonant cavity is wide, and piercing aperture is variable, and hole count is immutable.

Table 9 is the wide band dimension constraint value table of setting:

Table 9 wide band dimension constraint value table

Table 10 is narrow-band dimension constraint table:

Table 10 narrow-band dimension constraint value table

After optimizing, obtain the optimum results of parameter as table 11:

Table 11 optimum results

Transmission loss curve after optimization and aim curve are as accompanying drawing 7, and as can be seen from the figure, contrast with aim curve, Optimal Curve meets aim curve substantially, and the silencing apparatus after therefore optimizing can meet eliminates wide band and narrow frequency band noise simultaneously.

Therefore the eliminated narrow-band of the present embodiment after optimizing and the acoustic wave filter structure parameter of wideband noise are:

Air-flow predominant tube diameter 41.6mm, air-flow supervisor wall thickness 2.8mm, resonant cavity number 5, its diameter is respectively: 69mm, 69mm, 69mm, 75mm, 75mm, corresponding resonant cavity width is respectively: 11.6mm, 13.6mm, 17.1mm, 9.6mm, 9.6mm, the corresponding five groups of apertures of each resonant cavity, the perforation that hole count is identical, the perforation hole count circumferentially that five resonant cavities are corresponding is respectively: 30,28,36,20,20, aperture is respectively: 3mm, 2.6mm, 2.8mm, 2mm, 2mm.

Embodiment 4:

The setting of above optimized variable is not limited only to above-mentioned numerical value, according to actual conditions parameters numerical value, also can select other scheme, use this method to be optimized.

Above the technological scheme that the embodiment of the present invention provides is described in detail, apply specific case herein to set forth the principle of the embodiment of the present invention and mode of execution, the explanation of above embodiment is only applicable to the principle helping to understand the embodiment of the present invention; Meanwhile, for one of ordinary skill in the art, according to the embodiment of the present invention, embodiment and application area all will change, and in sum, this description should not be construed as limitation of the present invention.

Claims (3)

1. can eliminate a silencing apparatus for wide band and narrow frequency band noise simultaneously, it is characterized in that:

Comprise an annular gas pipe, the interior pipe of described annular gas pipe is air-flow supervisor, arrange at least two resonant cavities in the outer tube of described annular gas pipe, the tube wall of described air-flow supervisor arranges perforation, and each resonant cavity to be responsible for described air-flow by boring a hole described at least one group and to be communicated with;

The outer tube wall of described annular gas pipe is in series by same diameter or by two kinds and above different-diameter pipeline, in order to increase the width of noise elimination frequency band, realizes wide band and narrow-band mixing noise elimination; Can realize eliminating wide band and narrow frequency band noise by adjusting the width of resonant cavity, the aperture of diameter and number and perforation and number;

With baffle for separating between described resonant cavity, the aperture of boring a hole in same group is identical, and the wall thickness by adjustment air-flow supervisor changes penetration depth;

Described silencing apparatus is made up of hexamethylene terephthalamide;

The air-flow supervisor internal diameter 41.6mm of described silencing apparatus, air-flow supervisor wall thickness 2.8mm, resonant cavity is five, resonant cavity width is respectively: 10.4mm, 13.8mm, 18.6mm, 15.2mm, 15.2mm, resonant cavity external diameter is respectively: 69mm, 69mm, 69mm, 75mm, 75mm, the corresponding five groups of perforation circumferentially of five resonant cavities, the perforation hole count that each resonant cavity is corresponding is respectively: 28,28,28,20,20, aperture is respectively: 3mm, 3mm, 3mm, 2.5mm, 2.5mm.

2. can eliminate a silencing apparatus for wide band and narrow frequency band noise simultaneously, it is characterized in that:

Comprise an annular gas pipe, the interior pipe of described annular gas pipe is air-flow supervisor, arrange at least two resonant cavities in the outer tube of described annular gas pipe, the tube wall of described air-flow supervisor arranges perforation, and each resonant cavity to be responsible for described air-flow by boring a hole described at least one group and to be communicated with;

The outer tube wall of described annular gas pipe is in series by same diameter or by two kinds and above different-diameter pipeline, in order to increase the width of noise elimination frequency band, realizes wide band and narrow-band mixing noise elimination; Can realize eliminating wide band and narrow frequency band noise by adjusting the width of resonant cavity, the aperture of diameter and number and perforation and number;

With baffle for separating between described resonant cavity, the aperture of boring a hole in same group is identical, and the wall thickness by adjustment air-flow supervisor changes penetration depth;

Described silencing apparatus is made up of hexamethylene terephthalamide;

The air-flow supervisor internal diameter 41.6mm of described silencing apparatus, air-flow supervisor wall thickness 2.8mm, resonant cavity is five, resonant cavity width is respectively: 10.5mm, 13.9mm, 17.2mm, 9.6mm, 9.6mm, resonant cavity external diameter is respectively: 69mm, 69mm, 69mm, 75mm, 75mm, the corresponding five groups of perforation circumferentially of five resonant cavities, the perforation hole count that each resonant cavity is corresponding is respectively: 28,28,28,20,20, aperture is respectively: 3mm, 3mm, 2.9mm, 2mm, 2mm.

3. can eliminate a silencing apparatus for wide band and narrow frequency band noise simultaneously, it is characterized in that:

Comprise an annular gas pipe, the interior pipe of described annular gas pipe is air-flow supervisor, arrange at least two resonant cavities in the outer tube of described annular gas pipe, the tube wall of described air-flow supervisor arranges perforation, and each resonant cavity to be responsible for described air-flow by boring a hole described at least one group and to be communicated with;

The outer tube wall of described annular gas pipe is in series by same diameter or by two kinds and above different-diameter pipeline, in order to increase the width of noise elimination frequency band, realizes wide band and narrow-band mixing noise elimination; Can realize eliminating wide band and narrow frequency band noise by adjusting the width of resonant cavity, the aperture of diameter and number and perforation and number;

With baffle for separating between described resonant cavity, the aperture of boring a hole in same group is identical, and the wall thickness by adjustment air-flow supervisor changes penetration depth;

Described silencing apparatus is made up of hexamethylene terephthalamide;

The air-flow supervisor internal diameter 41.6mm of described silencing apparatus, air-flow supervisor wall thickness 2.8mm, resonant cavity is five, resonant cavity width is respectively: 11.6mm, 13.6mm, 17.1mm, 9.6mm, 9.6mm, resonant cavity external diameter is respectively: 69mm, 69mm, 69mm, 75mm, 75mm, the corresponding five groups of perforation circumferentially of five resonant cavities, the perforation hole count that each resonant cavity is corresponding is respectively: 30,28,36,20,20, aperture is respectively: 3mm, 2.6mm, 2.8mm, 2mm, 2mm.