CN104677657B

CN104677657B - To the method that sound absorber formula silencer acoustical behavior measures side by side

Info

Publication number: CN104677657B
Application number: CN201410782203.0A
Authority: CN
Inventors: 方庆川
Original assignee: SHENZHEN ZHONGYA MECHANIC & ELECTRIC INDUSTRY Co Ltd
Current assignee: SHENZHEN ZHONGYA MECHANIC & ELECTRIC INDUSTRY Co Ltd
Priority date: 2014-12-16
Filing date: 2014-12-16
Publication date: 2017-12-05
Anticipated expiration: 2034-12-16
Also published as: CN104677657A

Abstract

A kind of simple and easy, measurement is accurately using Routine Test Lab to the ultra-large type method that sound absorber formula silencer acoustical behavior measures side by side.Step is as follows：1) elementary cell of silencer to be measured is determined；2) setting can enter the measuring unit that Routine Test Lab measures；3) when the upper limit that the length of silencer to be measured limits beyond Routine Test Lab measurement apparatus, by from the silencer to be measured corresponding to measuring unit simulating cut be the different measuring unit of two length；4) test of sound transmission loss, pneumatic noise acoustic power level and total pressure loss coefficient is carried out to measuring unit according to the method for the conventionally test.The present invention has following advantage：1) solving super large, sound absorber formula silencer can not enter the problem that Routine Test Lab measures side by side；2) at the scene before the installation sound absorber formula silencer side by side, can science and accurately prejudge the various uncontrollable environmental factors in erecting bed to influence and variable quantity caused by the muffler device parameter.

Description

To the method that sound absorber formula silencer acoustical behavior measures side by side

Technical field

The present invention relates to a kind of method for measuring silencer acoustical behavior, more particularly to one kind is to cannot be introduced into normal experiment The method that the silencer of the formula of sound absorber side by side of the unconventional size of room measures.

Background technology

With being on the increase for the continuous development of economic society, the rapid growth of scientific and technological strength and capital construction project, mesh Before, it is necessary to install substantial amounts of large-scale (referring to the section of complete machine and the silencer that length dimension is big) simultaneously in practical engineering application Sound absorber formula muffler device is arranged, but measures that there are the following problems to the acoustical behavioies of these large-scale silencers：

1) because package size is too big, such large-scale silencer cannot be introduced into Routine Test Lab and measure.

If 2) measured in erecting bed, shortcoming is：

A) because the muffler device has been installed in place, i.e. toilet survey acoustical behavior is bad, can not also carry out by a relatively large margin Adjustment, i.e., it is late；

B) due to environmental condition (the uncertain and environment back of the body of space size, shape and reflection characteristic of each erecting bed Scape noise etc.) it is different, the data measured at the scene to muffler device acoustical behavior are influenced by environmental conditions, survey number Larger according to uncertainty, therefore, the data can not accurately reflect the real internal performance of surveyed muffler device.That is, With the muffler device of a measurement data at the scene, the dependency number that site of deployment surveys data and other silencers mark is depended merely on It is that can not judge quality therebetween according to lateral comparison is carried out.

3) for component to be transported to the large-scale muffler device of field combinations completion, it is often necessary to be installed now according to specific The objective condition of field carries out necessary adjustment, the sound having in itself due to no accurate silencer to its part combination parameter Performance data is learned, therefore, it is impossible to which which kind of change adjustment described in scientific forecasting can produce to the Muffler Performance.

The content of the invention

The technical problem to be solved in the present invention is to provide a kind of simple and easy, measurement accurately using Routine Test Lab to nothing Method enters the ultra-large type method that sound absorber formula silencer acoustical behavior measures side by side in the laboratory.

In order to solve the above-mentioned technical problem, the technical solution adopted by the present invention is：

The present invention to the method that sound absorber formula silencer acoustical behavior measures side by side, including into Routine Test Lab The method for carrying out conventionally test to silencer afterwards, it is further comprising the steps of：

1) elementary cell of the silencer to be measured in practical application is determined before entering Routine Test Lab, the elementary cell For：In the case where keeping the silencer length constant, it is divided into if being about to silencer simulation by n row × m along its cross section Dry elementary cell, transverse shape, the size of each elementary cell are identical with the quantity of contained sound absorber and location, Described n, m are positive integer；

2) measuring unit measured into Routine Test Lab corresponding with the silencer, the measuring unit are set For：Formed by radix of the elementary cell by i rows × j row superpositions, the cross dimension of the measuring unit is Routine Test Lab The size that measurement apparatus allows access into, described i, j are positive integer；

3), will be with the noise elimination to be measured when the upper limit that the length of silencer to be measured limits beyond Routine Test Lab measurement apparatus The measuring unit simulating cut corresponding to device is the different measuring unit of two length, respectively the first length measurement unit and Second length measurement unit, wherein, the length of the first length measurement unit is L₁, the length of the second length measurement unit is L₂, point It is not：

First length measurement unit

Second length measurement unit

L₂The maximum measurement length that ＜ Routine Test Labs measurement apparatus allows；WithRespectively the silencer to be measured is basic The length of the air intake of contained sound absorber and outlet air end in unit；

4) according to the method for the conventionally test to the first length measurement unit L₁With the second length measurement unit L₂Enter The test of row sound transmission loss, pneumatic noise acoustic power level and total pressure loss coefficient.

The elementary cell quantity contained in the measuring unit is that the measuring unit cross dimension is conventional real for that can enter Test quantity corresponding to elementary cell number contained during the higher limit that room measures.

The elementary cell that the elementary cell of the silencer to be measured includes with measuring unit is elementary cell cross section congruence Relation.

The sound transmission loss TL of the silencer to be measured is obtained according to below equation_A：

TL_M1For the sound transmission loss of the first length measurement unit；

TL_M2For the sound transmission loss of the second length measurement unit；

The physical length for the section that absorbed sound for sound absorber in silencer to be measured.

The total pressure loss coefficient ξ of the silencer to be measured is obtained according to below equation_A：

ξ_M,1For the first length measurement unit L₁Total pressure loss coefficient；

ξ_M,2For the second length measurement unit L₂Total pressure loss coefficient；

The pneumatic noise acoustic power level L of described silencer to be measured is obtained according to below equation_W,A：

L_W,M：The pneumatic noise acoustic power level of measuring unit, is represented with dB；

S_A：The front face area of silencer to be measured, unit：m²；

S_M：The front face area of measuring unit, unit：m²；

H_A：The big side size in cross section of silencer to be measured, unit：m；

H_M：The big side size in cross section of measuring unit, unit：m；

λ：The wavelength of noise, unit：m.

Included when the elementary cell of the silencer to be measured with four similarity measure units for having been enter into Routine Test Lab Elementary cell has following relation：

1) it is elementary cell cross section similarity relation；

2) the net inflow area S of the elementary cell of silencer to be measured contained elementary cells in four similarity measure units For the net inflow area S of minimum₁It is maximum net inflow area S with contained elementary cell in four similarity measure units₂Between；

3) and there is a S₁＜ S ＜ S₂；0.90≤S₁/S₂When≤1.0；

4) elementary cell that four similarity measure units are included has following relation：

A. first similarity measure unit and second similarity measure unit are elementary cell cross section congruence relation, i.e., its Between elementary cell net inflow area equation and be the minimum net inflow area S₁；

B. the 3rd similarity measure unit and the 4th similarity measure unit are elementary cell cross section congruence relation, i.e., its Between elementary cell net inflow area equation and be the maximum net inflow area S₂；

C. first similarity measure unit and the 3rd similarity measure unit are elementary cell cross section similarity relation and same It is identical for the first described length measurement unit, i.e. two similarity measure element lengths；

D. second similarity measure unit and the 4th similarity measure unit are elementary cell cross section similarity relation and are The second described length measurement unit, i.e. two similarity measure element lengths are identical；

The sound transmission loss TL of the silencer to be measured is obtained in accordance with the following methods_A：

TL_M,S1：It is S for net inflow area₁, sound absorption length beSilencer sound transmission loss, represented with dB；

TL_M,S2：It is S for net inflow area₂, sound absorption length beSilencer sound transmission loss, represented with dB；

TL_M,L1,S1：For the sound transmission loss of the first similarity measure unit, represented with dB；

TL_M,L2,S1：For the sound transmission loss of the second similarity measure unit, represented with dB；

TL_M,L1,S2：Sound transmission loss for third phase like measuring unit, is represented with dB；

TL_M,L2,S2：For the sound transmission loss of the 4th similarity measure unit, represented with dB；

TL_A：The sound transmission loss of silencer to be measured, is represented with dB；

S：For the net inflow area of the elementary cell of silencer to be measured, unit：m²；

S₁：It is single for the net inflow area of elementary cell corresponding to the first similarity measure unit and the second similarity measure unit Position：m²；

S₂：It is single for the net inflow area of third phase elementary cell like corresponding to measuring unit and the 4th similarity measure unit Position：m²；

：The physical length for the section that absorbed sound for silencer to be measured；

：The length for the section that absorbed sound for the first similarity measure unit and third phase like measuring unit；

：The length for the section that absorbed sound for the second similarity measure unit and the 4th similarity measure unit.

When silencer length L to be measured is that can enter the length of Routine Test Lab, set in the following manner：

1) it is the 5th similarity measure unit of elementary cell cross section similarity relation and the 6th similar to take to silencer to be measured Measuring unit；

2) the net inflow area S of the elementary cell of silencer to be measured is between elementary cell contained by the 5th similarity measure unit Net inflow area S₁With the net inflow area S of contained elementary cell in the 6th similarity measure unit₂Between；

3) and there is a S₁＜ S ＜ S₂；0.90≤S₁/S₂When≤1.0；

4) length of the 5th similarity measure unit is identical with silencer length to be measured；

5) length of the 6th similarity measure unit is identical with silencer length to be measured；

TL_M,S1：For the sound transmission loss of the 5th similarity measure unit, represented with dB；

TL_M,S2：For the sound transmission loss of the 6th similarity measure unit, represented with dB；

TL_A：For the sound transmission loss of silencer to be measured, represented with dB；

S₁：For the net inflow area of the elementary cell of the 5th similarity measure unit, unit：m²；

S₂：For the net inflow area of the elementary cell of the 6th similarity measure unit, unit：m²；

：The physical length for the section that absorbed sound for silencer to be measured.

Included when the elementary cell of the silencer to be measured with two similarity measure units for having been enter into Routine Test Lab Elementary cell has following relation：

1) it is elementary cell cross section similarity relation；

2) the net inflow area S of the elementary cell of silencer to be measured is between elementary cell contained by the first similarity measure unit Net inflow area S₁With the net inflow area S of contained elementary cell in the second similarity measure unit₂Between；

3) and there is a S₁＜ S ＜ S₂；0.90≤S₁/S₂When≤1.0；

The pneumatic noise acoustic power level L of the silencer to be measured is obtained in accordance with the following methods_W,A：

L_W,A：For the pneumatic noise acoustic power level of silencer to be measured, represented with dB；

L_W,M,S1：For the pneumatic noise acoustic power level of E measuring units, represented with dB；

L_W,M,S2：For the pneumatic noise acoustic power level of F measuring units, represented with dB；

N：The ratio between number of the total elementary cell contained by with the test cell of elementary cell that silencer to be measured includes；

S：The net inflow area of the elementary cell of silencer to be measured, unit：m²；

S₁：For the net inflow area of the elementary cell contained by the first similarity measure unit, unit：m²；

S₂：For the net inflow area of the elementary cell contained by the second similarity measure unit, unit：m²。

1) it is elementary cell cross section similarity relation；

3)S₁＜ S ＜ S₂；0.90≤S₁/S₂During ＜ 1.0；

The total pressure loss coefficient ξ of the silencer to be measured is obtained in accordance with the following methods_A,r ：

Or,

ξ_M,p,1：For the total pressure loss coefficient of the first similarity measure unit；

ξ_M,p,2：For the total pressure loss coefficient of the second similarity measure unit；

ξ_M,q,1：Total pressure loss coefficient for third phase like measuring unit；

ξ_M,q,2：For the total pressure loss coefficient of the 4th similarity measure unit；

p：For the net inflow area ratio of first and second similarity measure unit：

q：For the net inflow area ratio of third and fourth similarity measure unit：

r：For the net inflow area ratio of silencer to be measured：

S₁：For the net inflow area of the elementary cell contained by first and second similarity measure unit, unit：m²；

S₂：For the net inflow area of the elementary cell contained by third and fourth similarity measure unit, unit：m²；

S₀：For the respective blocking area of elementary cell contained by four similarity measure units and silencer to be measured, unit：m²；

The physical length for the section that absorbed sound for silencer to be measured；

The length for the section that absorbed sound for first and third similarity measure unit；

The length for the section that absorbed sound for second, four similarity measure units.

The cross section simulation of large-scale silencer to be measured in practical application is divided into several elementary cells by the present invention, then According to the elementary cell determine that the measuring unit tested of Routine Test Lab measurement apparatus can be entered and the measuring unit is entered The test of row acoustical behavior.The associated acoustic performance data of silencer to be measured is obtained by the relevant test data of the measuring unit And the acoustical behavior data with other large-scale silencers of the silencer cross section to be measured similar conditions.I.e.：

1) by pair with silencer elementary cell to be measured be elementary cell congruence relation the survey into Routine Test Lab The test that unit carries out sound transmission loss, pneumatic noise acoustic power level and total pressure loss coefficient is measured, obtains the biography of the silencer to be measured Acoustic loss, pneumatic noise acoustic power level and total pressure loss coefficient.

2), will be to be measured with this when the length of silencer to be measured exceedes the maximum measurement length that normal experiment chamber device allows Silencer elementary cell is simulated and is divided into the first linear measure longimetry list along its length for the measuring unit of elementary cell congruence relation Member and the second length measurement unit, then by the first length measurement unit and the second length measurement unit are carried out sound transmission loss, The test of pneumatic noise acoustic power level and total pressure loss coefficient, obtain sound transmission loss, the air-flow of the silencer to be measured of random length Noisy acoustic power level and total pressure loss coefficient.

3) Routine Test Lab and each other first measuring unit and second of elementary cell similarity relation are had been enter into when two Individual measuring unit has：(1) first measuring unit is identical with the length of second measuring unit and is surveyed beyond Routine Test Lab Measure the upper limit that device limits；The net inflow area S of (2) first measuring unit elementary cells₁It is basic with second measuring unit The net inflow area S of unit₂, meet：0.90≤S₁/S₂, can be by first measuring unit and second during 1.0 relations of ＜ Measuring unit carries out the test of sound transmission loss, pneumatic noise acoustic power level and total pressure loss coefficient, obtains elementary cell and first Individual measuring unit and second measuring unit elementary cell similarity relation and net inflow area S meets each other：S₁＜ S ＜ S₂；0.90 ≤S₁/S₂Sound transmission loss, pneumatic noise acoustic power level and the total pressure loss coefficient of ＜ 1.0 other silencers to be measured.

The method of the present invention has following application advantage：

1) for the large-scale formula muffler device of sound absorber side by side, solve and remain to obtain without being moved into Routine Test Lab The problem of its accurate acoustical behavior data；

2) because the intrinsic associated acoustic performance data of acquired muffler device is more accurate, so, pacify at the scene Before filling the silencer, can science and accurately prejudge the various uncontrollable environmental factors in erecting bed to the muffler device parameter Caused influence and variable quantity.

Brief description of the drawings

Fig. 1 is one of silencer schematic cross-sectional view.

Fig. 2 is the two of silencer schematic cross-sectional view.

Fig. 3 is the three of silencer schematic cross-sectional view.

Fig. 4 is Fig. 1,2 schematic longitudinal section.

Fig. 5 is Fig. 3 schematic longitudinal section.

Fig. 6 is single sound absorber schematic longitudinal section.

Fig. 7 is that noise elimination cross section to be measured is cut into the elementary cell schematic diagram after several pieces.

Fig. 8 is by the stackable measuring unit schematic diagram of row by elementary cell by row.

Fig. 9 is discontinuous decay D in the derivation of equation of the present invention_SWith net inflow area S variation relation curve map.

Embodiment

The present invention to the method that sound absorber formula silencer acoustical behavior measures side by side, mainly utilize normal experiment Room test device measures to the acoustical behavior parameter of sound absorber silencer side by side, this side by side the transverse direction of sound absorber silencer or Longitudinal size, can be the dimensions that Routine Test Lab provides to enter, or the dimensions for providing to enter beyond Routine Test Lab.

Sound absorber formula silencer side by side, refer to the silencer for meeting following 3 features：

1) structure type of silencer, it is the parallel row of matrix expansion in 1 dimension or 2 dimension directions by one or more sound absorbers Row composition；As shown in Figure 1, 2, 3, typical vertical section is as shown in Figure 4,5 in its typical cross section；

2) acoustic attenuation performance of silencer, it is by the acoustic impedance of sound absorber sound absorption section surface, and the arrangement of sound absorber Spacing determines that each sound absorber is made up of along silencer length direction three parts, as shown in Figure 6 respectively windward side, sound absorption section And outlet air end, generally, the length of sound absorber is the length of silencer；

3) aerodynamic quality of silencer, i.e. pneumatic noise and pitot loss, by sound absorber both ends geometry and The number of the arrangement of surface roughness and sound absorber (density), spacing determine.

The measuring method of current ventilation silencer both domestic and external, predominantly following three kinds of methods：

1)ASTM E477/ISO 7235/GBT 25516；The laboratory of acoustics pipeline silencer and air channel terminal units is surveyed Amount method insertion loss, pneumatic noise and pitot loss；The acoustic muffler measuring methods of GBT 4760；

2)ISO 11691/GBT 16405；Insertion loss surveying laboratory letter under acoustics pipeline silencer airless state Yi Fa；

3)ISO 11820/GBT 19512；Acoustic muffler in-site measurement；

The major parameter of ventilation silencer performance is：Sound deadening capacity (insertion loss/sound transmission loss)/reproduced air-flow noise/pressure Power loses (resistance/resistance coefficient).Silencer measuring method of the prior art, it is all based on the silencer complete machine of independent completion Measurement, although ISO 7235/GBT 25516 annex E also describes the indirect measurement scheme for taking the test of specific section, With indirect measurement method proposed by the present invention, in the extensive and versatility of application, there is the difference of matter.

First, each nominal definition in method of the invention：

1st, elementary cell

In the case where the silencer length to be measured in keeping practical application is constant, along its cross section by the silencer to be measured Simulating cut, obtain some pieces of fritter section elements (i.e. the elementary cell be with determine cross section and with the silencer to be measured The unit of equal length), the position that each elementary cell transverse shape, size are identical and its sound absorber for including is how many and residing Put also identical, conversely, in units of the elementary cell, laterally consecutive arrangement n row, (n and m are vertical continuous arrangement m rows Positive integer) after can be restored to the identical silencer of silencer to be measured, the fritter section elements are defined as this and treated Survey the elementary cell (as shown in Figure 7) of silencer.

2nd, measuring unit

As shown in figure 8, using the elementary cell of silencer to be measured as radix, by i rows × j row (i, j are positive integer) Array forms several assembled units, such as：I rows × j row respectively equal to 1 × 1,1 × 2,2 × 2,2 × 3,3 × 3 etc..If at this One group or two groups of cross dimensions are chosen in dry assembled unit can enter the combination that Routine Test Lab test device is tested Measuring unit of the unit as the silencer to be measured.Currently preferred measuring unit be comprising the more combination of elementary cell Unit.

3rd, sound absorber congruence

It is all sound absorber structures in same silencer, big according to the definition of the foregoing formula silencer of sound absorber side by side Small all same；When being compared for two silencers, then different situations occur.Sound absorption in two silencers compared When body meets following condition, then it is sound absorber congruence to judge the sound absorber in this two silencers：

1) transverse shape of sound absorber is identical with size；

2) geometry of the air intake of sound absorber is identical with size, and surface roughness is identical；

3) geometry of the outlet air end of sound absorber is identical with size, and surface roughness is identical；

4) the vertical section shapes and sizes of the sound absorption section of sound absorber are identical, and surface roughness is identical and surface sound Impedance is identical；

5) sound absorber sound absorption segment length is identical.

4th, sound absorber is similar

Only the absorb sound length of section of two sound absorbers differs, and other Rule of judgment are identical with described sound absorber congruence.

5th, elementary cell cross section congruence

When being compared for the elementary cell cross sections of two silencers, when meeting following condition, then judge this two Elementary cell cross section in platform silencer is elementary cell cross section congruence：

1) transverse shape, size are identical；

2) quantity of the sound absorber included is identical；

3) sound absorber is congruent or similar；

4) position of the sound absorber in cross section is identical.

6th, elementary cell cross section is similar

When being compared for the elementary cell cross sections of two silencers, when meeting following condition, then judge this two Elementary cell cross section in platform silencer is similar for elementary cell cross section：

1) transverse shape；It is rectangle, the ratio of width to height is equal；

2) lateral dimension in cross section and vertical dimension is proportional zooms in or out；

3) quantity of the sound absorber included is identical；

4) sound absorber is congruent or similar；

5) position of the sound absorber in cross section is symmetrical with central, transverse axis and center vertical pivot；

6) the net inflow area ratio in cross section is between 0.9 to 1.0.

7th, elementary cell congruence

For the elementary cell of two silencers, when meeting following condition, then the substantially single of this two silencers is judged Member is elementary cell congruence：

1) it is elementary cell cross section congruence relation；

2) sound absorber included is sound absorber congruence relation.

When two elementary cells are elementary cell congruence relation, its front face area is equal, and blocking area is equal, net inflow Area equation, sound absorption girth is equal, and absorption area is equal.

8th, elementary cell is similar

For the elementary cell of two silencers, when meeting following condition, then the substantially single of this two silencers is judged Member is similar for elementary cell：

1) elementary cell is elementary cell cross section similarity relation；

2) sound absorber included is sound absorber congruence or similarity relation.

When two elementary cells are elementary cell similarity relation, its front face area, net inflow area, obstruction Area equation, sound absorption girth are equal.

9th, there is the following two kinds setting for the corresponding relation of silencer length to be measured and measuring unit：

1) isometric sound absorber measuring unit

If the length of silencer to be measured is less than or equal to the maximum length for allowing access into Routine Test Lab measurement, right with it The measuring unit answered is isometric sound absorber measuring unit.The length of i.e. described measuring unit preferentially selects the length.Namely Say, the measurement maximum length in laboratory is L_MAX, the length of the silencer to be measured of practical application is L, L≤L_MAX, then can be direct Length using the length L of silencer to be measured as measuring unit.

2) overlength sound absorber measuring unit

If, can will be corresponding during the upper limit that the length of silencer to be measured limits beyond Routine Test Lab measurement apparatus The length of sound absorber sound absorption section is divided into two parts, the respectively first sound absorption section in measuring unitWith the second sound absorption sectionWherein, First sound absorption sectionLength allow the minimum standard length (be usually 500mm) of test not less than Routine Test Lab measurement apparatus, Second sound absorption sectionLength not less than first sound absorption sectionTwice of length；

Determine again and the described first sound absorption sectionCorresponding first length measurement unit L₁With with described second sound absorption sectionIt is right The the second length measurement unit L answered₂, wherein,

First length measurement unit

Second length measurement unit

L₂The maximum measurement length that ＜ Routine Test Labs measurement apparatus allows；WithThe respectively silencer elementary cell In the air intake of contained sound absorber and the length of outlet air end.

2nd, the test of acoustical behavior is carried out to the measuring unit and estimates the associated acoustic performance for obtaining silencer to be measured Data

One) sound transmission loss/TL

1st, when the measuring unit and the silencer to be measured that enter laboratory elementary cell for elementary cell congruence relation and its When length is isometric sound absorber measuring unit, the sound transmission loss TL of silencer to be measured_AFor：

TL_A=TL_M

TL_A：The sound transmission loss of silencer to be measured in practical application, is represented with dB；

TL_M：The sound transmission loss for the measuring unit tested into laboratory, is represented with dB；

2nd, it is elementary cell cross section congruence pass when entering the measuring unit in laboratory with the elementary cell of silencer to be measured System and when its length is not etc., then the sound transmission loss TL of silencer to be measured_A(being represented with dB) is：

TL_M,1：For the first length measurement unit L₁Sound transmission loss, represented with dB；

TL_M,2：For the second length measurement unit L₂Sound transmission loss, represented with dB；

：The physical length for the section that absorbed sound for sound absorber in silencer to be measured, unit：m.

：The length for the section that absorbed sound for first length measurement unit；

：The length for the section that absorbed sound for second length measurement unit.

3rd, the present invention can be obtained substantially single by being measured to four measuring units with elementary cell similarity relation Member and the sound transmission loss of four measuring units silencer to be measured of elementary cell similarity relation each other.

I.e.：When the elementary cell of the silencer to be measured includes with four similarity measure for having been enter into Routine Test Lab units Elementary cell have following relation：

1) it is elementary cell cross section similarity relation；

3) and there is a S₁＜ S ＜ S₂；0.90≤S₁/S₂When≤1.0；

4th, the present invention can be obtained substantially single by being measured to two measuring units with elementary cell similarity relation Member and the sound transmission loss of two measuring units silencer to be measured of elementary cell similarity relation each other.

I.e.：When the elementary cell and two other sound absorber formulas side by side for having been enter into Routine Test Lab of the silencer to be measured The elementary cell that 5th similarity measure unit and the 6th similarity measure unit corresponding to silencer are included has following relation：

1) it is elementary cell cross section similarity relation；

2) net inflow of the net inflow area S of the elementary cell of silencer to be measured and the first similarity measure unit elementary cell Area S₁With the net inflow area S of the second similarity measure unit elementary cell₂, meet：S₁＜ S ＜ S₂；0.90≤S₁/S₂＜ 1.0 When；

3) when of length no more than Routine Test Lab measurement apparatus of silencer to be measured provides the higher limit entered；

Two) pneumatic noise acoustic power level/L_W

1st, normal conditions, pneumatic noise acoustic power level/L of silencer_WFor：

The constant that B-silencer pneumatic structure (shape and physical dimension) is associated, is represented with dB；

Peak Flow Rate (m/s) inside v-silencer；

C-the velocity of sound (m/s)；

Static pressure (Pa) in p-silencer；

Sectional area (the m of S-Peak Flow Rate point²)；

F-frequency (Hz)；

The maximal side of H-silencer section, unit are rice (m)；

For δ-regenerated noise in the characteristic parameter of high band, unit is rice (m)；

W₀- 1 (watt)；

According to above-mentioned formula, in theory, as long as two groups of difference wind speed v data of measurement, can obtain B and δ, so as to root According to the other specification of specific silencer, S, H, obtain different frequency f, pneumatic noise acoustic power level.

When actual measurement, the volume of data of multiple wind speed can be measured, returns relatively reliable B and δ parameter numbers Value.

The measuring unit similar by measuring two elementary cells, can find B and δ parameter values and net inflow area ratio Relation, so as to further obtain and the measuring unit that has measured other silencers of elementary cell similarity relation each other Pneumatic noise acoustic power level.

2nd, when it is elementary cell congruence relation to enter the measuring unit in laboratory with the elementary cell of silencer to be measured, this When face velocity it is equal, the pneumatic noise acoustic power level L of silencer to be measured_{W, A}It can be reduced to：

L_{W, M}：The pneumatic noise acoustic power level of measuring unit, is represented with dB；

S_A：The front face area of silencer to be measured, unit：m²；

S_M：The front face area of measuring unit, unit：m²；

H_M：The big side size in cross section of measuring unit, unit：m；

λ：The wavelength of noise, unit：m.

3rd, the present invention can be obtained substantially single by being measured to two measuring units with elementary cell similarity relation Member and the pneumatic noise acoustic power level of two measuring units silencer to be measured of elementary cell similarity relation each other.

I.e.：When the elementary cell of the silencer to be measured includes with two similarity measure for having been enter into Routine Test Lab units Elementary cell have following relation：

1) it is elementary cell cross section similarity relation；

3) and there is a S₁＜ S ＜ S₂；0.0≤S₁/S₂During ＜ 1.0；

The pneumatic noise acoustic power level L of the silencer to be measured is obtained in accordance with the following methods_W.M.S：

Three) total pressure loss coefficient/ξ

1st, when it is elementary cell congruence relation to enter the measuring unit in laboratory with the elementary cell of silencer to be measured, treat Survey the total pressure loss coefficient ξ of silencer_AFor：

ξ_A=ξ_M

ξ_A：The total pressure loss coefficient of silencer to be measured, dimensionless；

ξ_M：The total pressure loss coefficient of measuring unit, dimensionless.

2nd, it is elementary cell cross section congruence pass when entering the measuring unit in laboratory with the elementary cell of silencer to be measured System and when its length is not etc., then the total pressure loss coefficient ξ of silencer to be measured_AFor：

ξ_M,1：Sound absorption segment length beMeasuring unit total pressure loss coefficient, dimensionless；

ξ_M,2：It is for sound absorption segment lengthMeasuring unit total pressure loss coefficient, dimensionless；

：The length for the section that absorbed sound for sound absorber in silencer to be measured, unit：m.

3rd, the present invention can be obtained substantially single by being measured to four measuring units with elementary cell similarity relation Member and the total pressure loss coefficient of four measuring units silencer to be measured of elementary cell similarity relation each other.

1) it is elementary cell cross section similarity relation；

3)S₁＜ S ＜ S₂；0.90≤S₁/S₂During ＜ 1.0；

The total pressure loss coefficient of the silencer to be measured is obtained in accordance with the following methods

Or,

p：For the net inflow area ratio of first and second similarity measure unit；P=S₁/(S₁+S₀)；

q：For the net inflow area ratio of third and fourth similarity measure unit；Q=S₂/(S₂+S₀)

r：For the net inflow area ratio of silencer to be measured；R=S/ (S+S₀)

S₀：For the respective blocking area of elementary cell contained by four similarity measure units and silencer to be measured, unit：m² (note：Due to the elementary cells of elementary cell and silencer to be measured of four measuring units, elementary cell cross section is similar each other, because This its blocking area is equal)；

Each formula theoretical foundation in claims of the present invention：

-----------------------------------------------------

1. the derivation of equation of claim 4

Explained according to GB/T 20243/ISO 14163 full text and formula (4) and sound absorber formula silencer is determined side by side Justice, have

(4.a1)

In formula：The sound transmission loss of TL-- silencers, is represented with dB；D_s-- the discontinuous decay of silencer, represented with dB； D_a-- the propagation loss of silencer, represented with dB；-- the length (effective length) of silencer, unit are rice (m).

Therefore, length is respectively that the sound transmission loss of the silencer of sum is respectively：

(4.a2)

(4.a3)

Connection solves upper two formulas equation, obtains：

Therefore have：

2. the derivation of the formula of claim 5

According to fluid mechanics knowledge, with reference to the definition of sound absorber formula silencer side by side, and with reference to GB/T 20243/ISO The expression-form of 14163 formulas (10), formula (11), has

In formula：ξ_A-- the total pressure loss coefficient of silencer；The blocking area of d-- silencer sections, unit are square metre (m²)；The only logical area of s-- silencer sections, unit is square metre (m²)；The wetted perimeter (sound absorption girth) of P-- silencer sections, position For rice (m)；ξ₁-- silencer entrance flows backwards the resistance coefficient of cover；ξ₂-- muffler outlet flows backwards the resistance coefficient of cover；ξ₃-- eliminate the noise Device along journey coefficient of frictional resistance；-- the length (effective length) of silencer, unit are rice (m).

For the formula silencer of sound absorber side by side of elementary cell cross section congruence, d, s, P, ξ₁、ξ₂、ξ₃It is all identical, Therefore, above formula can be reduced to：

Two stylobate this cell cross-section congruences, the only silencer that length does not wait, length.Therefore,

In formula：ξ_{M, 1}-- effective length isThe total pressure loss coefficient of silencer；ξ_{M, 2}-- effective length isSilencer it is complete Press loss coefficient；K₁-- the coefficient of partial resistance of silencer inlet/outlet；K₂-- the frictional resistant coefficient of silencer；-- First The length (effective length) of silencer, unit are rice (m)；-- the length (effective length) of second silencer, unit is rice (m)。

Connection solves above-mentioned equation and obtained：

Thus,

3. the formula of claim 6

According to the formulas of GB/T 20243/ISO 14163 (13)

In formula,

L_WThe reproduced air-flow noise acoustic power level of-silencer, is represented with dB；

B-relevant with silencer type and frequency constant, is represented with dB；

Peak Flow Rate (m/s) inside v-silencer；

C-the velocity of sound (m/s)；

Static pressure (Pa) in p-silencer；

Sectional area (the m of S-Peak Flow Rate point²)；

F-frequency (Hz)；

The maximal side of H-silencer section, unit are rice (m)；

W₀- 1 (watt)；

For the measuring unit of elementary cell cross section congruence and the silencer of practical application, air-flow regeneration is caused to make an uproar The different affecting parameters of sound, are S and H, and formula (6.a1) can be converted into：

Therefore,

It can be obtained by formula (6.a4),

Wushu (6.a5) substitutes into formula (6.a3) and obtained,

That is formula (6.1)：

In formula,

For wavelength, unit：Rice (m).

4. profit requires 7 derivation of equation

When meeting S₁＜ S ＜ S2,When； (7.1)

According to the formulas of GB/T 20243/ISO 14163 (4) and formula (7)

According to the structure that sound absorber formula silencer defines side by side, its D that discontinuously decays_sChange with net inflow area S is closed It is that curve must be smooth continuous, therefore, when S consecutive variations, TL is also continuously to change, i.e.,：TL continuously may be used for S Lead.When three structure identicals, sound absorber formula silencer, its net inflow area have following relation side by side,

S₁＜ S ＜ S₂, and work as S₁Infinite approach S₂When, S₁≈S≈S₂,TL_s1≈TL_s≈TL_s2, therefore, work as S₁With S₂Difference Be worth sufficiently small or ratio it is close enough 1 when, linear interpolation can be used：

Substitute true value TL_s, as shown in figure 9,

5. the derivation of equation of claim 8

When meeting S₁＜ S ＜ S₂,When； (8.1)

With claim 7

6. the formula of claim 9

When meeting S₁＜ S ＜ S₂,When； (9.1)

According to the formulas of GB/T 20243/ISO 14163 (13)

In formula,

B-relevant with silencer type and frequency constant, is represented with dB；

Peak Flow Rate (m/s) inside v-silencer；

C-the velocity of sound (m/s)；

Static pressure (Pa) in p-silencer；

Sectional area (the m of S-Peak Flow Rate point²)；

F-frequency (Hz)；

The maximal side of H-silencer section, unit are rice (m)；

W₀- 1 (watt)；

When flow is constant,

From above formula, pneumatic noise L_{W, s}Change for aisle spare S and change be it is smooth continuous, will with right Ask 7

In formula (7.1) derivation it is similar, based on it is identical the reasons why, true value can be substituted with linear interpolation, with reference to figure 9, I.e.：

WhenWhen；

When the elementary cell quantity that the elementary cell quantity that the silencer of practical application is included is included by measuring unit N times when, no matter its section gross area or the net inflow gross area, be N times of measuring unit corresponding area.Therefore, when disconnected When surface current speed (face velocity) is identical,

7. the derivation of equation of claim 10

Or,

According to the formulas of GB/T 20243/ISO 14163 (10), (11), (12)

ξ=ξ_s+ξ_f (10.a1)

I.e.：

In formula,

ξ_sThe total coefficient of partial resistance of-silencer inlet/outlet；

ξ_f- silencer frictional resistant coefficient；

ξ₁- silencer arrival end coefficient of partial resistance；

ξ₂- muffler outlet end coefficient of partial resistance；

The blocking area of d-silencer section, square metre (m²)；

The circulation area of s-silencer section, square metre (m²)；

ξ₃The coefficient of frictional resistance of-silencer；

The effective length of-silencer, unit are rice (m)；

When there is 4 measuring units, net inflow area is respectively than r：P/p/q/q, absorb sound segment lengthRespectively：Measuring unit enter laboratory measurement pair and obtain its total pressure loss coefficient and be respectively：ξ_{M, p, 1}/ξ_{M, p, 2}/ ξ_{M, q, 1}/ξ_{M, q, 2}.Due to identical for the sound absorption body section of 4 measuring units, d is constant.Meanwhile

Moreover, entrance point kuppe, port of export kuppe are identical with sound absorption section surface, so, the ξ of 4 test cells₁、 ξ₂、ξ₃Identical, formula (10.a2) is transformed to：

Formula (10.a3) is transformed to：

Therefore,

Connection solves wherein 3 of above-mentioned 4 equations, can obtain,

Or,

Therefore,

Or,

Claims

1. it is a kind of to the method that sound absorber formula silencer acoustical behavior measures side by side, including offseted after entering Routine Test Lab The method that sound device carries out conventionally test, it is characterised in that：It is further comprising the steps of：

1) elementary cell of the silencer to be measured in practical application is determined before entering Routine Test Lab, the elementary cell are： In the case of keeping the silencer length constant, it is about to silencer simulation by n row × m along its cross section and is divided into several bases This unit, transverse shape, the size of each elementary cell are identical with the quantity of contained sound absorber and location, the n, M is positive integer；

2) measuring unit measured into Routine Test Lab corresponding with the silencer is set, the measuring unit is：With The elementary cell is that radix is formed by i rows × j row superpositions, and the cross dimension of the measuring unit is Routine Test Lab measurement dress The size allowed access into is put, described i, j are positive integer；

3), will be with the silencer pair to be measured when the upper limit that the length of silencer to be measured limits beyond Routine Test Lab measurement apparatus The measuring unit simulating cut answered is the different measuring unit of two length, respectively the first length measurement unit and second Length measurement unit, wherein, the length of the first length measurement unit is L₁, the length of the second length measurement unit is L₂, respectively For：

First length measurement unit

Second length measurement unit

<mrow> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>&GreaterEqual;</mo> <mn>2</mn> <mo>&times;</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> <mo>;</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> <mo>&GreaterEqual;</mo> <mn>500</mn> <mi>mm</mi> <mo>;</mo> </mrow>

L₂<The maximum measurement length that Routine Test Lab measurement apparatus allows；WithRespectively in the silencer elementary cell to be measured The air intake of contained sound absorber and the length of outlet air end；

4) according to the method for the conventionally test to the first length measurement unit L₁With the second length measurement unit L₂Passed The test of acoustic loss, pneumatic noise acoustic power level and total pressure loss coefficient.

2. according to the method for claim 1, it is characterised in that：The elementary cell quantity contained in the measuring unit is this Measuring unit cross dimension is elementary cell number pair contained when can enter the higher limit that Routine Test Lab measures The quantity answered.

3. according to the method for claim 2, it is characterised in that：The elementary cell of the silencer to be measured and measuring unit bag The elementary cell contained is elementary cell cross section congruence relation.

4. according to the method for claim 3, it is characterised in that：The transaudient of the silencer to be measured is obtained according to below equation Lose TL_A：

<mrow> <msub> <mi>TL</mi> <mi>A</mi> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mn>2</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> </mrow> <mrow> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> </mrow> </mfrac> <mo>+</mo> <mfrac> <mrow> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mn>2</mn> </mrow> </msub> <mo>-</mo> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> </mrow> <mrow> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> </mrow> </mfrac> <mo>&CenterDot;</mo> <mi>l</mi> </mrow>

TL_M,1For the sound transmission loss of the first length measurement unit；

TL_M,2For the sound transmission loss of the second length measurement unit；

5. according to the method for claim 3, it is characterised in that：The total head of the silencer to be measured is obtained according to below equation Loss coefficient ξ_A：

<mrow> <msub> <mi>&xi;</mi> <mi>A</mi> </msub> <mo>=</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> <mo>-</mo> <mfrac> <mrow> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mn>2</mn> </mrow> </msub> <mo>-</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> </mrow> <mrow> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> </mrow> </mfrac> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> <mo>+</mo> <mfrac> <mrow> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mn>2</mn> </mrow> </msub> <mo>-</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> </mrow> <mrow> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> </mrow> </mfrac> <mo>&CenterDot;</mo> <mi>l</mi> </mrow>

6. according to the method for claim 3, it is characterised in that：The gas of described silencer to be measured is obtained according to below equation Flow noise acoustic power level L_W,A：

<mrow> <msub> <mi>L</mi> <mrow> <mi>W</mi> <mo>,</mo> <mi>A</mi> </mrow> </msub> <mo>=</mo> <msub> <mi>L</mi> <mrow> <mi>W</mi> <mo>,</mo> <mi>M</mi> </mrow> </msub> <mo>+</mo> <mn>10</mn> <mi>l</mi> <mi>o</mi> <mi>g</mi> <mrow> <mo>(</mo> <mfrac> <msub> <mi>S</mi> <mi>A</mi> </msub> <msub> <mi>S</mi> <mi>M</mi> </msub> </mfrac> <mo>)</mo> </mrow> <mo>+</mo> <mn>10</mn> <mi>l</mi> <mi>o</mi> <mi>g</mi> <mo>&lsqb;</mo> <mn>1</mn> <mo>+</mo> <msup> <mrow> <mo>(</mo> <mfrac> <mi>&lambda;</mi> <mrow> <mn>2</mn> <msub> <mi>H</mi> <mi>A</mi> </msub> </mrow> </mfrac> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>&rsqb;</mo> <mo>-</mo> <mn>10</mn> <mi>l</mi> <mi>o</mi> <mi>g</mi> <mo>&lsqb;</mo> <mn>1</mn> <mo>+</mo> <msup> <mrow> <mo>(</mo> <mfrac> <mi>&lambda;</mi> <mrow> <mn>2</mn> <msub> <mi>H</mi> <mi>M</mi> </msub> </mrow> </mfrac> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>&rsqb;</mo> </mrow>

S_A：The front face area of silencer to be measured, unit：m²；

S_M：The front face area of measuring unit, unit：m²；

H_M：The big side size in cross section of measuring unit, unit：m；

λ：The wavelength of noise, unit：m.

7. according to the method for claim 2, it is characterised in that：When the elementary cell of the silencer to be measured has been entered with four Entering the elementary cell that the similarity measure unit of Routine Test Lab includes has following relation：

1) it is elementary cell cross section similarity relation；

2) the net inflow area S of the elementary cell of silencer to be measured contained elementary cells in four similarity measure units are most Small net inflow area S₁It is maximum net inflow area S with contained elementary cell in four similarity measure units₂Between；

3) and there is a S₁<S<S₂,When；

A. first similarity measure unit and second similarity measure unit are elementary cell cross section congruence relation, i.e., therebetween Elementary cell net inflow area equation and be the minimum net inflow area S₁；

B. the 3rd similarity measure unit and the 4th similarity measure unit are elementary cell cross section congruence relation, i.e., therebetween Elementary cell net inflow area equation and be the maximum net inflow area S₂；

C. first similarity measure unit and the 3rd similarity measure unit for elementary cell cross section similarity relation and are all institute The first length measurement unit stated, i.e. two similarity measure element lengths are identical；

D. second similarity measure unit and the 4th similarity measure unit are elementary cell cross section similarity relation and are described The second length measurement unit, i.e. two similarity measure element lengths are identical；

<mrow> <msub> <mi>TL</mi> <mi>A</mi> </msub> <mo>=</mo> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>S</mi> <mn>1</mn> </mrow> </msub> <mo>+</mo> <mfrac> <mrow> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>S</mi> <mn>1</mn> </mrow> </msub> <mo>-</mo> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>S</mi> <mn>2</mn> </mrow> </msub> </mrow> <mrow> <msub> <mi>S</mi> <mn>1</mn> </msub> <mo>-</mo> <msub> <mi>S</mi> <mn>2</mn> </msub> </mrow> </mfrac> <mo>&CenterDot;</mo> <mrow> <mo>(</mo> <mi>S</mi> <mo>-</mo> <msub> <mi>S</mi> <mn>1</mn> </msub> <mo>)</mo> </mrow> <mo>;</mo> </mrow>

<mrow> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>S</mi> <mn>1</mn> </mrow> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>L</mi> <mn>1</mn> <mo>,</mo> <mi>S</mi> <mn>1</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>L</mi> <mn>2</mn> <mo>,</mo> <mi>S</mi> <mn>1</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> </mrow> <mrow> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> </mrow> </mfrac> <mo>+</mo> <mfrac> <mrow> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>L</mi> <mn>2</mn> <mo>,</mo> <mi>S</mi> <mn>1</mn> </mrow> </msub> <mo>-</mo> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>L</mi> <mn>1</mn> <mo>,</mo> <mi>S</mi> <mn>1</mn> </mrow> </msub> </mrow> <mrow> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> </mrow> </mfrac> <mo>&CenterDot;</mo> <mi>l</mi> <mo>;</mo> </mrow>

<mrow> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>S</mi> <mn>2</mn> </mrow> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>L</mi> <mn>1</mn> <mo>,</mo> <mi>S</mi> <mn>2</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>L</mi> <mn>2</mn> <mo>,</mo> <mi>S</mi> <mn>2</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> </mrow> <mrow> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> </mrow> </mfrac> <mo>+</mo> <mfrac> <mrow> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>L</mi> <mn>2</mn> <mo>,</mo> <mi>S</mi> <mn>2</mn> </mrow> </msub> <mo>-</mo> <msub> <mi>TL</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>L</mi> <mn>1</mn> <mo>,</mo> <mi>S</mi> <mn>2</mn> </mrow> </msub> </mrow> <mrow> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> </mrow> </mfrac> <mo>&CenterDot;</mo> <mi>l</mi> <mo>;</mo> </mrow>

S₁：For the net inflow area of elementary cell corresponding to the first similarity measure unit and the second similarity measure unit, unit：m²；

S₂：For the net inflow area of third phase elementary cell like corresponding to measuring unit and the 4th similarity measure unit, unit：m²；

8. according to the method for claim 2, it is characterised in that：When silencer length L to be measured is that can enter Routine Test Lab Length when, set in the following manner：

1) the 5th similarity measure unit and the 6th similarity measure for elementary cell cross section similarity relation with silencer to be measured are taken Unit；

2) net flows of the net inflow area S of the elementary cell of silencer to be measured between elementary cell contained by the 5th similarity measure unit Logical area S₁With the net inflow area S of contained elementary cell in the 6th similarity measure unit₂Between；

3) and there is a S₁<S<S₂,When；

TL_{M, S1}：For the sound transmission loss of the 5th similarity measure unit, represented with dB；

9. according to the method for claim 2, it is characterised in that：When the elementary cell of the silencer to be measured has been entered with two Entering the elementary cell that the similarity measure unit of Routine Test Lab includes has following relation：

1) it is elementary cell cross section similarity relation；

2) net flows of the net inflow area S of the elementary cell of silencer to be measured between elementary cell contained by the first similarity measure unit Logical area S₁With the net inflow area S of contained elementary cell in the second similarity measure unit₂Between；

3) and there is a S₁<S<S₂,When；

<mfenced open = "" close = ""> <mtable> <mtr> <mtd> <mrow> <msub> <mi>L</mi> <mrow> <mi>W</mi> <mo>,</mo> <mi>A</mi> </mrow> </msub> <mo>=</mo> <msub> <mi>L</mi> <mrow> <mi>W</mi> <mo>,</mo> <mi>M</mi> <mo>,</mo> <mi>S</mi> </mrow> </msub> <mo>+</mo> <mn>10</mn> <mo>&CenterDot;</mo> <msub> <mi>log</mi> <mn>10</mn> </msub> <mi>N</mi> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>=</mo> <msub> <mi>L</mi> <mrow> <mi>W</mi> <mo>,</mo> <mi>M</mi> <mo>,</mo> <msub> <mi>S</mi> <mn>1</mn> </msub> </mrow> </msub> <mo>-</mo> <mfrac> <mrow> <msub> <mi>L</mi> <mrow> <mi>W</mi> <mo>,</mo> <mi>M</mi> <mo>,</mo> <msub> <mi>S</mi> <mn>1</mn> </msub> </mrow> </msub> <mo>-</mo> <msub> <mi>L</mi> <mrow> <mi>W</mi> <mo>,</mo> <mi>M</mi> <mo>,</mo> <msub> <mi>S</mi> <mn>2</mn> </msub> </mrow> </msub> </mrow> <mrow> <msub> <mi>log</mi> <mn>10</mn> </msub> <msub> <mi>S</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>log</mi> <mn>10</mn> </msub> <msub> <mi>S</mi> <mn>1</mn> </msub> </mrow> </mfrac> <mo>&CenterDot;</mo> <mrow> <mo>(</mo> <msub> <mi>log</mi> <mn>10</mn> </msub> <mi>S</mi> <mo>-</mo> <msub> <mi>log</mi> <mn>10</mn> </msub> <msub> <mi>S</mi> <mn>1</mn> </msub> <mo>)</mo> </mrow> <mo>+</mo> <mn>10</mn> <mo>&CenterDot;</mo> <msub> <mi>log</mi> <mn>10</mn> </msub> <mi>N</mi> </mrow> </mtd> </mtr> </mtable> </mfenced>

For the pneumatic noise acoustic power level of E measuring units, represented with dB；

For the pneumatic noise acoustic power level of F measuring units, represented with dB；

10. according to the method for claim 2, it is characterised in that：When the silencer to be measured elementary cell with four The elementary cell included into the similarity measure unit of Routine Test Lab has following relation：

1) it is elementary cell cross section similarity relation；

3)S₁<S<S₂,When；

<mfenced open = "" close = ""> <mtable> <mtr> <mtd> <mrow> <msub> <mi>&xi;</mi> <mrow> <mi>A</mi> <mo>,</mo> <mi>r</mi> <mo>,</mo> <mi>l</mi> </mrow> </msub> <mo>=</mo> <msup> <mrow> <mo>(</mo> <mfrac> <mrow> <mn>1</mn> <mo>-</mo> <mi>r</mi> </mrow> <mi>r</mi> </mfrac> <mo>)</mo> </mrow> <mn>2</mn> </msup> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>&CenterDot;</mo> <mo>&lsqb;</mo> <mfrac> <mrow> <mo>(</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>p</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>p</mi> <mo>,</mo> <mn>2</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> <mo>)</mo> <msup> <mi>p</mi> <mn>2</mn> </msup> </mrow> <mrow> <mo>&lsqb;</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>p</mi> <mo>)</mo> </mrow> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>q</mi> <mo>)</mo> </mrow> <mo>-</mo> <msup> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>p</mi> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>&rsqb;</mo> </mrow> </mfrac> <mo>&CenterDot;</mo> <mrow> <mo>(</mo> <mfrac> <mrow> <mi>r</mi> <mo>-</mo> <mi>q</mi> </mrow> <mrow> <mn>1</mn> <mo>-</mo> <mi>r</mi> </mrow> </mfrac> <mo>)</mo> </mrow> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>+</mo> <mfrac> <mrow> <mo>(</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>q</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>p</mi> <mo>,</mo> <mn>2</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> <mo>)</mo> <msup> <mi>q</mi> <mn>2</mn> </msup> </mrow> <mrow> <mo>&lsqb;</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>p</mi> <mo>)</mo> </mrow> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>q</mi> <mo>)</mo> </mrow> <mo>-</mo> <msup> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>q</mi> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>&rsqb;</mo> </mrow> </mfrac> <mo>&CenterDot;</mo> <mrow> <mo>(</mo> <mfrac> <mrow> <mi>r</mi> <mo>-</mo> <mi>q</mi> </mrow> <mrow> <mn>1</mn> <mo>-</mo> <mi>r</mi> </mrow> </mfrac> <mo>)</mo> </mrow> <mo>&rsqb;</mo> <mfrac> <mn>1</mn> <mrow> <mo>(</mo> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> <mo>)</mo> </mrow> </mfrac> <mo>+</mo> <mrow> <mo>(</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>p</mi> <mo>,</mo> <mn>2</mn> </mrow> </msub> <mo>-</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>p</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>&CenterDot;</mo> <mfrac> <mrow> <msup> <mi>p</mi> <mn>3</mn> </msup> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>r</mi> <mo>)</mo> </mrow> </mrow> <mrow> <msup> <mi>r</mi> <mn>3</mn> </msup> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>p</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>&CenterDot;</mo> <mfrac> <mi>l</mi> <mrow> <mo>(</mo> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> <mo>)</mo> </mrow> </mfrac> </mrow> </mtd> </mtr> </mtable> </mfenced>

Or,

<mfenced open = "" close = ""> <mtable> <mtr> <mtd> <mrow> <msub> <mi>&xi;</mi> <mrow> <mi>A</mi> <mo>,</mo> <mi>r</mi> <mo>,</mo> <mi>l</mi> </mrow> </msub> <mo>=</mo> <msup> <mrow> <mo>(</mo> <mfrac> <mrow> <mn>1</mn> <mo>-</mo> <mi>r</mi> </mrow> <mi>r</mi> </mfrac> <mo>)</mo> </mrow> <mn>2</mn> </msup> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>&CenterDot;</mo> <mo>&lsqb;</mo> <mfrac> <mrow> <mo>(</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>p</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>p</mi> <mo>,</mo> <mn>2</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> <mo>)</mo> <msup> <mi>p</mi> <mn>2</mn> </msup> </mrow> <mrow> <mo>&lsqb;</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>p</mi> <mo>)</mo> </mrow> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>q</mi> <mo>)</mo> </mrow> <mo>-</mo> <msup> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>p</mi> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>&rsqb;</mo> </mrow> </mfrac> <mo>&CenterDot;</mo> <mrow> <mo>(</mo> <mfrac> <mrow> <mi>r</mi> <mo>-</mo> <mi>q</mi> </mrow> <mrow> <mn>1</mn> <mo>-</mo> <mi>r</mi> </mrow> </mfrac> <mo>)</mo> </mrow> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>+</mo> <mfrac> <mrow> <mo>(</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>q</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>p</mi> <mo>,</mo> <mn>2</mn> </mrow> </msub> <mo>&CenterDot;</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> <mo>)</mo> <msup> <mi>q</mi> <mn>2</mn> </msup> </mrow> <mrow> <mo>&lsqb;</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>p</mi> <mo>)</mo> </mrow> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>q</mi> <mo>)</mo> </mrow> <mo>-</mo> <msup> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>q</mi> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>&rsqb;</mo> </mrow> </mfrac> <mo>&CenterDot;</mo> <mrow> <mo>(</mo> <mfrac> <mrow> <mi>r</mi> <mo>-</mo> <mi>p</mi> </mrow> <mrow> <mn>1</mn> <mo>-</mo> <mi>r</mi> </mrow> </mfrac> <mo>)</mo> </mrow> <mo>&rsqb;</mo> <mfrac> <mn>1</mn> <mrow> <mo>(</mo> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> <mo>)</mo> </mrow> </mfrac> <mo>+</mo> <mrow> <mo>(</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>q</mi> <mo>,</mo> <mn>2</mn> </mrow> </msub> <mo>-</mo> <msub> <mi>&xi;</mi> <mrow> <mi>M</mi> <mo>,</mo> <mi>q</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <mo>&CenterDot;</mo> <mfrac> <mrow> <msup> <mi>q</mi> <mn>3</mn> </msup> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>r</mi> <mo>)</mo> </mrow> </mrow> <mrow> <msup> <mi>r</mi> <mn>3</mn> </msup> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>q</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>&CenterDot;</mo> <mfrac> <mi>l</mi> <mrow> <mo>(</mo> <msub> <mi>l</mi> <mn>2</mn> </msub> <mo>-</mo> <msub> <mi>l</mi> <mn>1</mn> </msub> <mo>)</mo> </mrow> </mfrac> </mrow> </mtd> </mtr> </mtable> </mfenced>

p：For the net inflow area ratio of first and second similarity measure unit,

q：For the net inflow area ratio of third and fourth similarity measure unit,

r：For the net inflow area ratio of silencer to be measured,

：The length for the section that absorbed sound for first and third similarity measure unit；

：The length for the section that absorbed sound for second, four similarity measure units.