The Acoustic Attenuation Performance Of The Single-stage Three-cavities Muffler Between Lines

With the development of industry,the noise in the pipeline between large engineering equipment seriously affects the health of the workers in the surrounding area.At present,the effective measure is to increase the muffler between the pipeline systems.Muffler is an important research object in the field of noise control.The industrial pipeline is limited by the installation space,which requires large noise reduction and small design.In most cases,a single type of simple muffler can no longer make noise control at a reasonable level.In this paper,a single-stage three-cavity muffler used for pipeline is designed The main research contents include the following points:(1)The basic principle of the numerical simulation of sound field and the performance evaluation index of the noise reduction are briefly introduced.(2)Numerical simulation is used to analyze the influence of the structural parameters of the three kinds of mufflers on the sound attenuation performance of the simple expansion type,the inserted tube structure and the perforated pipe structure with the end closure.(3)In this paper,the single-stage three-chamber muffler is designed by combining advantages of some noise elimination structures.Based on the one-dimensional plane wave theory,the structure is divided into several simple structural mufflers,and the series and parallel relations among the sub units are determined.Finally,the transfer matrix of a single-stage three chamber muffler is obtained.The transfer loss of the mufflers is analyzed through the transfer matrix obtained,and the results are compared with those of numerical simulation,which coincides well with 4000 Hz frequency.The results of the two methods are analyzed by 1/3 octave spectrum respectively.The maximum relative error is 14.12% at the center frequency of 63~3150Hz and the total of 18 1/3 octave.(4)In order to further improve the muffler performance of the single-stage three-cavity muffler,inserted pipe is added between the designed single-stage three-cavity muffler chamber and cavity,and the influence of different length of insertion tube on the whole muffler performance of muffler is analyzed Finally,it is found that the increase of the insertion tube in the diffusion cavity can effectively improve the overall muffler performance of the muffler.When the length of the insertion tube is 1/2 of the length of the diffusion cavity,the sound attenuation performance in the 2000~3000Hz and the 4500~6000Hz frequency section is better.When the length of the insertion tube is 1/4 of the length of the diffusion cavity,the sound attenuation performance in the 3000~5000Hz frequency section is better.Two kinds of inserted pipe of different lengths are reflected in different frequency segments.Then the effect of the structure parameters of the hole on the perforated pipe in the diffusion cavity on the noise reduction performance was analyzed.(5)In order to verify the actual noise elimination performance of the designed muffler,the 3D printer is used to print the single-stage three-cavity muffler.Experimental measurements were made to test the actual noise elimination performance of three single stage three cavity mufflers with different structures.The measured data are analyzed in accordance with the frequency multiplier of 1/3 and compared with the number of numerical simulation,which has good agreement.(6)In order to analyze the aerodynamic performance of a single-stage three-cavity muffler,the flow field analysis of a single-stage three-cavity muffler with or without insert structure and two different length inserting pipes is carried out.The velocity distribution and pressure distribution of the three structures at different velocities are obtained.It is found that the insertion tube can effectively reduce the velocity mutation at the opening of the reflow plate and the resistance loss of the muffler at the same time of improving the muffler's noise reduction performance.(7)Considering the influence of the flow of the gas on the propagation of sound waves,the acoustic performance of the muffler is affected.Taking the length of the inserted tube length as the length of the diffusion cavity in the diffusion cavity as the 1/4 model,the acoustic field and the flow field of the muffler are coupled analyzed.The results show that the increase of the velocity can improve the noise reduction performance of the muffler below 1000 Hz,but the performance of the muffler at the high frequency is reduced by a small margin...