Design And Optimization Of Composite Micro-perforated Tube Muffler Based On Micro-perforated Panel

At present,fuel cell vehicles have gradually become the focus of various new energy vehicles.However,the noise problems caused by the side channel blowers in the air-assist system have to be solved.Because of the wideband,high frequency-based noise characteristics and clean,pollution-free operating conditions,conventional mufflers cannot effectively solve this noise.To solve these problems,this thesis presents a composite micro-perforated tube muffler,and through the theoretical calculations,finite element simulation and experimental methods,the muffler performance of the composite micro-perforated tube muffler is studied.The specific research content is as follows:First of all,the acoustic impedance and sound absorption coefficient of the microperforated plate structure are systematically and theoretically calculated,and the influence of different structural parameters on the sound absorption coefficient of micro-perforated plate structure was explored in detail.Including micropore diameter,micro-perforated plate thickness,perforation rate,cavity depth and other parameters.The theoretical model of the micro perforated plate structure is verified by finite element simulation and impedance tube test.Secondly,the transmission loss of the expansion muffler was deduced and the influence of the structural parameters on the muffler performance of the expansion muffler was explored.Then,Based on the micro-perforated plate structure theory and the perforated tube muffler,the theoretical model of the transmission loss of the microperforated tube muffler was deduced,and the theoretical model was validated using acoustic finite element software.A composite micro-perforated tube muffler model was proposed based on the noise characteristics produced by side channel blowers,the performance of micro-perforated tube mufflers and expansion mufflers.The microperforated tube length,micropore diameter,and micro-perforated plate thickness were investigated separately,and the transmission loss was tested and verified using the transmission loss test system platform.Finally,the structure of the composite microperforated tube muffler was optimized by orthogonal test.The performance of the optimized muffler model is obviously improved,and it can meet the noise reduction requirements of the side channel blowers.