Analysis Of Acoustic Properties Of Muffler Based On COMSOL

Vehicle noise can not only increase the fatigue of drivers and occupants,but also affect the driving safety of vehicles,and bring about social problems such as environmental noise pollution.A large number of studies have shown that vehicle noise mainly comes from the aerodynamic exhaust noise generated by the engine,followed by engine noise and tire noise.As a device that can not only allow air flow through,but also reduce the noise propagation in the pipeline system,muffler has a good effect on reducing the exhaust noise of automobile engine,and it is also one of the most effective ways to reduce the noise of automobile.As an important index to evaluate the acoustic performance of mufflers,the acoustic performance of different types of mufflers is different,even if the structural parameters of the same type are different,their acoustic performance is different.In order to study the acoustic performance of different types of mufflers and the influence of structural parameters on the acoustic performance of mufflers,based on the acoustic theory of pipeline muffler system,the acoustic characteristics of its internal sound-absorbing materials and perforating elements and their effects on the acoustic performance of mufflers are analyzed and studied.The sound-absorbing materials and perforating elements sound-absorbing systems for vertical incidence are given.Based on the theoretical calculation method of number,COMSOL finite element software is used to simulate its sound absorption coefficient and study the influence of different structural parameters on its sound absorption performance.On this basis,the transmission loss of different types of mufflers is simulated based on the Helmholtz acoustic equation.The influence of different structural parameters on the acoustic performance of mufflers is studied and their muffling laws are obtained.Finally,based on the transfer function method of two microphones,the sound absorption coefficient of sound absorption materials,perforated elements and their combined structures are measured by experiments,and the theoretical rules of the simulation results are verified.The insertion loss of a motorcycle muffler is measured and simulated.The experimental results are in good agreement with the simulation results.Based on the existing research theory,its acoustic performance is optimized and simulated by COMSOL finite element software.Finally,the acoustic performance of the optimized structure is compared with that of the original muffler,which improves obviously in almost the whole frequency band,thus verifying the correctness of the theoretical rules and the validity of the simulation analysis.