Structural Optimization Design Of Engine Exhaust Muffler

The muffler is used as a noise reduction device widely installed in the car’s intake and exhaust passage,and can be used to muflle the noise in the pipeline through sound absorption linings attached to pipes and elbows or other noise reduction devices with discontinuous acoustic impedance.In the design of the muffler,it is necessary to reduce the exhaust resistance as much as possible while satisfying the noise reduction.Under actual conditions,the structure of the muffler is complicated,and exhaust resistance is increased to reduction of engine power.Therefore,based on the fluid analysis of the muffler,this paper improves the structure of the muffler,reduces the exhaust resistance,and does not affect the power of the normal operation of the engine.This paper introduces the acoustics of the gas exchange system and deduces the sound field equation of the muffler.At the same time,it based on the principles of the boundary condition setting using computational fluid dynamics computation and simulation based on the finite volume method.Then,according to the distribution of airflow velocity field,temperature field and pressure field inside the muffler,the fluid is calculated,and three types of typical structure muffler are studied and analyzed.Based on the flow field distribution characteristics of the respective structures,the internal flow field at a specific inlet velocity is calculated.Through research and analysis of the three typical types of muffler structures,it is concluded that there are large differences in the simulation results between the three because of different structures.This paper combining with the analysis of the anechoic flow field,a composite structure resistant muffler was studied.Through the simulation analysis of the flow field,the influence of the internal structure on the air velocity was studied.Based on the different length channels,the design parameters of the muffler were proposed.Orthogonal methods were designed.Based on the above,the three-dimensional model of the muffler is improved and optimized.It is found that the improved aerodynamic and acoustic performance of the muffler has been greatly improved.Finally,the acoustic performance and aerodynamic performance of the muffler are the main evaluation indicators,the simulation results are analyzed,and the optimal structure of different parameters is found out.And give a specific experimental design.This design process can greatly improve the design efficiency of the muffler,and has high economic efficiency,which provides a reliable reference for subsequent research.