A Study On Multi-field Analysis Of An Exhaust Muffler

Exhaust noise is the main noise source that affects the vehicle pass-by noise. Installing exhaust muffler is an important technical measure of controlling noise. Because the research of the exhaust muffler involves the structural, acoustical and aerodynamic fields, so how to consider various factors to evaluate the comprehensive performance of the muffler is worth studying further.For a type of exhaust muffler, from the composite effect of structure, sound field and flow field, the coupling performance of exhaust muffler was studied. On this basis the improved solutions were put forward and the efficiency of the solutions was verified. The research done is as follows:(1) Based on the analysis software VIRTUAL.LAB, the finite element analysis of several simple muffler units has been discussed to study the characteristics of structural parameters on the sound field effects.(2) The acoustic mode of the simple muffler was analyzed under normal temperature and high temperature condition. The results show that the acoustic modal frequency increased and the sound pressure distribution basically remained unchanged on high temperature condition.(3) For the simple muffler, the influence of the elastic wall, temperature and airflow to the acoustic performance was analyzed, and the simultaneous effect of the factors on the sound field was also considered.(4) For a type of exhaust muffler, the spectrum characteristics of exhaust noise, the insertion loss of exhaust muffler and the simulation boundary conditions were obtained by engine bench test; on the basis of the FEM model, the fluid performance of exhaust muffler was studied, and the distribution of temperature, pressure, flow velocity and fluid regenerated noise were obtained; based on the research of the simple muffler by coupling study, the multi-field performance of exhaust muffler was analyzed and the improvements direction was determined preliminary.(5) Combined with acoustic characteristics of the simple muffler units and performance analysis of the original muffler, the insufficient performance was found, then the improvement program was proposed. The multi-field performance of improved muffler was analyzed by simulation method, through comparative analysis, results show that: the comprehensive performance has been greatly improved, which ensure the effectiveness of structural improvements.In summary, for the practical engineering problems, the multi-field performance of exhaust muffler was studied by using coupling analysis; the result provides some reference to improve the muffler. And its research and analysis methods have theoretical and practical value.