Mean gas flow and temperature gradient in calculation for the performance of automobile silencer

Engine exhaust noise is one of the main sources of automobile noise,and using of silencer is an important method controlling exhaust noise. In this paper, two new sound field transmission matrixes for silencing elements are established. In calculating the silencer performance, mean gas flow and temperature gradient are considered, and the effect of flow velocity is studied with three dimensional spectrum. A muffler performance calculation program is also established. Calculation results were compared with test results and good agreement was obtained,but exactitude of calculation and test should be further raised.