A study of the weak shock wave propagating through an engine exhaust silencer system

Abstract

The present study addresses a computational work of the weak shock wave propagating inside a silencer system of automobile exhaust pipe. The second order total variation diminishing (TVD) scheme is employed to solve the two-dimensional, compressible, unsteady, Euler equations. Eight different models of the silencer systems are explored to investigate the effects of the silencer configuration that has on the weak shock wave propagation phenomena. The incident plane shock wave is assumed at the inlet of the silencer and its Mach number is changed between 1.01 and 1.30. The present computational analysis clearly reveals the detailed shock wave reflections/diffractions and vortical flows inside the silencer models. These results are detailed by the pressure time histories at several locations inside the silencer model. Of the eight different silencers applied, the silencer model with a series of the baffle plates inside the expansion chamber reduces the first peak pressure at the exit of the exhaust pipe by about 27%. The present computational results predict the experimental results with a quite good accuracy.