Numerical Simulation of Exhaust Flows and Tailpipe Noise of a Small Single Cylinder Diesel Engine

The unsteady flows in the exhaust system of a single cylinder Diesel engine have been simulated by a 1-d fluid dynamic code, and the pulse noise spectrum radiated by the open termination has been calculated. The simulation model developed is based on different symmetric shock-capturing schemes for the solution of the 1-d conservation equations: the classical MacCormack and two-step Lax-Wendroff methods, and the new Conservation Element-Solution Element method (CE-SE). Several complex exhaust muffling systems have been modeled, such as Helmholtz resonators, expansion chambers, perforates, achieving a satisfactory agreement between predicted and measured results.