Wave action in the exhaust system of a supercharged two-stroke-engine model

Abstract The paper describes a theoretical and experimental investigation of wave action in a supercharged two-stroke-engine model. The theoretical analysis, by the method of characteristics, showed that for an infinite pipe the basic wave form consisted of two pulses, one due to the exhaust blowdown and the other due to the supercharge air. For a finite pipe the wave form was dependent on the fixings at the open end. The theory and the experiments showed that in a pipe with a plain open end the infinite pipe wave form was superseded by strong wave action with residual waves. With a nozzle at the open end the wave action was damped out, the residual waves were suppressed and the infinite pipe basic wave form was observed with some modifications due to reflected waves from the nozzle end. A study of the boundary conditions at the pipe ends showed that the flow into the pipe under unsteady conditions was different from the flow under steady conditions. At the outlet end the flow under steady and unsteady conditions was approximately the same.