Flow characterisation in an exhaust manifold of a single-cylinder internal combustion engine (ICE)

Abstract

This paper presents an investigation of flow characteristic inside the exhaust manifold that were designed with different bending angle (BA), bending radius (BR) and pipe diameter (Dp ). Five exhaust manifold models were developed and analysed by the computational fluid dynamic (CFD) method. Accordingly, the pressure distribution, velocity streamline and backpressure values were observed. The simulation results showed a different flow pattern for all five models, indicating the manifold design affect the flow characteristic inside the exhaust system. The results demonstrated that the pressure distribution inside the exhaust manifold is influencing its velocity streamline pattern, that directly effecting the outlet velocity of the exhaust gas. From this work, a small bending angle with a short straight pipe has led to a smoother exhaust flow and even exhaust velocity across the model. The results obtained from the simulation can be used as a guide to improve the understanding of the flow behaviour in the manifolds and might be used to improve the manifold design.