Flow analysis in different geometries for optimization of exhaust manifold in a locomotive diesel engine

Abstract

A well-designed exhaust manifold has a positive effect on the efficiency of an engine and exhaust emissions. If the dimensions and geometric structure of the exhaust manifold are not designed in accordance with the pressure fluctuations of the fluid, this will have a negative effect on the velocity, temperature, density and pressure of the flow. In view of this and the high production costs of locomotive diesel engines, the pressure and velocity distributions in the exhaust manifold of a six-cylinder locomotive engine are investigated numerically in this study. Two different designs for the diesel engine are studied, taking into consideration the area in which the exhaust manifold will be mounted and the other engine parts. The pressure and velocity variations of the exhaust manifolds are compared via a computational fluid dynamics analysis, and analyses are performed using test data from a heavy-duty diesel engine at different power values (225, 450, 675, and 900 HP) and 1500 rpm, with the aim of finding the optimal design. Since the diameters at the cylinder outlets cannot be changed, the designs are created to fit within the existing area of the engine area The exhaust outlet is located in the middle of the manifold in the first model examined here, and is positioned close to the right-hand side of the manifold in the second model (the existing configuration). It is found that the flow becomes more efficient in the model in which the outlet is in the middle of the exhaust manifold.