Computational analysis of turbulence enhancement in a compression ignition engine with modified inlet design.

This study aims to enhance the turbulence of direct injection (DI) diesel engine by modifying the inlet manifold design with an inclined nozzle-like provision angles of 30°, 60°, and 90° along with its regular intake system. Numerical analysis was carried out using the computational fluid dynamics package (STAR-CD libraries of es-ice) to study the flow field and combustion characteristic with the modified intake manifold geometries. The computational investigation was carried out for both single and double pass conditions at 1500 rpm under high-load operating condition (5.2 kW). The computational results showed that the velocity magnitude of modified single pass intake manifold increases by about 10% that results in higher turbulence even near the point of fuel injection. Through the modification in the inlet manifold, the combustion parameters such as in-cylinder pressure and in-cylinder temperature are increased as compared to the standard manifold for the same quantity of fuel injected per cycle. In summary, the 60° modified manifold with a single pass shows better combustion and emission characteristics compared to that of regular inflow manifolds due to the improvement in turbulence levels.