Study of EGR Mixing in Intake Manifold Using 1D-3D CFD Coupled Solver Approach

EGR flow within individual cylinder as per requirement has a great importance which controls the performance and emissions of the diesel engine. The work presented here, elaborates the mixing process of EGR in the manifold with the fresh charge entering into intake manifold and then into cylinder. The study is carried on our three-cylinder diesel engine. For the simulation of such highly pulsating flow, the boundary conditions were generated from 1D model & in the back end the 3D CFD is used to solve the EGR mixing in a transient phase. The mixing at each cylinder port is evaluated using the Air and CO2 mass fraction at outlet of each intake port. Being a transient nature of valve operation, the EGR distribution within the manifold observed stabilized in 9 cycles. It was observed that the flow pulsations at the EGR inlet have large influence on the EGR distribution. For coupled CFD run, the Realizable k-ε model was used which is better suited for flow involving separation, moderate swirl, the mixing of species for turbulent & pulsating flows.