Search Results

Three dimensional CFD tools are commonly used to simulate spray injection and combustion in DI Diesel engines. However typical computations are strongly mesh dependent. By now it is not possible to enhance grid resolution since it would violate the underlying assumptions for the Lagrangian liquid phase description. Besides, a full Eulerian approach with an adapted mesh is not practical at the moment mainly because of prohibitive computer requirements. Based on the Lagrangian-Eulerian approach, new approaches have been developed: the Coupled Lagrangian-Eulerian (CLE) model for the two-way coupling between the spray and the air flow and a new combustion model (CFM3Z) which allows a description of the fuel-oxidizer sub-grid mixing. The previously introduced CLE model consists in retaining vapor and momentum along parcel trajectories as long as the mesh is insufficient to resolve the steep gradients created by the spray.