Simulation and Validation of IC Engine Swirl/Tumble Using Different Meshing Strategies

Swirl/tumble are rotational flow inside the combustion chamber. Fluent Computational Fluid Dynamics (CFD) software has been successfully used to simulate engine swirl and tumble flow. Two mesh approaches are possible within Fluent software to calculate transient engine swirl and tumble. One approach uses hybrid mesh with remeshing, while the other approach uses hex/wedge mesh with layering. The hybrid method employs tetrahedral remeshing, and is easier to set up compared to hex/wedge method for which only layering is used. Being easier to use, the hybrid method raises some concerns about result accuracy due to higher numerical diffusion associated with tet elements compared to the corresponding hex/wedge elements used for layering approach. This paper examines the two mesh approaches in terms of result accuracy for two engines, one SI and one diesel. The results are compared with PIV data for the SI engine. The impact of prism layers in the ports on the results are also investigated using these two engines