Prediction of turbulence in a motored DI diesel engine using a quasi-dimensional κ-ε model

In-cylinder turbulent flow in diesel engine is of importance due to its influence on fuel-air mixing, combustion, heat transfer and emissions. Several types of turbulent flow models-algebraic, quasi-dimensional and multi-dimensional have been reported in literature. The prediction of turbulent kinetic energy and its dissipation rate through appropriate equations have been attempted for compression process in multi-dimensional codes. However, such an approach has not found place in many multi-zone diesel combustion models. In this work, a quasi-dimensional k-ε model for turbulence prediction is attempted for DI diesel engine. The quasi-dimensional intake turbulence model eliminates the necessity of assuming the initial value of turbulent kinetic energy and its dissipation rate at the start of compression. The predictive capabilities of the model for intake and compression processes of a motored diesel engine are discussed in this paper. For compression process, the comparison of model predictions with available experimental data is found satisfactory.