Prediction of in-cylinder flow and heat transfer in direct-injection diesel engines.

This paper presents a method for predicting the local flow, heat transfer and wall temperature in the cylinder of a direct-injection diesel engine. A multidimensional model, using the conventional k-ε turbulence model, was employed for the prediction of in-cylinder phenomena. The model used a finite difference procedure with an expanding/contracting grid in axisymmetric representation. Fuel injection was described by an empirical formula of the spray. Combustion was treated, adopting experimental data of the heat release rate. The temperature distributions of the walls were calculated by another model of thermal analysis, using a finite element method, for the head, cylinder, and piston. Both models were coupled by boundary conditions, namely, wall functions. This computational method can be utilized to estimate heat transfer performance and to investigate the thermal effects of the engine design.