A Multi-Fluid CFD Turbulent Entrainment Combustion Model: Formulation and One-Dimensional Results

Meeting the increasingly stringent regulations for spark-ignited (SI) internal combustion engines requires understanding the complex chemical and physical processes that occur during combustion. Short time scales and extremes in temperature and pressure make detailed measurements in real combustion systems difficult. To augment the experimental measurements numerical models for combustion have been developed. These models can provide insight into the non-linear interactions that occur during combustion and help to guide the design of the system by providing information on parameters that cannot be measured directly.

This paper presents a newly-developed turbulent combustion model that is based on the concepts of the turbulent entrainment model. Quasi-dimensional engine simulations have used models of this type for the past two decades with considerable success. In this study, the model is formulated in a manner suitable for coupling with CFD solvers in one or more spatial dimensions. The existing reaction rate model is retained, but the motion of the entrainment surface is now described using front-tracking techniques. The result is a multi-fluids based turbulent combustion model that incorporates the effects of both the local scale and intensity of the turbulence. The model formulation and preliminary results are presented and discussed.