In this study, a one-equation LES sub-grid model from Menon, et al. [5] is used in simulating the diesel combustion process. In addition, based on the one-equation methodology of Menon et al., a new one-equation LES scalar transport model is formulated. These models allow for the turbulent transfer coefficients for both momentum and scalar flux to be determined independent of each other. The turbulent viscosity, μt, is determined as a function of the sub-grid kinetic energy, which is in turn determined from the one-equation model. The formulation for the scalar transfer coefficient, μs, is similar to that of the turbulent viscosity, yet is made to be consistent with scalar transport.
Results for the LES momentum transfer are compared to experimental data of a backward facing step. This model, in conjunction with the LES scalar flux model, is verified by comparing with experimental data for a non-reacting turbulent jet. Finally, these models are used with a Probability Density Function (PDF) combustion model to model the diesel combustion process. The presented results indicate that that LES is a viable option for simulating the turbulent reacting processes that occur within the diesel environment.
