Further development of the modified Eddy Dissipation Model

Abstract

The eddy dissipation model (EDM) has been used extensively in turbulent combustion modelling because of its simplicity, good convergence, and reasonable accuracy. A modified EDM model was developed to improve the accuracy of the model a few years ago. In the application for the jet flame and the opposed jet flame, it demonstrates very good accuracy. However, in the application for the bluff body diffusion flames, its accuracy is not good enough. In the current study, it is found out that the existence of wall of these flames influences the simulation accuracy. In the region near the wall, the ratio of turbulence dissipation rate to turbulent kinetic energy is too large and causing too high combustion reaction rate which is not realistic. By adding a limit to this ratio, the reaction rate near wall will be reasonable. The further developed modified version of EDM model gives very good prediction accuracy for the jet flow and the bluff body flow. With this near wall treatment, the modified EDM model will show good performance for internal combustion and free jet combustion.