Modeling Partially Premixed Turbulent Combustion

This paper investigates combustion in the partially premixed regime that may be observed in non-premixed systems. Direct numerical simulation (DNS) is first utilized to further investigate the properties of diffusion flames at quenching along with the development of edge flames. DNS of spray flames are also performed and reveal the crucial role played by partially premixed combustion when liquid fuel injection is used. The ultimate product of this work is a flamelet model for partially premixed turbulent combustion that combines the flamelet models for non-premixed and premixed combustion. In addition, a new model for the turbulent burning velocity in partially premixed flows is proposed. The model is used to simulate the stabilization process of turbulent methane/air and propane/air jet diffusion flames.