Flamelet modeling of lifted turbulent methane/air and propane/air jet diffusion flames

A flamelet model for partially premixed turbulent combustion combining flamelet models for non-premixed and premixed combustion was developed. A new model for the turbulent burning velocity in partially premixed flows was proposed. It was based on a formulation for a conditional turbulent burning velocity, which depends on mixture fraction. The impact of partially premixing was considered by employing the presumed pdf approach according to the mixture fraction. The same method was used to calculate mean scalar quantities on both sides of the premixed flame front. From a computational perspective, the model is beneficial because it ensures that the calculation of the chemical processes can be decoupled from the flow calculation. This facilitates simulations of realistic configurations while maintaining detailed chemistry. The model is utilized to simulate the stabilization process of turbulent methane/air and propane/air jet diffusion flames. The calculated lift-off heights compared favorably with experimental data from different authors. Original is an abstract.