EFFECT OF ZONING PARAMETERS ON DYNAMIC ZONE FLAMELET MODELING OF SUPERSONIC TURBULENT COMBUSTION

This paper presents a numerical simulation of the DLR supersonic combustor stabilized by a central strut, based on the dynamic zone flamelet model (DZFM) and the improved delayed detached eddy simulation (IDDES) turbulence model. The simulation of the combustion chamber under a non-reactive condition reproduces the complex wave structure and instability development of the central jet. The simulation results under the reactive condition successfully capture flame lift-off, OH radicals, average temperature, and other flame structural characteristics, thus validating the suitability of the numerical simulation method used in this study. Furthermore, it is observed from the distribution of reaction scalar (OH radical) in mixture fraction space that, the strong correlation between reaction scalar and mixture fraction is unavailable throughout the entire field. It is found that through introducing multi-zoning parameters such as flow direction coordinates, Mach number, and combustion heat release rate can significantly suppress the conditional fluctuation of the reaction state scalar in the mixed fraction space. Comparing the flame structure obtained by using the DZFM model with different multi-parameter-zoning strategies, it is found that in the tail region of the support plate and the high Reynolds number shear layer area, where the flame is in a premixed combustion state, the three-parameter zoning DZFM model including the combustion heat release rate and Mach number as zoning indicators, can significantly improve the accuracy of the model.