Turbulent Combustion Interaction Models for LES Simulations of High Speed Flow

This work will develop and validate a high-fidelity LES combustion model based on Flamelet Progress Variable approach for accurate prediction of high-speed turbulent combustion. The flamelet-modeling paradigm facilitates consideration of detailed reaction chemistry and complex turbulence-chemistry interaction, which is critical for high-speed hydrocarbon combustion. A work plan is proposed that integrates systematic model analysis using relevant DNS databases, algorithmic developments, and model validation against relevant experimental data. The Phase-II efforts will address critical modeling aspect that have been identified in Phase I in association with the prediction of JICF autoignition regimes, air-fuel mixing, and heat-transfer. To this end, it is proposed to develop and implement an unsteady flamelet progress-variable model in order to provide an accurate description of transient ignition regimes that are present in high-speed turbulent combustion regimes. To enable a computationally efficient chemistry representation technique that provides a rigorous error control, in situ adaptive tabulation (ISAT) will be employed. The unsteady flamelet-model will be extended to include the effect of heat losses. The models will be implemented in Cascade"s state-of-the-art unstructured LES solver, CharLES and it be used to simulate the HIFIRE Direct Connect Rig experiment for which a proof of concept LES was demonstrated in Phase I.