Pareto-efficient combustion modeling for improved CO-emission prediction in LES of a piloted turbulent dimethyl ether jet flame

Abstract

This study extends the Pareto-efficient combustion (PEC) framework to adaptive LES combustion simulations of turbulent flames. With the focus on improving predictions of CO emissions, PEC is employed to augment a flamelet/progress variable (FPV) model through local sub-model assignment of a finite-rate chemistry (FRC) model. A series of LES-PEC calculations are performed on a piloted partially-premixed dimethyl ether flame (DME-D), using a combination of FPV and FRC models. The drift term is utilized in the PEC framework to estimate the model error for quantities of interest. The PEC approach is demonstrated to be capable of significantly improving the prediction of CO emissions compared to a monolithic FPV simulation. The improved accuracy is achieved by enriching the FPV model with FRC in regions where the low-order model is determined insufficient through the evaluation of the drift term. The computational cost is reduced by a factor of two in comparison to the full finite-rate calculation, while maintaining the same level of accuracy for CO predictions.