Large eddy simulation of turbulent combustion by a dynamic second-order moment closure model

Abstract

A dynamic second-order moment closure model is developed for turbulent combustion in the form of large eddy simulation. The filtered reaction rate is directly closed in the form of Arrhenius law, and the whole temperature exponential function is treated as a single variable to avoid the traditional Taylor series expansion. The sub-grid unresolved reaction rate is modeled with a second-order moment closure model. All the coefficients in the sub-grid models are evaluated by the dynamic procedures. To validate and evaluate this model, a priori validation using a DNS database and posteriori validation by LES of the Sandia piloted jet flame (Flame D) and the Sydney bluff-body swirling flame (SM1) are performed. The results demonstrate that the dynamic second-order moment closure model coupled with LES is able to reasonably predict turbulent combustion even with simple chemistry, and has potential to predict more complex combustion with detailed reaction mechanism and acceptable computational cost.