Intrinsic low-dimensional manifold (ILDM)-based concept for the coupling of turbulent mixing with manifold-based simplified chemistry for the turbulent flame simulation

Abstract

Manifold based simplified chemistry is an efficient reduction technique for the chemical kinetics, which aims to reduce the computational effort in numerical simulations. While the concept of reduced chemistry has been used for decades and various models have been developed up to now, their coupling with turbulent physical processes (e.g., mixing processes) has not been investigated extensively. This is attributed to the fact that the turbulent physical processes act as perturbation to the chemistry which pulls the thermo-kinetic states away from the manifold, and these states must relax back onto the manifold again. The present work gives insight into the coupling of reduced kinetic and the turbulent mixing processes. Accordingly, a strategy based on the Intrinsic Low-Dimensional Manifold concept is proposed. This coupling strategy is validated through the well-known Sandia Flame series. It is shown that the numerical results agree very well with those using detailed chemistry (no coupling model required) and experimental measurement. The suggested coupling strategy can be used for any manifold based simplified chemistry.