Modeling nonpremxed turbulent combustion is a formidable task due to coupling between the thermochemical equations and the three-dimensional Navier-Stokes equations. There is a strong incentive to decouple the chemistry problem from the turbulence. Laminar flamelet modeling is a salient approach to decoupling, and is often used in current combustion modeling. The principal objective of the proposed research is the investigation of the validity of laminar flamelet modeling of turbulent diffusion flames The approach to this scientific objective is to perform direct numerical simulation of turbulent diffusion flame cases. The research via simulations will be combined with theoretical investigations in one of the cases when the chemistry is kept simple. In order to investigate a realistic model of hydrogen flames the partial equilibrium chemistry model will be implemented in conjunction with the 3D Navier-Stokes equations. The analytic investigations will be performed in interaction with ongoing laboratory work elsewhere. Improved understanding of the validity of laminar flamelet modeling will significantly contribute to turbulent flame modeling efforts, with eventual applications to critical issues in combustion systems such as ignition and pollutant formation.
