Impact of chemistry models on flame-vortex interaction

In numerical simulations of turbulent combustion, accurate modeling of the fuel chemistry is a critical component of capturing the relevant physics. Various chemical models are currently being used including detailed chemistry, tabulated chemistry, one-step chemistry, and rate-controlled constrained-equilibrium. However, the differences between these models and their impacts on the fluid dynamics are not well understood. Towards that end, the interaction between a laminar premixed hydrogen-air flame and a two-dimensional monopole vortex is investigated through simulations using the four previously-mentioned chemistry models. In these simulations, the flame speed, viscosity, diffusivity, conductivity, heat capacity, density ratio, and initial vortex characteristics are virtually identical providing a comparison of the effects of each chemical model alone. The results with each model are compared by considering the evolution of the flame structure and the characteristics of the vortex. All four models predict very similar results for the interaction with a small, fast vortex. In the interaction with a large, slow vortex, results from one-step chemistry are different due to a different flame thickness. The large, fast vortex case showcases differences in the flame structure and larger discrepancies between the modeling approaches. (C) 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.