Simulation of Unsteady Turbulent Premixed Flame Propagation Using a Time-Accurate Pseudo-Compressibility Approach

Abstract

A preconditioning approach based on the artificial compressibility formulation is extended to solve the governing equations for unsteady turbulent reactive flows with heat release, at low Mach numbers, on an unstructured hybrid grid context. Premixed reactants are considered and a flamelet approach for combustion modeling is adopted using a continuous quenched mean reaction rate. An overlapped cell-vertex finite volume method is adopted as discretization scheme. Artificial dissipation terms for hybrid grids are explicitly added to ensure a stable, discretized set of equations. A second order, explicit, hybrid Runge-Kutta scheme is applied for the time marching in pseudo-time. A time derivative of the dependent variable is added to recover the time accuracy of the preconditioned set of equations. This derivative is discretized by an implicit, second order scheme. The resulting scheme is applied to the calculation of a test case consisting of an infinite planar (one-dimensional) flame propagating freely in both steady and unsteady manner. The results obtained with the proposed method agree with the data available in the literature.