The effects of turbulence-induced time-periodic shear on a flame anchored to a propellant

We examine the combustion response of a flame anchored to two 1/4-spaces of solid fuel and oxidizer, a configuration relevant to the combustion of heterogeneous solid propellants. A time-periodic shear flow is applied to model the shear that can be generated by the presence of acoustics or turbulence in a rocket chamber. To estimate the magnitude and frequency of the shear for the case of a turbulent flow, we present DNS results of a planar periodic rocket, a configuration that has its roots in a multiscale analysis. Such a configuration allows for the determination of the shear parameters as a function of motor geometry and downstream location. The response of the flame to this shear, the heat flux to the surface, and the burning rate are calculated numerically. Significant enhancement to the burn rate, commonly known as erosive burning, is found. (C) 2008 The Combustion Institute. Published by Elsevier Inc. All rights reserved.