Combutational studies of end-wall flame quenching at low pressure: The effects of heterogeneous radical recombination and crevices

Abstract

A computational study of the effect of heterogeneous radical destruction and crevices on end-wall flame quenching in a lean CH4---O2---Ar mixture at low pressure has been performed. The unsteady conservation equations for a chemically reacting multicomponent gas have been solved with the commercially available partial differential equation solver package PDEPACK. Heterogeneous radical destruction at a cooled surface was found to have a minor effect on flame quenching compared to homogeneous destruction in the cooled flame gases near the surface. These results are in qualitative agreement with experiments performed in a side-wall geometry. Cooled crevices, however, had a much greater effect on the postquench oxidation of the fuel. Whereas the fuel layer left after quenching near a flat wall burns up more rapidly as the pressure is increased, unburned fuel left in a crevice after quencing burns up more slowly as the pressure is increased. This reaffirms the potential importance of crevices as sources of unburned hydrocarbons in an engine.