Flame Quenching and Unburned Hydrocarbons on the Wall of a Spherical Combustion Vessel

Abstract

An experimental study on one-dimensional, laminar flame quenching on a cold wall was described herein. A homogeneous mixture of propane-air was ignited at the center of a spherical vessel, and the effects of pressure, mixture ratio and vessel size on the heat flux to the wall and on the unburned hydrocarbon concentrations were investigated. The characteristic values of quenching layer thickness defined from the maximum heat flux and the unburned hydrocarbon concentrations, δq and δ_HC, respectively, were determined. The value of δq was proportional to about minus 0.45 of the power of the pressure and was independent of the mixture ratio and the size of the combustion vessel. It was recognized that in the large size vessel, the hydrocarbons in the quench layer after the completion of combustion with flame propagation were oxidized. The value ofδ_HC obtained in the small size vessel was proportional to δq.