Laminar Burning Velocities of Methane-Oxygen-Diluent Gas Mixtures

Abstract

The burning velocities of methane--oxygen--diluent mixtures were determined at atmospheric pressure by use of bunsen flames under laminar flow conditions. The fuel-lean region was investigated at theoretical flame temperatures of 2000, 2250 and 2500/sup 0/K employing nitrogen, helium and argon as diluents. By maintaining constant calculated flame temperatures for the different mixtures, evaluation of the effects of the properties of the diluent and of O/sub 2//CH/sub 4/ ratio was greatly simplified. The dependence of burning velocity on O/sub 2//CH/sub 4/ ratio was not in accord with the approximate theories of combustion. Therefore, an empirical expression was developed to describe the effect of diluent, O/sub 2//CH/sub 4/ ratio, and flame temperature on burning velocity. The evaluation of this expression is discussed in terms of effective transport properties and concentrations.