Effects of Transport Properties and Flow Non-Uniformity on the Temperature of Counterflow Diffusion Flames

Abstract

-An aerothcrmochemical analysis has been made on the counterflow diffusion flame established in the forward stagnation region of a porous cylinder and the effects of transport properties on the temperature of the flame are investigated. By making the flame sheet approximation and adopting a model in which the fuel and oxygen are treated as trace species while an inert gas is treated as a major species. general analytic expressions for the boundary layer properties are obtained for large as well as moderate rates of injection. Based on several numerical calculations, it is found that the flame sheet temperature varies not only with the ejection rate but also with transport properties such as the Lewis number, and that the effects of transport properties on the flame temperature become remarkable when the flame is located around the stagnation point. A comparison with experimental results shows that the present analysis well describes the results qualitatively.