Effect of ignition conditions of fuel combustion

Abstract

The effect of ignition conditions upon the further development of the combustion wave is of great interest in the theory of nonstationary fuel combustion. A simplified concept of the ignition stage permits consideration of the entire process within Zel'dovich's model for nonstationary combustion of a powder with constant surface temperature. The present study attempts to formulate this problem, with consideration of the heat liberation produced by fuel decomposition during the heating process, and the difference between the kinetics of thermal decomposition and those of combustion. Combustion wave propagation is considered within the framework of a phenomenological model of nonstationary combustion, considering the change in fuel surface temperature. The process is studied by numerical solution for the case of fuel ignition by a flow of hot gas at constant pressure. It is shown that the transition of combustion from inflammation to the stationary regime is a unique special case of the problem of transition of combustion from one regime to another. If the depth of the heated layer in the s phase in the initial regime is much greater than that in the final regime, the original temperature distribution will not change significantly over the transition period. An analytical solution canmore » then be obtained for the nonstationary combustion rate.« less