COMBUSTION WAVE MICROSTRUCTURE IN HETEROGENEOUS GASLESS SYSTEMS

A novel method for studying the quantitative characteristics of combus tion wave microstructure has been developed. Using the combustion of t itanium and silicon powders as an example, the propagation of the comb ustion wave at the scale of microscopic heterogeneity is examined quan titatively for the first time. The variations in time and space of the combustion wave shape and propagation are studied experimentally. The sample porosity and the refractory reactant particle size are found t o affect the heterogeneity of the combustion wave. For low porosities and small particle sizes, the shape and propagation of the combustion wave at the microscopic level approach that observed at the macroscopi c level. However, for high porosities and large particle sizes, signif icant dispersion of the combustion front and local instantaneous veloc ities is observed at the microscopic level. A new relay-race mechanism of combustion wave propagation, that accounts for the heterogeneity o f the reactant medium, is suggested.