Microstructural mechanism of combustion in heterogeneous reaction media

Abstract

The process of combustion wave propagation in heterogeneous gasless reaction medium was studied experimentally. A novel technique of digital hight-speed microscopic video recording, which allows in situ observation of rapid (time resolution up to 10−4 s) processes occurring at the microscopic level (spatial resolution 1.7 μm), was used to investigate the combustion reaction in the Ti+ Si system. The experimental results clearly demonstrated that macroscopically steady propagation of the combustion wave proceeds microscopically through a sequence of sparks and extinctions (so-called scintillating reaction wave mode). The characteristics features and parameters of this propagation mode were studied and quantitatively analyzed. It was shown that experimentally observed complex behavior of the combustion wave at the microscopic scale is strongly correlated with microstructural characteristics of the reaction medium. Finally, it was demonstrated that description of heterogeneous combustion on the microscopic level fits well with effects observed on the macroscopic scale.