On the modeling of ignition processes of boron in the air

This study looks at single boron particle ignition macrokinetic processes in the high temperature air based on heat and mass transfer balance equations. Existence of parallel and competing processes of oxide film formation as a result of the chemical reaction and the film evaporation, heat release as a result of the chemical reaction, and heat exchange with the environment are taken in account. The study determined conditions at (0.1 … 4.0) MPa air pressure which underlied limiting processes of boron ignition because of oxidizer diffusion through the oxydic film. Also, we determined tempera- tures exceeding boric oxide boiling temperature, at which it is possible to ignore influence of these processes when calcu- lating boron particle ignition induction time. A boron particle total conversion time values in the air pressure variation range (0.1 … 4.0) MPa were computed.