Mathematical simulation of heterogeneous detonation of coal dust in oxygen with allowance for the ignition stage

A consistent physicomathematical model that describes ignition and detonation combustion of a gas suspension of coal-dust particles is developed. The model is based on the concepts of the two-velocity two-temperature continuum of mechanics of heterogeneous media with allowance for reduced reactions of pyrolysis, combustion of volatiles, and combustion of the coke residue. The model is verified with the use of available experimental data on the dependence of the detonation velocity on the initial concentration of the discrete phase and the dependence of the ignition delay on the Mach number of the incident shock wave. An analysis of ignition of the gas suspension of bituminous coal in shock waves shows that the stage of ignition proceeds under conditions of both temperature and velocity nonequilibrium. The influence of particle heating due to stagnation temperature on devolatilization dynamics and ignition delay is established. Examples of computed flow structures behind shock and detonation waves with allowance for the ignition stage are presented.