Modeling of low-speed combustion of a methane-air-coal dust suspension

A plane one-dimensional problem of the propagation of slow-speed combustion in methane-air-coal dust suspensions is solved. Methane contained originally in the gas is assumed to burn-up completely in the flame front. The front velocity relative to the gas is calculated from relations derived in analysis of the stationary problem using the theory of thermal explosion. The gas suspension is regarded as a two-temperature and two-velocity medium. Heterogeneous reactions of carbon (coke) combustion and carbon monoxide reduction, and the yield of volatile components and their gas-phase combustion together with carbon monoxide are taken into account. Based on numerical calculations, the coal dust is shown to affect unambiguously the flame velocity, with moderate content of the dust. In lean mixtures, with a moderate content of the dust the intensity of the combustion wave increases and decreases under conditions close to stoichiometric ones.