Effect of radiant heat transfer on the minimum spark-ignition energy of gas suspensions

A mathematical model of spark ignition of a gas suspension is constructed o n the basis of a two-temperature thermal diffusion model of gas-suspension combustion and the radiant heat transfer is modeled in a diffusion approxim ation. The dependences of the minimum ignition energy on the parameters whi ch describe the disperse phase and the domain of the disperse-phase paramet ers in which the radiant heat transfer affects greatly the minimum spark-ig nition energy is determined by solving the problem numerically. The analyti cal formula that was obtained for determination of the critical spark-ignit ion energy of the gas suspension and that takes into account the radiant he at transfer in the gas suspension gives values different from numerical res ults by not more than 30% in a broad range of determining parameters of the problem. The theoretically obtained values of the minimum spark-ignition e nergy of a gas suspension of coal dust agree satisfactorily with experiment al data.