Influence of radiation on the critical heat-and mass-transfer conditions in parallel reactions at the surface of a particle

Analytical expressions are derived for the critical diameters bounding the region of high-temperature heat and mass transfer in parallel reactions at the surface of a particle. It is found that radiation with a large initial particle diameter leads to increase in the critical diameter of ignition with increase in the initial particle temperature. Formulas relating the combustion temperature and the particle diameter are derived. The influence of the prevailing conditions on the critical particle diameter at which spontaneous (induced) extinction and ignition occur is investigated in detail. An expression is obtained for the limiting gas temperature and oxidant content below which particle combustion is impossible. Degeneracy of the critical parameters of heterogeneous particle ignition and damping is investigated.