A discussion on the simplified volatile flame model for a solid particle

Abstract

Recent progress in experimental observation of volatile flames of coal particles renewed the interest on the modeling description of the single solid fuel particle combustion. A simplified modeling concept of volatile flame is based on the hypothesis of the thin flame sheet which surrounds the particle, thereby forming a volatile cloud. Pulverized fuel particles in a hot gas environment exhibit this complex interaction of the combined heat transfer, mass diffusion, and reactions of devolatilization and oxidation. This paper reviewed the main concepts of the simplified volatile flame model and showed the cases of quantitative evaluation of the parameters used in the physical modeling descriptions. Particle heat-up was modeled from the energy balance, volatiles released from the particle and oxygen diffused from the environment would react stoichiometrically at the flame, which would govern the mass and energy conservation. Although the formulation is complexly interrelated, and highly sensitive in a certain parameter range, mathematical modeling enabled to identify effects of the major parameters. Some of the observable quantities from the experiments were comparatively discussed with the parameters which could be quantified from the modeling.