Burning carbon particles in the presence of water vapor

Abstract

An earlier theoretical study of the dynamic behavior of a single carbon particle in a hot ambient is extended to include the effects of water vapor and hydrogen. Three heterogeneous reactions involving the consumption of carbon by oxygen, carbon dioxide, and water are included for both frozen and equilibrium chemistry in the gas phase. Predictions of rates of particle mass loss for specified ambient conditions and particle temperature and size suggest that in the high temperature or diffusion limit the influences of water vapor and oxygen on particle mass loss are approximately equivalent. However, in the kinetic limit, oxygen leads to higher rates of mass loss. Carbon dioxide and oxygen are not equally effective at any temperature. Prediction of the dynamic history of a cold particle suddenly immersed in a hot ambient indicates a more complicated situation in which the differences in energy balance of the particle permit neither water nor carbon dioxide to be equivalent to oxygen.