Model for filtration combustion of carbon: Approximation of a thermodynamically equilibrium composition of combustion products

Abstract

A model for stationary filtration combustion of mixtures of carbon with a solid incombustible material in a counterflow a gas containing oxygen and a chemically inert gas is proposed. If the rates of chemical reactions in the combustion zone are sufficiently high, the ratio of carbon monoxide and dioxide in combustion products is assumed to be thermodynamically equilibrium at the combustion temperature. This assumption provides a closure for the balance equations for carbon, oxygen, and energy in the combustion front and gives explicit analytical expressions for the combustion temperature and composition of the products as functions of the composition of the carbon/inert mixture and of the gaseous oxidizer in stoichiometric regimes. Combustion modes are numerically calculated for a wide variation of the compositions. The upper limit of the reagent supply rate until which equilibrium relations can be used is found. A comparison of model predictions with experimental results shows their reasonable qualitative agreement.