KINETIC-MODEL FOR HYDROCARBON-ASSISTED PARTICULATE BORON COMBUSTION

A kinetic model is presented to describe the high temperature (1800 K < T < 3000 K) surface oxidation of particulate boron in a hydrocarbon combustion environment. The model includes a homogeneous gas-phase B/O /H/C oxidation mechanism consisting of 19 chemical species and 58 forw ard and reverse elementary reactions, multi-component gas-phase diffus ion, and a heterogeneous surface oxidation mechanism consisting of 'el ementary' adsorption and desorption reaction steps. Thermochemical and kinetic parameters for the surface reactions are estimated from avail able experimental data and/or elementary transition state arguments. T he kinetic processes are treated using a generalized kinetics code, wi th embedded sensitivity analysis, for the combustion of a one-dimensio nal (particle radius), spherical particle. Model results are presented for the oxidation of a 200 mum boron particle in a JP-4/air mixture a t ambient temperatures of 1400 K and 2000 K. These results include tem perature and gas-phase species profiles as a function of radial distan ce and particle burning rates. (C) 1994 John Wiley & Sons, Inc.