Mathematical Modeling of Aluminum Diboride Combustion in an Air Flow

A mathematical model and the results of calculating the ignition and combustion of energetic condensed systems based on mono- and polydispersed aluminum diboride particles in air flows in constant-cross-section channels are reported. The kinetic characteristics of the transformations that separate aluminum diboride particles formed by gasification of energetic condensed systems undergo in a high-temperature oxidizing medium were determined using the dependences of the ignition induction period and combustion time on the air temperature and diameter and initial temperature of the particles. These dependences, in turn, were calculated using the model of parallel chemical reactions. The range of combustion conditions corresponding to the initial air temperatures from 300 to 2000 K and Mach numbers in the channel from 0.1 to 1.5 was considered. The influence of the aluminum diboride particle size and of the rate and initial temperature of the air flow on the combustion efficiency was demonstrated. The relationships between the combustion completeness factor of aluminum diboride particles at various initial parameters of the air flow and gasification products of energetic condensed systems at various fuel mixture equivalence ratios, corresponding to the diffusion and kinetic combustion, were determined. The conditions of the transition between the diffusion and kinetic control modes were found.