Simulation of Combustion of Melting Energetic Materials.

To simulate the combustion of energetic materials (EM) with melting and surface evaporation. a one-dimensional transient model is formulated. In condensed phase, the model considers heat propagation and EMdecomposition via a first order reaction. In the gas phase, it considers heat propagation. species diffusion, exothermic decomposition of vapour via a first order reaction and exothermic conversion of gas components via a second order reaction. The boundary condition at the liquid-gas interface corresponds to equilibrium evaporation described by the Clausius-Clapeyron equation. The effects of melting and exothermicity of condensed phase reaction on the stability of combustion are studied. When simulating radiative ignition, it has been revealed that it can occur in one, two or three stages with different regimes of heat feedback from the gas phase. With relatively slow deradiation, a gas flame approaches the burning surface and sustained combustion is governed by heat feedback from the gas flame with burning rate several times higher than the gasification rate. With fast deradiation at high radiant fluxes the combustion extinguishes, indicating the impossibility of stable ignition under high heating rates. The limitations and possible improvements to the model are considered

Simulation of the dispersion and ignition of fine-dispersed aluminum particles by a gas generator

Using numerical modelling, we studied the formation and propagation of a cloud of fine-dispersed aluminum particles generated by a special unit under the action of high-temperature combustion products of a solid propellant gas generator, as well as the ignition conditions of these particles. The results of numerical modelling show that the dynamic characteristics of the cloud of particles and their ignition substantially depend on the temperature of gas generator combustion products, particle sizes, and the energy characteristics of the generator itself. The results obtained are in a qualitative agreement with experiments carried out at the Fraunhofer Institute for Chemical Technology (Pfinztal, Germany) [6]