Flame propagation velocity in an aerosuspension of nanoscale aluminum powder

A mathematical model of the combustion of aero-suspension of nanodispersed aluminum powder is presented. Modeling of the combustion of aluminum nanoparticles is implemented using the local mathematical model of the oxidizer diffusion through aluminum oxide layer on the surface of the particle with account for its reaction with aluminum. The rate of oxidation of aluminum particles and the associated rate of heat release are determined from the solution of local problems on the combustion of aluminum nanoparticles. The state parameters of the aero-suspension of aluminum nanoparticles in the air are determined from the solution of the system of equations of energy conservation for gas and particles, and the equation of mass conservation for components of the gas-dispersed mixture. A developed model does not require specification of the ignition temperature of aluminum nanoparticles.
Numerical solution of the stated problem allowed one to obtain the dependence of the propagation velocity of combustion front on the mass concentration of nanodispersed aluminum powder in the air and on the initial temperature of aluminum powder. Propagation velocity of combustion front was found to increase with increasing initial temperature and mass concentration of the powder.