Physical and mathematical modelling of ignition of small magnesium particles

Abstract

Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.

The distributed mathematical model (nonstationary 1D and 2D) of magnesium particle ignition is developed taking into account the heterogeneous chemical reaction, the domain of particle thermal influence to gas, and the realistic particle temperature after ignition. Solvability of the corresponding mathematical problem in the stationary one-dimensional case in some kinds of symmetry has allowed one to expand classification of regular modes of heating, and also modes of extinction and ignition of a particle. The numerical method for solving the considered class of boundary value problems of magnesium particles ignition is developed, and the mathematical model is verified by the experimental dependences of: ignition delay time on surrounding gas pressure and particle radius; limiting ignition gas temperature on surrounding gas pressure and particle radius. The limiting size of a gas layer near a particle is found that determines an ignition mode in the frame of this realistic mathematical model. The work was supported financially by the Russian Foundation for Basic Research, Grant No 06–01–00299.