Influence of the Strain Rate, Particle Size, and Equivalence Ratio on the Combustion of the Premixed Air–Aluminum Microparticle Mixture with a Counterflow Structure

Abstract

The effects of the strain rate, equivalence ratio, and particle diameter on the combustion of a mixture of aluminum microparticles with air under fuel-lean conditions are studied in the counterflow configuration with an approximate analytical perturbation method. The flame structure is assumed to consist of three zones: preheating, flame, and post-flame zones. Reasonable agreement between the current results and experimental data is obtained in terms of the flame temperature. The dimensionless ignition and ultimate flame temperatures, place of the flame starting point, and flame thickness are obtained as functions of the strain rate for different particle diameters and equivalent ratios. The results indicate that the ignition and ultimate flame temperatures and also the flame thickness decrease with increasing strain rate. With a decrease in the strain rate, the length of the preheating zone increases. With increasing particle diameter, the flame thickness increases, whereas the ignition and ultimate flame temperatures decrease. An increase in the equivalence ratio causes an increase in the ultimate flame temperature and reduction of the preheating zone and flame thickness.