The flame structure of submicron-sized aluminum dust particles and air is investigated through a two-phase mixture in a counterflow configuration. A mathematical model is developed to estimate the premixed dust flame location and velocity in terms of the strain rate. In order to simulate combustion of dust particles, a three-zone flame structure is considered, including the preheat, reaction, and post-flame zones. The governing conservation equations for each zone are derived and solved under appropriate boundary conditions. The effects of thermophoresis and Brownian motion of fuel particles are investigated. Moreover, the particle size and polydispersity impacts on the burning rate and flame position are taken into consideration. In general, the simulation results for the flame velocity are in reasonable agreement with the experimental data available in the literature.