In the present work, combustion of aluminum dust cloud has been studied in media with spatially discrete sources by means of numerical approach. A thermal model has been generated to estimate the flame propagation speed in various oxidizer concentrations. The model is based on conduction and radiation heat transfer mechanisms and using the heat point source method. First combustion of single-particle is studied and the solution is presented. Then the dust combustion is investigated using the superposition principle to include the effects of particles. Oxygen and Nitrogen have been considered as the main oxidizer and the inert gas, respectively. Flame speed as a function of particle diameter has been studied and the effects of radiation heat transfer have been taken to account. Furthermore, Minimum ignition energy as a function of dust concentration for different particle diameters has been investigated. Reasonable agreement between the results of numerical solution of aluminum dust cloud combustion and experimental data is obtained in terms of flame propagation speed and minimum ignition energy.