The combustion of micro dust particles, specially, metal dust particles have the extensive application in different modern technology fields. Therfore, in the first step, a new one-dimensional analytical model for the combustible mixture containing fuel particles (beryllium) uniformly distributed in an oxidizing gas is presneted and the effects of radiation and heat loss as the determing factors on the metal dust combustion are considered and consequently, the burning velocity, quenching distance and low flammability limit are calculated by this novel mathematical approach. It is worth noting that the present model demonstrates the great compatibility with the available models for aluminuum particles. Since all the analytical studies in the field of metal dust combustion are in one-dimensional and the obtained results from these models don’t have the considerable agrrement with the experimental data, in the next part of this research, the structure of laminar, two-dimensional, steadystate, rich and lean mixture of fuel and oxidizing gas is analyzed. It is needed to mention that the results from this two-dimensional model have a remarkable adjustment with the experimental data in contrery to previous one-dimensional models. In the last section of this thesis, firstly, the published model for the droplet combustion is developed in temrs of considering a radiative impact and a modified model is exhibited in comparison with the previous model (Shabi Ulzama) and finally, the gained results from this model are compared with the experimental data which claims that this model has a great agreement with the experimental data. Secondly, a new model for the combustion of coal particles is improved based on the available model for the droplet combustion. Moreover, in this part an attempt has been made to investigate the role of pyrolysis on the coal dust combustion. Key words Combustion, Burning velocity, Quenching distance, Dust particles