A review and detailed derivation of basic relations describing the burning of droplets

The combustion of a heterogeneous mixture of fuel and oxidizer has been a favored subject for theoretical and experimental studies over the past decades. A number of detailed reviews on the mechanism of combustion of droplets have been carried out. It is the purpose of this paper instead to provide a review and detailed derivation of the basic physical and chemical relations needed to describe the burning of droplets. The emphasis is on the analytical formulation of governing relations, the procedures used to solve these interrelated equations, the application of the proper boundary conditions, and the complete step by step assumptions made along the way. The theme of these discussions show how the simplified Quasi Steady (Q-S) Formulation is eventually attained. The Q-S formulation is generally the theoretical description used in all but a very few of the past studies on droplet combustion. This review also attempts to complement the classic critique by Williams in 1960, which detailed the correctness of the assumptions underlying droplet vaporization combustion theories.