Diffusion combustion of a liquid fuel film on a metal substrate

Diffusion combustion of a film of a liquid fuel ($n$-undecane and $n$-butanol) deposited on the surface of a thin metal substrate is studied experimentally and theoretically. The experimental data obtained show that the mechanism determining the heating and evaporation of the combustible liquid is the heat transfer from the region of combustion products to the heating zone due to the high longitudinal thermal conductivity of the substrate. Prior to combustion, the combustible liquid may evaporate, not reaching the boiling point. A simple model that takes into account these features is proposed. The calculated velocities of flame propagation and temperature profiles are compared to experimental data. It is shown that the model gives a correct description of the dependence of the flame velocity on the substrate thickness, initial temperature, and properties of the substrate and liquid fuel.