Numerical studies on laminar diffusion flames over methanol pool surface in opposed air-flow configuration

Studies on opposed flow diffusion flame over a liquid-fuel surface provides fundamental understanding of the structure of the flame and its extinction characteristics. Such studies also aid in the development of chemical kinetics mechanism for that fuel. Various factors such as air velocity flowing perpendicularly on the top of the fuel surface, separation distance between fuel surface and air nozzle exit and mass fraction of oxidizer in air, influence the flame structure. This paper presents a parametric study to elucidate the effect of opposed flow air velocity on flame structure formed over the methanol pool and its mass burning rate. The numerical simulations are carried out using a well validated model, capable of simulating diffusion flames over condensed fuel surfaces under various environmental conditions. Two different configurations are considered; in the first, without horizontal top and bottom walls (unconfined) and in the second, with adiabatic horizontal walls kept in flush with pool surface and nozzle exit plane to create a confining environment. A comparison of flame shapes and burning rates from these two cases are presented and discussed in detail.