Numerical calculations were performed of the gasification and combustion of a liquid fuel droplet which was injected into a quiescent gas at a thermodynamic state far above the critical point of the fuel. Since spatially continuous phase change occurs from the beginning, the droplet is free from surface tension and latent heat of gasification. The calculation was conducted for the two-dimensional version of the problem.
The effect of initial droplet speed emerges through the deformation of droplet shape, yielding different gasification/combustion characteristics from the subcritical case. It is found that, at large Reynolds numbers, the gasification rate is almost invariant with time and the. gasification lifetime shortens inversely proportional to the initial droplet speed. The flame sheet calculation conducted for a small fuel-to-oxygen stoichiometric ratio shows that the gasified fuel is accumulated in a region enclosed by the flame and then burns gradually at a, rate controlled by the diffusion of oxygen in the quiescent ambience. The combustion lifetime is, therefore, independent of initial droplet speed. The underlying physics were also explored.