Droplet vaporization model for spray combustion calculations

Abstract The re-examination of the classical droplet vaporization model is made in order to develop the simple but sufficiently accurate calculation algorithm which can be used in spray combustion calculations. The new model includes the effects of variable thermophysical properties, non-unitary Lewis number in the gas film, the effect of the Stefan flow on heat and mass transfer between the droplet and the gas, and the effect of internal circulation and transient liquid heating. To evaluate the competing simplified models of the droplet heating, the more-refined, extended model of heat transfer within a moving circulating droplet is considered. A simplified, one-dimensional ‘effective conductivity’ model is formulated for the transient liquid heating with internal circulation. As an illustration, the dynamic and vaporization histories of the droplets injected into the steady and fluctuating hot air streams are analyzed.