Convective droplet vaporization with transient non-convective liquid-phase heating

Abstract

The vaporization of a liquid droplet in a hot convective gaseous environment when the internal liquid-phase motion is completely inhibited has been analyzed. A two-dimensional analysis of the droplet heating is employed in the present model. The liquid-phase heating is solved by an ADI method and is coupled to the gas-phase equations which are solved using an integral approach. The contribution of the wake region has also been included in a simplified manner. Transient mass vaporization rates and transient temperature fields within the droplet have been obtained for n -hexane, n -decane and n -hexadecane, and compared with those of droplet vaporization including liquid-phase circulation. The results indicate that droplet core heating is slow, whereas the rise in the surface temperature is initially fast, but persists throughout. The results further indicate that the droplet life-time is not affected very much by the absence or the presence of liquid-phase convections, although the temperature fields within the droplet are quite different. In the absence of liquid-phase circulation, the lifetime of the n -hexadecane (a less volatile fuel) droplet is reduced by about 10 percent. A one-dimensional model of droplet heating is also proposed.