Cooling and solidification of liquid-metal drops in a gaseous atmosphere

Abstract

The free fall of a liquid-metal drop, heat transfer from the drop to its environment, and solidification of the drop are described for both gaseous and vacuum atmospheres. A simple model, in which the drop is assumed to fall rectilinearly, with behaviour like that of a rigid particle, is developed to describe cooling behaviour. Recalescence of supercooled drops is assumed to occur instantaneously when a specified temperature is passed. The effects of solidification and experimental parameters on drop cooling are calculated and discussed. Major results include temperature as a function of time, and of drag, time to complete solidification, and drag as a function of'the fraction of the drop solidified.

Modeling of solidification of molten metal droplet during atomization

“…The results show in Figure 8 are similar to those shown in the existing literature. [18] Prior to nucleation or recalescence, a small droplet has a lower temperature at a given flight distance than a large droplet has, because the smaller the droplet, the better the cooling effect by the atomization gas. In addition, the small droplet has a lower nucleation temperature than the large droplet, since the small droplet encounters a faster cooling rate, which lowers the nucleation temperature, as shown in Figure 9.…”

“…[15][16][17][18][19] However, during atomization, the cooling rate, and thus the solidification rate, of the molten metal droplets is very high, which gives very little time for the nucleation event to happen. In the present work, the concept of transient nucleation, [20] instead of the steady-state nucleation, is considered to model such short nucleation events during solidification of the atomized droplets.…”