UNDERCOOLING AND CONTACT RESISTANCE IN STAGNATION-FLOW SOLIDIFICATIONON A SEMIINFINITE SUBSTRATE

The inviscid stagnation-flow solidification problem in studied numeric ally including the effect of contact resistance and undercooling durin g solidification. The effect of contact resistance at the initial liqu id-solid contact plane is demonstrated by comparing the solidification behavior for cases with different contact heat transfer coefficient. The effect of undercooling is examined by comparing model predictions including this effect with those obtained when equilibrium solidificat ion with interface temperature at the thermodynamic equilibrium temper ature is used. The study shows that undercooling delays the start of s olidification but has a negligible effect on the long time behavior of the process. A sufficiently large contact resistance may prevent soli dification when undercooling is included in the model. (C) 1998 Elsevi er Science Ltd. All rights reserved.