FLOW STRUCTURES AND HEAT-TRANSFER IN A LID-DRIVEN CAVITY FILLED WITH LIQUID GALLIUM AND HEATED FROM BELOW

Experiments and three-dimensional unsteady numerical simulations have been performed to investigate natural and mixed convection in a shallo w rectangular cavity filled with liquid gallium. The cavity was heated from below and cooled from above either in the absence or presence of lid motion. Experiments were conducted in a cavity having aspect rati os of 10 and 5 in the longitudinal and spanwise directions, respective ly. Temperatures were recorded at different locations in the cavity, a nd temporal variation of the temperatures were analyzed using a fast F ourier transform. Three-dimensional unsteady direct numerical simulati ons were performed to obtain improved understanding of the flow struct ure in the cavity. The results show that lid motion has a significant effect on the flow and thermal structures in the cavity. For Richardso n numbers less than unity, the effect of the lid motion is to reorgani ze the flow and to make the flow structure quasi-two-dimensional.