Droplet Cooling Heat Transfer Model Validation 2000-01-3644
Heat transfer by phase change is an attractive method of cooling since large amounts of heat can be removed with relatively small temperature differences. Droplet cooling is one method whereby very high heat transfer rates coupled with good temperature uniformity across surfaces can be provided, which is important in microelectronics where even small temperature gradients across the chip can cause component failure. When a droplet strikes a heated surface, it flattens into a splat whose thickness is much smaller than the diameter of the droplet, and high heat fluxes can be obtained due to the formation and evaporation of a thin liquid film on the heated surface. In this study, time and space resolved heat transfer characteristics for a single droplet striking a heated surface were experimentally measured, and the results are compared to a model of droplet evaporation. The results confirm that the main resistance to heat transfer over the majority of the droplet evaporation time is caused by the vapor leaving the surface - the thermal resistance of the liquid was small. Good agreement was obtained between the model and experiment.