The Effects of Nozzle Configuration and Coolant Flow Rate on Spray Evaporative Cooling in a Multi-Chip Module Using FC-72

With the power levels of computers constantly rising, the cooling of the die is becoming more challenging. One method of heat removal that can handle high heat fluxes and is still compact in size is Spray Evaporative Cooling (SEC). SEC, in this instance, uses arrays of nozzles to deliver a fluorinert cooling fluid, FC-72, to the die surface, and in the right conditions, a thin liquid film will form. This thin film allows for very high heat removal. Saturating the FC-72 with nitrogen enhances the effect. The characteristics of the spray greatly affect the behavior of the film. The critical heat flux (CHF), heat transfer coefficient of the system, and the variation in temperature on the die surface are important characteristics of an SEC system that must be considered. This study presents results of experiments performed to determine the effect of the number of spray nozzles on these quantities.