Optimization of heat sinks with plate fins in air-jet cooling

Abstract

Heat density of high-load electronics such as high-performance servers and the inverters used in vehicles has been increasing as the result of higher processing speeds and computational scale, and higher output, etc. We therefore investigated an air-jet cooling structure that uses a plate-fin heat sink with the objective of developing an air-cooling structure that can provide efficient, uniform cooling for high-density mounting configurations in high-load electronics. The plate-fin heat sink mounted on a semiconductor package was cooled by an air jet injected from a rectangular nozzle mounted on top of the heat sink. The heat sink shapes and nozzle width, as well as the blower power, were changed to investigate the effect on heat transfer. This allowed the optimal parameters to be found for the nozzle width, the fin spacing, and the fin height of the heat sink, thereby resulting in a maximum heat transfer coefficient. Also, the flow pattern in the heat sink was visualized qualitatively. The results show the heat transfer coefficient of the air jet cooling is larger than that of parallel flow cooling under constant blower power consumption. And it takes maximum values with H/Wf= 0.35-0.4, which is unique phenomenon to an air jet cooling and is not seen in parallel flow cooling.

Keywords

• heat transfer
• forced convection
• jet
• cooling
• heat sink
• fin
• pressure drop
• visualization
• large scale computing system