New attempt of forced-air cooling for high heat-flux applications

The electronic industry requires increased forced-air cooling limits in order to adequately cool high-end server CPU and also the power electronic IGBT. Improving the air-cooled heat sink thermal performance is one of the critical areas for increasing the overall air-cooling limit. One of the challenging aspects for improving the heat sink performance is utilizing relatively large air-cooled fin surface areas when heat is being transferred from a relatively small heat source (CPU) with high heat flux. Similar to heat pipe technology, the pulsating (or oscillating) heat pipe utilizes two-phase flow to transfer heat from the CPU. However, unlike heat pipe technology, the pulsating heat pipe does not contain wicking structure. This study shows that the pulsating heat pipe (Heatlane technology) enables the high-end server CPU power to be efficiently spread to the heat sink fin structure. Measured results show that the Heatlane heat sink will yield sink-to-air thermal impedances that are less than the measured impedance for conventional (all-metal) heat sink design.