In this talk, a novel cooling heat sink and system architecture is introduced. The new approach is enabled by a recent breakthrough in phase-change heat transfer science that has resolved fundamental device and system level issues associated with the existing two-phase cooling technologies. The new cooling concept involves boiling heat transfer but in a fundamentally different way than boiling surfaces implemented in the past several decades.
On a typical boiling surface, bubbles crowding at the solid-liquid interface leads to surface dryout. In the new approach, a hydrophobic vapor permeable membrane removes bubbles from the surface. This bubble removal action facilitates surface rewetting and results in an order of magnitude increase in the dryout heat flux (1,800 W/cm 2 with water).
The proposed approach addresses a fundamental issue that prevents implementation of two-phase cooling in systems with multiple heat sources. When multiple conventional heat sinks are connected to a single liquid line, since two-phase flow pressure drop is a strong function of vapor quality, flow is diverted from heat sinks with a high heat load to ones with little or no heat load.
In contrast, the new approach enables building thermal management platforms involving numerous heat sinks connected to a single liquid supply line. Heat sinks can operate at varying heat load without interfering with each other performance. Their exit vapor quality remains at 100% regardless of the heat sink input. A system built based on the new concept enables flow auto-regulation between heat sinks with vastly different heat loads.