Chen Fang, Milnes David, Anita Rogacs, Kenneth Goodson

Frontiers in Heat and Mass Transfer (FHMT) 1 - 013002 (2010)

Vapor-venting microchannel heat exchangers are promising because they address the problems of high pressure drop, flow instability, and local dry-out that are common in conventional two-phase microchannel heat sinks. We present a 3D numerical simulation of the vapor-venting process in a rectangular microchannel bounded on one side by a hydrophobic porous membrane for phase-separation. The simulation is based on the volume of fluid (VOF) method together with models for interphase mass transfer and capillary force. Simulation shows the vapor-venting mechanism can effectively mitigate the vapor accumulation issue, reduce the pressure drop, and suppress the local dry-out in the microchannel. Pressure surge is observed in the vapor-venting channel. The simulation provides some insight into the design and optimization of vapor-venting heat exchangers.