Porous Media Modeling of Two Phase Microchannel Cooling of Electronic Chips With Nonuniform Power Distribution

Abstract

Compared to singlephase heat transfer, twophase microchannel heat sinks utilize latent heat to reduce the needed flow rate and to maintain a rather uniform temperature close to the boiling temperature. The challenge in the application of cooling for electronic chips is the necessity of modeling a large number of microchannels using large number of meshes and extensive computation time. In the present study, a modified porous media method modeling of twophase flow in microchannels is performed. Compared with conjugate method, which considers individual channels and walls, it saves computation effort and provides a more convenient means to perform optimization of channel geometry. The porous media simulation is applied to a real chip. The channels of high heat load will have higher qualities, larger flow resistances, and lower flow rates. At a constant available pressure drop over the channels, the low heat load channels show much higher mass flow rates than needed. To avoid this flow maldistribution, the channel widths on a chip are adjusted to ensure that the exit qualities and mass flow rate of channels are more uniform. As a result, the total flow rate on the chip is drastically reduced, and the temperature gradient is also minimized. However, it only gives a relatively small reduction on the maximum surface temperature of chip.