| Microchannel heat sinks are a relevant thermal management technology because the combination of surface area enhancement and small length scales results in low thermal resistance. Previously, a thermal resistance of 0.09°C/W was achieved when a heat flux of 790 W/cm2 was imposed on a 1 cm x 1 cm footprint portion of a 400 mum-thick Si substrate utilizing single-phase microchannel cooling. Water was driven through the system with a 214 kPa pressure difference. The analysis provided here, which was experimentally validated, predicted that the thermal resistance could be reduced to below 0.07°C/W by refining the microchannel geometry. Such a resistance implies that future generations of electronics, such as microprocessors with an average heat flux of 1000 W/cm2 and even higher ones at "hot spots," could be accommodated by single-phase water cooling.;Galinstan, a gallium, indium and tin eutectic, may be exploited for enhanced cooling of microelectronics due to its sub-ambient melting temperature and high thermal conductivity. Significantly, Galinstan may be pumped using reliable, silent, vibration-free and compact magnetohydrodynamic pumps (without any moving parts) that may be integrated onto printed wiring boards (PWBs) through which it flows. However, a critical evaluation of the cooling potential of Galinstan had not been undertaken prior to this dissertation. Extending the aforementioned analysis to Galinstan-based minichannel heat sinks, it was predicted that lower thermal resistance than possible with water may be achieved.;Experimentally, the thermal resistance previously reported in the literature for water-based microchannel cooling was successfully reproduced for the first time. Moreover, a thermal resistance of 0.071°C/W has been achieved at a heat flux of 1003 W/cm2 with a more rigorously optimized design. In the case of Galinstan, a thermal resistance of 0.077°C/W was achieved at a heat flux of 1214 W/cm2 and heat fluxes as high as 1504 W/cm2were achieved. |
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