SCALABLE LARGE-AREA TWO-PHASE CAPILLARY-ENHANCED MICRO-COOLER USING SILICON MICROCHANNEL FIN ARRAY WITH 3D SILICON MANIFOLD FOR HIGH-HEAT-FLUX ELECTRONICS COOLING APPLICATION

초록

We have developed a silicon-based capillary-enhanced two-phase micro-cooler capable of removing a high heat flux > 200 Wcm(-2) with water mass flow rate approximate to 28 g(min)(-1) (vapor quality, x(e) approximate to 0.8) over a large area approximate to 2 cm x 2 cm at superheat < 20 degrees C, resulting in a thermal resistance of phase change, R-mean,R-2-phi '' approximate to 0.08 cm(2)degrees CW-1. By increasing the flow rate to approximate to 150 g(min)(-1), a hybrid single/two phase regime prevails resulting in a critical heat flux approximate to 285 Wcm(-2) (1.1 kW/chip) with minimal pressure drop approximate to 10 kPa, achieving 100x larger Coefficient of Performance (COP), compared to the conventional forced convective microchannel cooling. In this work, we utilize dense silicon channel fin array (height 100 mu m, width 15 mu m and 15 mu m spacing) as capillary wicking structure in combination with a 3D silicon open-microchannel manifold (channel width and period approximate to 100 mu m and 570 mu m, respectively) for capillary-based liquid delivery and vapor extraction over large, heated area of 2 cm x 2 cm. The micro-cooler performs the best at low flow rates and high heat fluxes where the capillary flow and two-phase boiling dominates, resulting in a very uniform temperature distribution over the large area of the micro-cooler. At the high flow rates (pressurized flow), the coolant bursts out of the gap between the 3D manifold and the cold plate, resulting in single-phase cooling near the inlets of the micro-cooler. The temperature profile and its uniformity, or lack thereof, strongly depend on the competing effects of the single-phase and two-phase cooling regimes, which in turn depend on the flow rate and applied heat flux.

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