Ultra-high heat flux dissipation with Piranha Pin Fins

Experiments were conducted to study the effects of micro-pin-fins and submicron-scale roughness on the boiling heat transfer from a silicon chip immersed in a pool of degassed and gas-dissolved FC-72. Square pin-fins with fin dimensions of 50×50×60μm3 (width×thickness×height) and submicron-scale roughness (RMS roughness of 25 to 32 nm) were fabricated on the surface of square silicon chip 10×10×0.5mm3 by use of microelectronic fabrication techniques. Experiments were conducted at the liquid subcoolings of 0, 3, 25, and 45 K. Both the micro-pin-finned chip and the chip with submicron-scale roughness showed a considerable heat transfer enhancement as compared to a smooth chip in the nucleate boiling region. The chip with submicron-scale roughness showed a higher heat transfer performance than the micro-pin-finned chip in the low-heat-flux region. The micro-pin-finned chip showed a steep increase in the heat flux with increasing wall superheat. This chip showed a higher heat transfer performance than the chip with submicron-scale roughness in the high-heat-flux region. The micro-pin-finned chip with submicron-scale roughness on it showed the highest heat transfer performance in the high-heat-flux region. While the wall superheat at boiling incipience was strongly dependent on the dissolved gas content, it was little affected by the liquid subcooling.

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Liquid Cooling Utilizing a Hybrid Microchannel/Multi-Jet Heat Sink: A Component Level Study of Commercial Product

ASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems ◽

10.1115/ipack2020-2627 ◽

2020 ◽

Author(s):

Cong Hiep Hoang ◽

Mohammad Tradat ◽

Yaman Manaserh ◽

Bharath Ramakrisnan ◽

Srikanth Rangarajan ◽

...

Keyword(s):

Heat Flux ◽

Flow Rate ◽

Heat Sink ◽

High Heat ◽

Inlet Temperature ◽

High Heat Flux ◽

Micro Channel ◽

Water Coolant ◽

Liquid Cooling ◽

Pin Fins

Abstract The miniaturization of microelectronic devices and an increasing demand for faster computing results in high heat flux applications. By adopting direct liquid cooling, the high heat flux and high-power demands can be met. In this paper, thermo-hydraulic performance of a commercial hybrid micro-channel/multi-jet heat sink with water coolant was analyzed in detail. The copper microchannel heat sink with 3 mm fin height, fin thickness of 0.1 mm and channel width of 0.1 mm was used for removing heat flux from the chip surface area of 1″ × 1″(6.45 cm2). Water coolant was directed to microchannel fins by multiple slot jets, continuously providing impingement flow. A three-dimensional numerical simulation using commercial software 6sigmaET is carried out and validated with experimental results. The effects of the coolant inlet temperature and flow rate on the thermo-hydraulic performance was studied. CFD simulation was performed at inlet temperature of 29 °C, 36 °C, 50 °C and 60 °C. Flow rate was varied from 0.7 LPM to 3 LPM. Geometry optimization was performed, considering process of cutting the microchannel into pin fins. It was observed that the thermal resistance of pin-fins/multi-jet heat sink was reduced by 29.4 % as compared to original microchannel/multi-jet heat sink and without changing pressure drop significantly. In this specific heat sink design, the combination of multiple jets and pin fins leads to improvement of thermal performance as compared to micro-channel/multi-jet combination.

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