Experimental Study on Heat Transfer Enhancement of Natural Circulation Liquid Cooling System for Electronic Component

The present research is an experimental study on heat transfer characteristics of a natural circulation cooling system for electronic components. A smooth chip and two micro-pin-finned chips were tested. The chip is mounted on the base of a rectangular horizontal duct located at the bottom of 250 mm high natural circulation loop.FC-72 is used as a coolant. The test conditions are set that the operation pressure of experimental system is 1. 013× 105 Pa, the flow rate of FC-72 is 150 g/min and the subcoolings are 10 K, 25 K and 35 k, respectively. Effect of the subcooling on nucleate boiling and critical heat flux(CHF) were investigated. The results show that subcoolingis found to significantly affect CHF for all chips and micro-pin-finned chips sharply enhanced the boiling heat transfer, CHF of micro-pin-finned chips are 2.5～3 times as large as that of smooth chip at the same subcooling.

An investigation on topologies of hybrid manifold,impinging-jet nozzle and micro-pin-fin heat sinks

The hybrid manifold micro-pin-fin(MMPF)heat sink combined nozzle jets is an option for large-scale integrated circuits(LSI).The demond for uniform and ultra-high heat flux removal by MMPF heat sink has not been adequately investigated.This work aims to solve the problem of fluid organization.The proposed basic tiling topologies,including square,regular hexagon,30°rhombus,and 60°rhombus topologies,provide different organized fluid flows and heat transfer patterns.The present study focuses on comparing these topologies according to independent porous medium parameters,such as nozzle pore size D_(Z),flow pore size D_(X,Y),and porosityε.The results show that the square topology achieves the smallest total thermal resistance R_(tot)value of0.0975×10^(-4)K m^2/W,while the hexagon topology achieved the highest value of COP/?T,which was 2033.9 K^(-1).According to the sensitivity analysis results,the optimal total thermal resistance can be obtained by balancing the influences of nozzle pore size,flow pore size,and porosity.The optimal pressure drop can be obtained by maximizing the porosity.

An investigation on application potentiality of microstructure heat sinks with different flow topological morphology

Microstructure heat sinks have great potential for high heat flux cooling.In this paper,we compared microchannel(MC),micro-pin-fin(MPF),manifold microchannel(MMC),and manifold micro-pin-fin(MMPF)heat sinks to figure out the pros and cons.Fluid flow and manifold unit models are used to study thermal and hydrodynamic performance.The heat sinks with different channel/fin sizes,manifold numbers,and porosities are discussed according to the pressure drop,temperature,thermal resistance,and coefficient of performance.Results show that MMC and MMPF heat sinks are superior to MC and MPF heat sinks,and there are also differences between MMC and MMPF heat sinks.Typically,the MMPF heat sink has lower maximum temperature,temperature non-uniformity,and total thermal resistance R_(tot).In contrast,the MMC heat sink has a lower pressure drop and higher COP.For the MMPF heat sink,at the nozzle width of 6.75μm and the MPF width of 70.71μm(porosity=0.167),it achieves the lowest total thermal resistance of R_(tot)=2.97×10^(-6)K m^(2)/W.Under 10^(3)W/cm^(2)heat flux,the maximum surface temperature rise is 29.74 K,and the maximum temperature difference of the heating surface is 3.15 K.This research initially provides a clear reference on the selection of single-phase cooling microstructures for ultra-high heat flux dissipation.