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Effects of micro-cylinders on overall performance of micro-channel heat sinks:numerical simulation |
FENG Zhenfei1,2, LUO Xiaoping1, GUO Feng1, LI Haiyan1, WANG Zhaotao1
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(1.School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510641, China;2.Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, Guangxi University, Nanning 530004, China)
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Abstract: |
In order to enhance the heat transfer performance of micro-channel heat sinks, a micro-channel heat sink with micro-cylinders is presented and the effects of micro-cylinders on the fluid flow, heat transfer and overall performance in the micro-channel heat sinks are studied numerically. The effects of the inlet Reynolds number and micro-cylinder offset value on the pressure drop, thermal resistance and Nusselt number are analyzed, and these results are compared with those of the plain micro-channel heat sink. Then the overall performance on the micro-channel heat sink is evaluated by using the thermal resistance-pumping power relation, entropy generation principle and performance evaluation criterion. It is found that the pressure drop and Nusselt number increase and the thermal resistance decreases with the increase of the Reynolds number. For the studied Reynolds number range, there are the 84.3% average increase in the pressure drop, a 27.8% average decrease in the thermal resistance and a 54.5% average increase in the Nusselt number for the micro-channel heat sink with micro-cylinders, in comparison with the plain micro-channel heat sink. There are a 8.9% average decrease in the thermal resistance and a 12.6% average increase in the Nusselt number for micro-channel heat sinks with the micro-cylinder offset value being nonzero, compared with that with the micro-cylinder offset value being zero. The overall performance in the micro-channel with micro-cylinders is much better than that of the plain micro-channel. Furthermore, the overall performance in the micro-channel with micro-cylinder offset value being nonzero is much better. |
Key words: micro-channel micro-cylinder numerical simulation flow heat transfer |
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