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.%为强化微通道热沉的传热性能,设计一种内置微柱体的微通道热沉,并采用数值方法研究微柱体对微通道热沉内流体流动、传热及综合性能的影响.分析了进口雷诺数、微柱体的错位量对内置微柱体微通道热沉(微柱通道)的压降、热阻和努塞尔数的影响,并与光滑微通道热沉(光滑通道)进行对比.采用热阻与泵功的关系、熵产原则及性能评价准则对微通道热沉的综合性能进行评价.结果表明,微柱通道压降和努塞尔数随雷诺数增大而增大,热阻反而减小;在研究的雷诺数范围内,微柱通道压降比光滑通道的平均高84.3％,热阻平均低27.8％,而努塞尔数平均高54.5％;有错位量的微柱通道热阻比无错位量的平均低8.9％,而努塞尔数平均高12.6％;微柱通道综合性能优于光滑通道,且有错位量的微柱通道更优.
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