不同直径和流量对层叠式微通道散热器热性能的影响研究
Effects of Diameters and Flow Rates on Thermal Performance of Multi-Layered Microchannel Heat Sink

本文基于PCHE板提出层叠式微通道散热器，并对其在不同直径和流量下进行了数值模拟分析。结论表明，增大流量可以增强散热器换热性能，当散热器一个分析单元的流量从20 ml/min增至40 ml/min时，热阻可降低约35%，但随着流量的进一步升高热阻的减小率也会逐渐下降。流量保持一定时减小通道直径也可以达到增强换热的效果，但增大流量以及减小通道直径都会引起压降的增加。层叠式微通道散热器各层通道的换热情况不相同，底层流体在入口处附近换热较强，而高层部分的流体在入口处换热很弱。在充分发展段，各层通道流体与壁面换热的Nu数趋于一致。
In this work, a multi-layered microchannel heat sink is proposed based on PCHEs, and the numerical simulation analysis is carried out under different diameters and volume flow rates. Increasing the flow rate can enhance the heat transfer performance of the heat sink. When the flow rate increases from 20 ml/min to 40 ml/min, the thermal resistance can be reduced by 35%, but as the flow rate further increases, the reduction rate of thermal resistance will gradually decrease. And when the volume flow rate remains constant, reducing the channel diameter can also achieve the effect of enhancing heat transfer, but both increasing the flow rate and reducing the channel diameter will increase the pressure drop. The heat transfer conditions of each layer of the multi-layered microchannel heat sink are different. The heat transfer of the bottom fluid is strong near the inlet, while the heat transfer of the fluid in the upper layer is weak at the inlet. In the fully developed region, the Nusselt number of the heat transfer between the fluid and the channel wall in each layer tends to be consistent.