A 3D numerical simulation is carried out to investigate thermal and hydraulic characteristics of the straight, wavy, and combined minichannel heat sinks (MCHSs) with both co- and counter-current patterns. An aspect ratio with a hydraulic diameter of 1 mm is adopted for all models. The coolant is water under laminar flow regime (Re = 100 – 900), and the input heat flux is 100 kW/m². First, the employed procedure and obtained results are verified by using the current experimental results and previous data reported by literature. Then, a detailed analysis is performed to find the profit and performance boost of the counter-current pattern compared to the co-current pattern. The results show that replacing the co-current pattern with the counter-current pattern can significantly reduce the maximum temperature difference at the base of MCHSs, leading to more uniform temperature. This reduction can reach up to about 18.5 K at Re = 100. The important point is that the effect of changing the flow pattern in the straight MCHS is greater than the other ones. However, all enhanced MCHSs (wavy and combined) illustrate better overall performances compared to the straight one. A continuous enhancement is observed in the overall performance index with increasing Reynolds number, and the maximum value of 2.22 is found at Re = 900 for the wavy MCHS with counter-current pattern. Finally, a comparative study is carried out, and it found that a change in the flow pattern can work better than many structural modifications in wavy MCHSs.

进行 3D 数值模拟以研究具有并流和逆流模式的直、波浪和组合微通道散热器 (MCHS) 的热和水力特性。所有型号均采用水力直径为1mm的纵横比。层流状态下冷却剂为水（Re  = 100 – 900），输入热通量为100 kW/m ². 首先，通过使用当前的实验结果和文献报道的先前数据来验证所采用的程序和获得的结果。然后，进行详细分析以找出逆流模式与并流模式相比的利润和性能提升。结果表明，用逆流模式代替并流模式可以显着降低MCHS底部的最大温差，从而使温度更加均匀。这种减少在Re 下可以达到约 18.5 K = 100。重要的一点是在直的 MCHS 中改变流型的影响比其他的要大。然而，与直线型相比，所有增强型 MCHS（波浪型和组合型）都表现出更好的整体性能。随着雷诺数的增加，在整体性能指标中观察到持续增强， 对于具有逆流模式的波浪形 MCHS，在Re = 900处发现最大值 2.22 。最后，进行了比较研究，发现流动模式的变化比波浪 MCHS 中的许多结构修改效果更好。