Abstract The minichannel heatsink is one of the small heat exchangers, having high heat capacity and being able to remove substantial heat within a very small volume, in line with the current demand for heat dissipation of electronic components. In the present study, the convection cooling characteristics in a rectangular minichannel considering wall conduction effect was investigated numerically. Numerical simulations are performed under 2% and 10% volume fractions of PCM particles (n-eicosan). The results reveal that the axial wall conduction plays a more pivotal role in the minichannels at the lower Reynolds number. Besides, the employment of phase change nano-emulsion in the working fluid in the rectangular minichannel suppresses the wall temperature and improves the heat transfer performance up to 4.23% and 9.36%, respectively, compared with the application of pure water. In addition, it is demonstrated that a high concentration of PCM particles may have detrimental effect on pressure drop and extended wall heat dissipation efficiency under certain circumstances thus the concentration of PCM particles needs careful selection.

中文翻译：

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相变纳米乳液在具有壁传导效应的矩形微通道中的热性能

摘要 微通道散热器是小型换热器中的一种，具有较高的热容量，能够在很小的体积内带走大量热量，符合当前电子元器件散热的需求。在本研究中，对考虑壁面传导效应的矩形微通道中的对流冷却特性进行了数值研究。数值模拟是在 2% 和 10% 体积分数的 PCM 颗粒（正二十聚糖）下进行的。结果表明，轴向壁传导在雷诺数较低的微通道中起着更关键的作用。此外，在矩形微通道工作流体中采用相变纳米乳液抑制壁温，传热性能分别提高4.23%和9.36%，与纯水的应用相比。此外，研究表明，在某些情况下，高浓度的 PCM 颗粒可能会对压降和扩展壁散热效率产生不利影响，因此需要仔细选择 PCM 颗粒的浓度。