Abstract Combining porous layer paved on the side wall and microencapsulated phase change material (MPCM) slurry as working fluid is presented in microchannel heat sink (MCHS), in which more surface area of channel matrix and larger temperature difference between coolant and heating surface during phase change will enhance heat transfer. The Brinkman-Forchheimer extended Darcy model together with energy equation in local thermal equilibrium account for heat transfer and flow in the porous layer as well as the equivalent heat capacity method for phase change of microcapsules under laminar flow. The effects of the materials of porous layer and substrate, heat sink design involving the porosity, thickness and height of porous layer as well as channel number under various inlet velocities and mass fractions of MPCM slurry on the thermo-hydraulic performance, which is evaluated with performance evaluation factor (PEF), in the porous-wall MCHS of MPCM slurry as coolant are analyzed in comparison to the non-porous mode with water passing through, and the 32.3% rise of performance evaluation factor can be obtained. The simulation results are validated with the experimental data. The lower thermal resistance occurs in the porous-wall mode of MPCM slurry as coolant with higher and thicker porous layer of higher porosity and thermal conductivity material as well as proper microchannel number in heat sink under higher inlet velocity than that in the non-porous MCHS with water flowing through, which is closely related to the phase change of MPCM in slurry, and influences PEF in consideration of flowing resistance. The MPCM mass fraction in coolant needs to be properly to avoid larger convection reduction and rise of flowing resistance, so as to obtain the better thermal and hydrodynamic performance of larger PEF.

中文翻译：

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微胶囊相变浆料多孔壁微通道的热工水力特性分析

摘要 微通道热沉(MCHS)采用侧壁铺砌的多孔层和微囊化相变材料(MPCM)浆液作为工作流体，在相变过程中，通道基体的表面积更大，冷却剂与加热表面的温差更大。变化将增强传热。Brinkman-Forchheimer 扩展达西模型与局部热平衡中的能量方程一起解释了多孔层中的传热和流动，以及层流下微胶囊相变的等效热容方法。多孔层和基板材料的影响，涉及孔隙率的散热器设计，不同入口速度和质量分数下的多孔层厚度和高度以及通道数对 MPCM 浆料多孔壁 MCHS 中的热工水力性能的影响，该性能用性能评估因子 (PEF) 进行评估与通水的无孔模式进行对比分析，可得到性能评价系数提升32.3%。仿真结果与实验数据相验证。MPCM浆料的多孔壁模式作为冷却剂，具有更高和更厚的孔隙率和导热率材料的多孔层以及在比无孔MCHS更高的入口速度下散热器中适当的微通道数，出现较低的热阻有水流过，这与浆料中 MPCM 的相变密切相关，并考虑流动阻力影响 PEF。冷却液中的 MPCM 质量分数需要适当，以避免较大的对流减少和流动阻力的增加，从而获得较大 PEF 更好的热和流体动力性能。