Micro channels are widely used in different industries. The investgations on heat transfer improvments of these instruments are of significant inportance. At hte present study, the influence of different nano-fluids and geometrical charectrestics on the thermal performance of a heat sink which is especially for for micro-channels are investigated. In the present study, the authors investigated the Nusselt number and pressure drop in differential geometries and Reynolds numbers (Re). Then the micro-channel was investigated with different heat flux (q).In the first step, the micro-channel was examined and the final numerical results showed that the hexagonal cross-section can improve heat transfer about 9%. At the second step and after selecting appropriate parameters, the effect of three nano-particles (Al2O3 - CuO- TiO2) were studied. The results presented that aluminum oxide (Al2O3) has the best heat transfer rate among the mentioned nano-fluids. With the presence of nano-particles (Al2O3, φ = 4%) an increment of 40% in heat transfer rate, for the hexagonal cross section was achieved compare to rectangular cross section with water as working fluid.

中文翻译：

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纳米流体类型对正六边形微通道传热改善的影响

微信广泛应用于不同行业。对这些仪器的传热改进的投资具有重要意义。在目前的研究中，研究了不同纳米流体和几何特性对散热器热性能的影响，特别是用于微通道。在本研究中，作者研究了微分几何和雷诺数 (Re) 中的努塞尔数和压降。然后用不同的热通量（q）研究微通道。在第一步中，对微通道进行了研究，最终的数值结果表明，六边形截面可以提高约 9% 的传热。第二步，在选择合适的参数后，研究了三种纳米颗粒（Al2O3-CuO-TiO2）的影响。结果表明，在上述纳米流体中，氧化铝 (Al2O3) 具有最佳的传热率。随着纳米颗粒 (Al2O3, φ = 4%) 的存在，传热率增加了 40%，与以水为工作流体的矩形截面相比，六边形截面实现了。