The effects of particle shape on the thermohydraulic performance of a boehmite nanofluid in a microchannel heat sink (MCHS) with different cross-sections are investigated. This investigation is performed for five nanoparticle shapes (platelet, cylinder, blade, brick, and oblate spheroid) at four Reynolds numbers in the MCHS with four cross-sections (i.e., circular, triangular, hexagonal, and elliptical). The MCHS with triangular microchannels demonstrates the greatest heat transfer coefficient, followed by the MCHSs with elliptical, hexagonal, and circular microchannels, respectively. The best temperature distribution and the lowest thermal resistance are realized for the MCHS with triangular microchannels. Moreover, the MCHS with circular microchannels results in the highest Figure of Merit (FoM), while the MCHS with triangular ones demonstrates the lowest FoM. The nanofluid with platelet particles causes the highest pressure loss, whereas the one with the Os-shaped particles has the lowest pressure loss. For all the nanoparticle shapes and cross-sections, uniformity of temperature distribution (θ) and thermal resistance reduce, while the heat transfer coefficient, pressure drop, and pumping power increase by rising the Reynolds number. Additionally, the colloid with the platelet-shaped particles causes the greatest heat transfer coefficient, pursued by the nanofluids with the cylinder-, blade-, brick-, and Os-shaped particles, respectively.

研究了颗粒形状对具有不同横截面的微通道散热器 (MCHS) 中的勃姆石纳米流体的热工水力性能的影响。本研究针对 MCHS 中具有四个横截面（即圆形、三角形、六边形和椭圆形）的四个雷诺数下的五种纳米颗粒形状（片状、圆柱状、叶片状、砖状和扁球状）进行。具有三角形微通道的 MCHS 表现出最大的传热系数，其次是具有椭圆形、六边形和圆形微通道的 MCHS。具有三角形微通道的 MCHS 实现了最佳的温度分布和最低的热阻。此外，具有圆形微通道的 MCHS 导致最高品质因数 (FoM)，而带有三角形的 MCHS 表现出最低的 FoM。含片状颗粒的纳米流体压力损失最大，而含 Os 形颗粒的纳米流体压力损失最低。对于所有纳米颗粒的形状和横截面，温度分布的均匀性（θ ) 和热阻减小，而传热系数、压降和泵送功率随着雷诺数的增加而增加。此外，具有片状颗粒的胶体产生最大的传热系数，分别由具有圆柱状、叶片状、砖状和 Os 状颗粒的纳米流体所追求。