You Xiangcheng
State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China.
Nanomaterials (Basel). 2022 Jul 25;12(15):2552. doi: 10.3390/nano12152552.
With the porous medium-filling inclined channels, we investigate the nanoparticle sphericity of Cu-AlO-HO hybrid nanofluid flows. We consider the constant flow rate through the channels as well as the uniform heat flux on wall channels. We provide analytical solutions for both the velocity and temperature fields. Several parameters are considered in the analytical solutions, including the mixed convection variable, the Peclet number, the channel tilt angle, and nanoparticle sphericity and volume fractions. The significant findings of this study are that the effective thermal conductivity increases when increasing the temperature in the same nanoparticle volume fractions. Nanoparticles with a smaller average sphericity size have a greater specific surface area and contain a greater concentration of small particles, which enhances the internal heat transfer of nanofluids. The other noteworthy observation of this study is that when the nanoparticle volume fraction increases from 0.1 to 0.2, although the heat transfer enhancement rate has slowed down, it has also increased by about 25%. The hybrid nanofluids have suitable stability, and the enhanced heat transfer effect is better with the increase in nanoparticle compositions.
对于填充有多孔介质的倾斜通道，我们研究了Cu - Al₂O₃ - H₂O混合纳米流体流动中的纳米颗粒球形度。我们考虑了通过通道的恒定流速以及壁面通道上的均匀热流。我们给出了速度场和温度场的解析解。解析解中考虑了几个参数，包括混合对流变量、佩克莱数、通道倾斜角以及纳米颗粒球形度和体积分数。本研究的重要发现是，在相同纳米颗粒体积分数下，有效热导率随温度升高而增加。平均球形度尺寸较小的纳米颗粒具有更大的比表面积，并且包含更高浓度的小颗粒，这增强了纳米流体的内部传热。本研究的另一个值得注意的观察结果是，当纳米颗粒体积分数从0.1增加到0.2时，尽管传热增强率有所减缓，但仍增加了约25%。混合纳米流体具有合适的稳定性，并且随着纳米颗粒成分的增加，增强的传热效果更好。
