Abstract In the present experimental work, forced convective flow boiling heat transfer under subcooled region was analysed with Al2O3/water nanofluid flow in a horizontal tube. Nanofluids at various wt.% such as 0.01%, 0.05%, 0.1%, 0.5% and 1% were prepared using two-step method. Stability of nanofluids was measured using Zeta potential analysis. Thermo-physical properties such as the thermal conductivity and viscosity of all test samples were estimated over 25°C-65 °C. An experimental test rig was setup to study the convective heat transfer using nanofluids. The effects of concentration, heat flux, flow rate, surface roughness on heat transfer coefficient were measured. The experimental result showed good stability in nanofluids without any surfactants. A significant increase in convective heat transfer coefficient (HTC) was found due to enhancement in the thermo-physical properties of nanofluids. Increase in pressure drop was registered with the rise of concentration and flow rate. Finally, performance evaluation criterion (PEC) showed that Al2O3 nanofluids can increase the overall thermal performance of the system by 94% in comparison with pure water.

中文翻译：

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Al2O3/水纳米流体在水平管中的热物理特性和过冷流沸腾性能的实验研究

摘要 在目前的实验工作中，用水平管中的Al2O3/水纳米流体流动分析了过冷区域下的强制对流沸腾传热。使用两步法制备了不同重量百分比的纳米流体，例如 0.01%、0.05%、0.1%、0.5% 和 1%。使用 Zeta 电位分析测量纳米流体的稳定性。在 25°C-65°C 范围内估算了所有测试样品的热物理特性，例如热导率和粘度。设置了一个实验测试台来研究使用纳米流体的对流传热。测量了浓度、热通量、流速、表面粗糙度对传热系数的影响。实验结果表明在没有任何表面活性剂的纳米流体中具有良好的稳定性。由于纳米流体的热物理性质的增强，发现对流热传递系数 (HTC) 显着增加。压降随着浓度和流速的增加而增加。最后，性能评估标准（PEC）表明，与纯水相比，Al2O3 纳米流体可以将系统的整体热性能提高 94%。