Thermal performance of Al₂O₃ nanoparticles dispersed in water was evaluated experimentally in a fully instrumented circular tube under turbulent flow conditions. Thermophysical properties of Al₂O₃ nanofluids at three different volumetric concentrations (0.38%, 0.81%, and 1.30%) were determined as a function of temperature. Pressure drop and heat transfer experiments were carried out at different volumetric concentrations and inlet fluid temperatures (10°C–30°C). The overall performance of the Al₂O₃ nanofluids was evaluated by considering both their hydraulic and heat transfer characteristics. The experimental results showed that the use of Al₂O₃ nanofluids increases the pressure drop by up to about 13% due to the greater viscosity. In addition, the heat transfer coefficient of nanofluids increased with the volumetric concentration by up to approximately 19% induced by the enhanced thermal conductivity. Furthermore, the experimental results indicated that the nanofluid with a volume fraction of 0.81% at the highest inlet fluid temperature increases the overall performance by up to around 8% and performs better than the other volume fractions. Enhancement in the overall performance increases with increasing inlet fluid temperature because of both the enhanced effective thermal conductivity and the decreased viscosity, which increases the energy exchange and decreases the pressure loss, respectively.

在湍流条件下，在配备齐全的圆形管中通过实验评估了分散在水中的Al ₂ O ₃纳米粒子的热性能。确定了在三个不同体积浓度（0.38％，0.81％和1.30％）下Al ₂ O ₃纳米流体的热物理性质随温度的变化。在不同的体积浓度和入口流体温度（10°C–30°C）下进行了压降和传热实验。Al ₂ O ₃纳米流体的整体性能通过考虑其水力和传热特性进行评估。实验结果表明，使用Al ₂ O_3种纳米流体由于具有更高的粘度而使压降最多增加了约13％。另外，由于增强的导热性，纳米流体的传热系数随着体积浓度而增加高达约19％。此外，实验结果表明，在最高进口流体温度下，体积分数为0.81％的纳米流体可以使整体性能提高约8％，并且比其他体积分数要好。总体性能的提高会随着入口流体温度的升高而增加，这是因为有效导热系数的提高和粘度的降低，分别增加了能量交换和压力损失。