With a single-phase approach, a 3D mathematical model was developed through Computational Fluid Dynamics (CFD) techniques, coupling the momentum and heat transfer balances for the study of the thermal behaviour of nanofluids. The local heat transfer coefficient and thermal boundary layer thickness of CuO/water, Fe2O3/water and Al2O3/water nanofluids, have been predicted and compared with those experimentally determined at three volume concentration of nanoparticles (ϕ=0.01%, 0.03% and 0.05%), at T = 25 °C and T = 55 °C for laminar and turbulent flow conditions, using a newly developed sophisticated noninvasive heat transfer coefficient probe that is flush mounted on the inner wall of the test section. Such conditions have been used for the mathematical model, considering the effects of the nanoparticle materials and volume concentrations through effective thermophysical properties. The predicted results from the mathematical model show a good agreement with the trend and the experimental observations. The enhancement of the heat transfer coefficient and reduction of the thermal boundary layer when increasing the volume concentration of the nanofluids and when increasing the flow rates have been properly predicted by the mathematical model results, showing average absolute relative errors between 1.7% and 8.4%. The model exhibits an enhancement in the agreement between the experimental measurements and the predicted results when comparing with other models found in literature.

采用单相方法，通过计算流体动力学（CFD）技术开发了3D数学模型，结合了动量和传热平衡，以研究纳米流体的热行为。已经预测了CuO /水，Fe2O3 /水和Al2O3 /水纳米流体的局部传热系数和热边界层厚度，并与在三种体积浓度的纳米颗粒上实验确定的值进行了比较（ϕ层流和湍流条件下，在T = 25°C和T = 55°C时，使用全新开发的精密非侵入式传热系数探头，将其在T = 25°C和T = 55°C时分别为0.01％，0.03％和0.05％）。测试部分。考虑到纳米颗粒材料和通过有效热物理性质产生的体积浓度的影响，这些条件已用于数学模型。数学模型的预测结果与趋势和实验观察结果吻合良好。数学模型结果正确预测了当增加纳米流体的体积浓度时和当增加流速时传热系数的增加和热边界层的减少，显示出平均绝对相对误差在1.7％和8.4％之间。