In the present study, the heat transfer characteristics, namely, heat transfer coefficient, Nusselt number, pressure drop, friction factor and performance evaluation criteria are evaluated for water, Al₂O₃ and Al₂O₃/Cu nanofluids. The effects of Reynolds number, volume fraction and composition of nanoparticles in hybrid nanofluid are analyzed for all heat transfer characteristics. The single particle and hybrid nanofluids are flowing through a plain straight tube which is symmetrically heated under uniform heat flux condition. The numerical model is validated for Nusselt number within 7.66% error and friction factor within 8.83% error with corresponding experimental results from the previous literature study. The thermophysical properties of hybrid nanofluid are superior to the single particle nanofluid and water. The heat transfer coefficient, Nusselt number and pressure drop show increasing trend with increase in the Reynolds number and volume fraction. The friction factor shows the parabolic trend, and the performance evaluation criteria shows small variations with change in Reynolds number. However, both friction factor and performance evaluation criteria have increased with increase in the volume fraction. The 2.0% Al₂O₃/Cu with equal composition of both nanoparticles (50/50%) have presented superior heat transfer characteristics among all working fluids. Further, the heat transfer characteristics of 2.0% Al₂O₃/Cu hybrid nanofluid are enhanced by changing the nanoparticle compositions. The performance evaluation criteria for 2.0% Al₂O₃, 2.0% Al₂O₃/Cu (50/50%), 2.0% Al₂O₃/Cu (75/25%) and 2.0% Al₂O₃/Cu (25/75%) are evaluated as 1.08, 1.11, 1.10 and 1.12, respectively.

中文翻译：

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均匀加热管中单颗粒和杂化纳米流体传热特性的数值研究

在本研究中，评估了水，Al ₂ O ₃和Al ₂ O ₃的传热特性，即传热系数，努塞尔数，压降，摩擦系数和性能评估标准。/ Cu纳米流体。对于所有传热特性，分析了杂化纳米流体中雷诺数，体积分数和纳米颗粒组成的影响。单颗粒和杂化纳米流体流过一个普通的直管，该管在均匀的热通量条件下被对称加热。数值模型的误差在7.66％以内的Nusselt数和误差在8.83％以内的摩擦因数进行了验证，并具有先前文献研究的相应实验结果。杂化纳米流体的热物理性质优于单颗粒纳米流体和水。随着雷诺数和体积分数的增加，传热系数，努塞尔数和压降均呈增加趋势。摩擦系数显示出抛物线趋势，并且性能评估标准显示，随着雷诺数的变化，变化很小。但是，摩擦系数和性能评估标准都随着体积分数的增加而增加。铝含量为2.0％在所有工作流体中，具有相同组成的两种纳米颗粒（50/50％）的₂ O ₃ / Cu具有出色的传热特性。此外，通过改变纳米粒子组成，可以提高2.0％Al ₂ O ₃ / Cu杂化纳米流体的传热特性。性能评价标准2.0％的Al ₂ ö ₃，2.0％的Al ₂ ö ₃ /铜（50/50％），2.0％的Al ₂ ö ₃ /铜（75/25％）和2.0％的Al ₂ ö ₃ /铜（25/75％）的评估分别为1.08、1.11、1.10和1.12。