In the current investigation, heat, flow characteristics, and exergy analysis of hybrid and single nanoparticles-based water passing through a triple ribbed tube heat exchanger (TRTHE) under several design and operation parameters are studied. A computational fluid dynamics (CFD) modeling is carried out using ANSYS-FLUENT 19 code while the validation criteria are accomplished with experimental data and empirical correlations in the literature. The model technique of 3D re-normalization group (RNG)/k–ϵ with enhanced wall treatment is chosen considering the conjugate heat transfer between the fluids. A user-defined function is utilized to specify the thermophysical properties of nanofluids and water based on the operating fluid temperature. The design and operating nanofluid velocity and temperature of inner, intermediate, and outer tubes are 0.7 m/s at 10 °C, 0.05–0.13 m/s at 70 °C, and 0.05 m/s at 18 °C, respectively. The ribs under consideration are trapezoidal, semi-circular, semi-elliptical, triangular, rectangular, and square-shaped and the tested perforated louver widths are 0.5, 1, 1.5, and 2 mm. Three hybrid combinations of nanomaterials (oxide/oxide, oxide/carbide, oxide/carbon nanotube) by constant volume percent of 50/50% are employed with water as a base fluid under a constant volume concentration of 0.1%. Four different kinds of nanoparticles are chosen as Al₂O₃, MgO, SiC, and MWCNT in order to perform the present study.

The obtained findings manifested that the hybrid nanofluid of Al₂O₃+MWCNT/H₂O achieves a higher heat transfer rate compared with single nanofluids. A lower rib louver width with semi-circular rib geometry and staggered rib arrangement leads to an increase in the Nusselt number and effectiveness of the TRTHE. The use of semi-circular rib shape produces a rise of dimensionless exergy loss rate by about 5.4–21.6% more than other rib shapes.

在当前的研究中，研究了在几种设计和运行参数下，通过三肋肋管式换热器（TRTHE）的混合水和单纳米颗粒水的热，流量特性和火用分析。使用ANSYS-FLUENT 19代码进行计算流体动力学（CFD）建模，同时使用文献中的实验数据和经验相关性来完成验证标准。考虑流体之间的共轭传热，选择具有增强壁处理的3D重归一化组（RNG）/ k–k模型技术。利用用户定义的功能可根据工作流体温度来指定纳米流体和水的热物理性质。内管，中管和外管的设计和操作纳流速度和温度为 在10  °C时为0.7 m / s， 在70  °C时为0.05–0.13 m / s， 在18  °C时为0.05 m / s 。所考虑的肋是梯形，半圆形，半椭圆形，三角形，矩形，和方形和测试穿孔百叶板宽度0.5，1，1.5和2 毫米。恒定体积浓度为0.1的三种混合纳米材料（氧化物/氧化物，氧化物/碳化物，氧化物/碳纳米管）以50 / 50％的恒定体积百分比与水作为基础液一起使用％。为了进行本研究，选择了四种不同类型的纳米颗粒作为Al ₂ O ₃，MgO，SiC和MWCNT。

获得的发现表明，与单个纳米流体相比，Al ₂ O ₃ + MWCNT / H ₂ O的混合纳米流体实现了更高的传热速率。具有半圆形肋骨几何形状和交错的肋骨排列的较低的肋骨百叶窗宽度导致Nusselt数量的增加和TRTHE的有效性。使用半圆形肋骨形状比其他肋骨形状产生的无因次热能损失率提高了约5.4 – 21.6％。