The present work considers a shell-and-coil heat exchanger, and the hybrid nanofluid's flow and heat transfer inside the proposed thermal system are numerically evaluated. The coil tube has a conical pattern and is oriented horizontally inside the shell. Three water-based hybrid nanofluids are considered here as heat transfer fluids. A commercial CFD code that uses the finite volume method performs the numerical analysis. The regime of fluid flow is turbulent in both coil and shell sections. The validation analysis of the present numerical model was performed using the experimental results of the reference, and accordingly, the accuracy of the present numerical model was proved. This work includes two sectors. In the first part, the volume concentration of the considered hybrid nanofluid was kept constant, and the influence of the hybrid nanofluid kind on the hydrothermal behaviour of the shell-conical-coil heat exchanger was evaluated numerically. In this section, three hybrid nanofluids, (i) Water/MgO–TiO, (ii) Water/MOS-CuO, and (iii) Water/Ag-HEG, were employed. Also, for all suggested hybrid nanofluids, the volume concentration of both employed nanoparticles are equal to each other, φ = φ. The obtained outcomes depicted that between various considered heat transfer fluids, the Water/MgO–TiO model displayed the most outstanding thermal performance value in all the investigated Dean numbers, and the model Water/MOS-CuO was in second place. Moreover, the maximum thermal performance for the hybrid nanofluid was obtained at φ = φ = 0.7. The Ag-HEG/Water and MgO–TiO/Water hybrid nanofluids have the lowest and maximum thermal performance at the lowest considered Dean number among the evaluated hybrid nanofluids. As a result, the MgO–TiO/Water hybrid nanofluid has roughly 18.95 % higher thermal performance than the Ag-HEG/Water hybrid nanofluid. Furthermore, the MgO–TiO/Water and Ag-HEG/Water hybrid nanofluids have the highest and lowest thermal performance at the highest considered Dean number, respectively. Consequently, the MgO–TiO/Water hybrid nanofluid exhibits approximately 39.22 % higher thermal performance than the Ag-HEG/Water hybrid nanofluid. The MgO–TiO/Water hybrid nanofluid has the highest and lowest thermal performance at the lowest Dean number, with φ = φ = 0.7 and φ = φ = 0.3, respectively. The φ = φ = 0.7 model has a thermal performance that is approximately 39.28 % greater than the φ = φ = 0.3 model at the lowest regarded Dean number. At the highest regarded Dean number, the MgO–TiO/Water hybrid nanofluid with φ = φ = 0.3 exhibits a lower thermal performance than the model φ = φ = 0.7 by about 14.28 %.

中文翻译：

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壳式和锥形盘管换热器中混合纳米流体流动的水热行为；数值方法

目前的工作考虑了壳盘式热交换器，并对所提出的热系统内混合纳米流体的流动和传热进行了数值评估。盘管具有圆锥形图案，并在壳体内水平定向。这里考虑三种水基混合纳米流体作为传热流体。使用有限体积法的商业 CFD 代码执行数值分析。盘管和壳体部分的流体流动状态都是湍流。利用参考文献的实验结果对本数值模型进行了验证分析，证明了本数值模型的准确性。这项工作包括两个部分。在第一部分中，所考虑的混合纳米流体的体积浓度保持恒定，并数值评估了混合纳米流体类型对壳-锥形-盘管换热器水热行为的影响。在本节中，采用了三种混合纳米流体：(i) 水/MgO-TiO、(ii) 水/MOS-CuO 和 (iii) 水/Ag-HEG。此外，对于所有建议的混合纳米流体，所使用的两种纳米粒子的体积浓度彼此相等，φ = φ。获得的结果表明，在各种考虑的传热流体中，水/MgO-TiO 模型在所有研究的 Dean 数中表现出最出色的热性能值，而水/MOS-CuO 模型位居第二。此外，混合纳米流体的最大热性能是在 φ = φ = 0.7 时获得的。在所评估的混合纳米流体中，Ag-HEG/水和 MgO-TiO2/水混合纳米流体在考虑最低迪安数时具有最低和最高的热性能。因此，MgO-TiO2/水混合纳米流体的热性能比 Ag-HEG/水混合纳米流体高约 18.95%。此外，MgO-TiO2/水和Ag-HEG/水混合纳米流体在考虑的最高迪恩数下分别具有最高和最低的热性能。因此，MgO-TiO2/水混合纳米流体的热性能比 Ag-HEG/水混合纳米流体高约 39.22%。 MgO-TiO2/水混合纳米流体在最低迪恩数下具有最高和最低的热性能，分别为 φ = φ = 0.7 和 φ = φ = 0.3。在最低的 Dean 数下， φ = φ = 0.7 模型的热性能比 φ = φ = 0.3 模型高出约 39.28 %。在最高的 Dean 数下，φ = φ = 0.3 的 MgO-TiO2/水混合纳米流体的热性能比模型 φ = φ = 0.7 低约 14.28%。