In the present study, two-phase flow and forced-convection heat transfer of hydrogen gas (H2) in a solar finned and baffled channel heat exchanger (SFBCHE) is studied numerically. The effect of different obstacles in the channel is addressed. A H2 heat transfer fluid (HTF) having a high thermal conductivity with the baffling technique is implemented to enhance the overall performance of a solar channel. In the initial step, the results from the proposed numerical model were compared with the experimental data of a smooth channel, and then against data with a baffled channel. After checking the validity of our model, the same numerical approach was used for studying thermal-fluid characteristics of the channel with the new fluid. A hydrothermal analysis is presented for a range of Reynolds number (Re) from 5000 to 25,000. At the lowest Re = 5000, the thermal enhancement factor (TEF) is about 1.25. This value increases to 2.16, or 73.46%, when Re = 10,000. This increase in the TEF values continues as Re increases. The largest Re = 25,000 gives the highest TEF value, as it is about 4.18, which is 2.75 times greater than that given for the case of using the conventional gaseous fluid (air). Therefore, our proposed structure for the SFBCHE with high H2 HTF flow velocity leads to improve the values of dynamic pressure (Pd) and heat transfer (Nu), while reducing the skin friction (f) values, which increases the overall TEF of the channel. In addition, all performance values are greater than unity (or 1.00). This reflects the importance of the H2 HTF baffling and finning technique in improving the hydrodynamic thermal-energy performance of solar heat exchangers. The suggested model of SFBCHE filled with an H2 HTF having a high thermal conductivity allows a considerable enhancement in the overall thermal performances which can be employed in various thermal types of equipment, such as solar energy receivers, automotive radiators, and cooling in chemical industries.

中文翻译：

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阻隔技术与高导热流体相结合，提升太阳能通道的整体性能

在本研究中，对太阳能翅片和折流通道换热器 (SFBCHE) 中氢气 (H2) 的两相流动和强制对流换热进行了数值研究。解决了通道中不同障碍物的影响。使用具有高导热性的 H2 传热流体 (HTF) 和挡板技术来提高太阳能通道的整体性能。在初始步骤中，将所提出的数值模型的结果与平滑通道的实验数据进行比较，然后与带有挡板的通道的数据进行比较。在检查我们模型的有效性后，使用相同的数值方法研究具有新流体的通道的热流体特性。提供了雷诺数 (Re) 范围从 5000 到 25,000 的水热分析。在最低 Re = 5000 时，热增强因子 (TEF) 约为 1.25。当 Re = 10,000 时，该值增加到 2.16，即 73.46%。TEF 值的这种增加随着 Re 的增加而继续。最大的 Re = 25,000 给出了最高的 TEF 值，因为它约为 4.18，是使用传统气态流体（空气）情况下给出的值的 2.75 倍。因此，我们为具有高 H2 HTF 流速的 SFBCHE 提出的结构提高了动态压力 (Pd) 和传热 (Nu) 的值，同时降低了表面摩擦 (f) 值，从而增加了通道的整体 TEF . 此外，所有性能值都大于 unity（或 1.00）。这反映了 H2 HTF 挡板和翅片技术在提高太阳能热交换器的流体动力热能性能方面的重要性。