Combination of baffling technique and high-thermal conductivity fluids to enhance the overall performances of solar channels
Combination of baffling technique and high-thermal conductivity fluids to enhance the overall performances of solar channels
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DOI：
10.1007/s00366-020-01165-x
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发表时间：
2020-09
影响因子：
8.7
通讯作者：
Y. Menni;Mahyar Ghazvini;H. Ameur;Myeongsub Kim;M. Ahmadi;M. Sharifpur
中科院分区：
文献类型：
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作者：
Y. Menni;Mahyar Ghazvini;H. Ameur;Myeongsub Kim;M. Ahmadi;M. Sharifpur
本文对太阳能翅片折流板换热器（SFBCHE）内氢气的两相流动和强制对流换热进行了数值研究。讨论了通道中不同障碍物的影响。采用了具有高导热系数的h2传热流体（HTF）和挡板技术，以提高太阳能通道的整体性能。首先，将数值模型的结果与光滑通道的实验数据进行比较，然后与挡板通道的实验数据进行比较。在验证了模型的有效性后，采用相同的数值方法研究了含新流体的通道热流体特性。对雷诺数（Re）从5000到25000的范围进行了水热分析。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%。这种TEF值的增加随着Re的增加而持续。最大的Re = 25,000给出了最高的TEF值，约为4.18，是使用常规气态流体（空气）的情况下给出的2.75倍。因此，我们提出的具有高H2HTF流速的SFBCHE结构可以提高动压（Pd）和换热（Nu）值，同时降低表面摩擦(f)值，从而提高通道的整体TEF。此外，所有性能值都大于1（或1.00）。这反映了H2HTF折流翅片技术对提高太阳能换热器流体动力热能性能的重要性。所建议的SFBCHE模型填充了具有高导热性的H2HTF，可以显着提高整体热性能，可用于各种热设备，如太阳能接收器，汽车散热器和化学工业的冷却。
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 H2heat 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 H2HTF 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 H2HTF baffling and finning technique in improving the hydrodynamic thermal-energy performance of solar heat exchangers. The suggested model of SFBCHE filled with an H2HTF 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.