Abstract Cryogenic fluids such as Liquid Helium (LHe), Liquid Nitrogen (LN2), Liquid Oxygen (LOX) and Liquid Hydrogen (LH2) played a vital role in cooling various superconducting devices. The boiling temperatures of cryogenic fluids being lower than the critical temperature of the superconductors have enabled such an advantage. Moreover, supercritical fluids such as Supercritical Helium (SHe) and Supercritical Nitrogen (SCN) are also found to be replacing the liquid coolants thereby eliminating the possibility of reduction in heat transfer due to multiphase flow of working fluid. Hence, it is essential to investigate the role of such supercritical fluids in cooling the superconducting cables. Hence, in the present work, Super Critical Nitrogen (SCN) is proposed as a coolant for cooling of High Temperature Superconducting (HTS) cables. As the thermophysical properties are strongly affected by the temperature, analytical functions of thermophysical properties of SCN such as viscosity, density, specific heat and thermal conductivity are developed and implemented in the Thermohydraulic analysis of 1 m HTS cable. A 3-Dimensional computational model of HTS cable is modeled and developed in commercial software ANSYS-FLUENT for solving governing equations of mass, momentum and energy simultaneously. Different mass flow rates ranging from 16 L/min to 20 L/min and heat loads ranging from 1 W/m to 3 W/m are considered in estimating the thermohydraulic performance of HTS Cable. Friction factor, pressure drop, pumping power and heat transfer rate are estimated and compared with the results of experiments available in the literature. It can be concluded that SCN may be used as coolant to cool the HTS cables having higher critical temperature.

中文翻译：

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超临界氮 (SCN) 对未来高温超导 (HTS) 电缆的液压和热特性的作用

摘要 液氦 (LHe)、液氮 (LN2)、液氧 (LOX) 和液氢 (LH2) 等低温流体在冷却各种超导器件中起着至关重要的作用。低温流体的沸腾温度低于超导体的临界温度，从而实现了这样的优势。此外，还发现超临界流体如超临界氦 (SHe) 和超临界氮 (SCN) 也正在取代液体冷却剂，从而消除了由于工作流体的多相流动而导致传热降低的可能性。因此，有必要研究这种超临界流体在冷却超导电缆中的作用。因此，在目前的工作中，建议使用超临界氮 (SCN) 作为冷却高温超导 (HTS) 电缆的冷却剂。由于热物理特性受温度的影响很大，因此在1 m HTS电缆的热工水力分析中开发并实现了SCN热物理特性的分析函数，例如粘度、密度、比热和导热率。在商业软件 ANSYS-FLUENT 中建模和开发了 HTS 电缆的 3 维计算模型，用于同时求解质量、动量和能量的控制方程。在估算 HTS 电缆的热工水力性能时，考虑了从 16 L/min 到 20 L/min 的不同质量流量和从 1 W/m 到 3 W/m 的热负荷。估计摩擦系数、压降、泵送功率和传热率，并与文献中可用的实验结果进行比较。