Supercritical cryogenic fluids exhibit significant potential for diverse applications across various industries, including liquid air energy storage, high-temperature superconducting cables, and hypersonic vehicle engine cooling. Heat transfer deterioration (HTD) poses a substantial risk to the system safety. In this study, we constructed an experimental system and performed numerical simulations to illustrate buoyancy () and thermal acceleration () effects on HTD of supercritical nitrogen (SCN). The newly established thresholds for buoyancy and thermal acceleration (=1.8×10 and =4.4×10), considering pseudo two-phase characteristics, can effectively capture buoyancy and thermal acceleration in the first and second HTD regions. The first region is influenced by the combined effect of buoyancy and thermal acceleration, while the second region is mainly influenced by thermal acceleration. The new correlations and thresholds accurately predict the occurrence of HTD and the peak position. The experimental and simulation results contribute to understanding the impact of buoyancy and thermal acceleration on SCN HTD.

中文翻译：

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超临界氮气立管传热恶化的实验与数值研究


超临界低温流体在各个行业的不同应用中展现出巨大的潜力，包括液态空气储能、高温超导电缆和高超音速车辆发动机冷却。传热恶化（HTD）对系统安全构成重大风险。在这项研究中，我们构建了一个实验系统并进行了数值模拟，以说明浮力 () 和热加速 () 对超临界氮气 (SCN) 的 HTD 的影响。新建立的浮力和热加速度阈值（=1.8×10和=4.4×10）考虑伪两相特性，可以有效捕获第一和第二HTD区域的浮力和热加速度。第一个区域受浮力和热加速度的综合影响，而第二个区域主要受热加速度的影响。新的相关性和阈值可以准确预测 HTD 的发生和峰值位置。实验和模拟结果有助于理解浮力和热加速度对SCN HTD的影响。