Abstract

Numerical simulation of 2D Cryogenic Pulsating Heat Pipe (CPHP) is carried out with near critical diameter. Liquid nitrogen is used as working fluid for targeting cryogenic applications in the range from 77 to 123 K. The volume of fluid (VOF) model is considered for two phase simulations. The evaporator and condenser section are kept at constant wall temperature condition while adiabatic section is considered insulated. The evaporator temperature varied from 85 to 110 K and condenser section kept at 75 K. The filling ratio (FR) of working fluid is varied as 50, 60 and 70%. CPHP model is first tested with on ground gravity condition of 9.81 m/s². It is then tested with low gravity conditions (0.981 m/s²) and milli-gravity condition (0.01 m/s²). In low gravity condition, surface tension force is observed more dominant than body force which significantly altered the performance of a CPHP. In comparisons with ground level condition, more stable flow patterns are observed which led to the improved heat transfer performance of a CPHP in case of low gravity.

中文翻译：

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重力条件下近临界直径的低温脉动热管的CFD分析

摘要

在接近临界直径的条件下进行了二维低温脉动热管（CPHP）的数值模拟。液氮用作工作流体，用于77至123 K范围内的低温应用。两相模拟考虑了流体体积（VOF）模型。蒸发器和冷凝器部分保持在恒定的壁温条件下，而绝热部分被认为是绝热的。蒸发器温度从85到110 K不等，冷凝器段保持在75K。工作流体的填充率（FR）分别为50％，60％和70％。首先在地面重力条件为9.81 m / s ^2的情况下测试CPHP模型。然后在低重力条件（0.981 m / s ²）和毫重力条件（0.01 m / s ^{2）下进行测试}）。在低重力条件下，观察到表面张力比体力更重要，这大大改变了CPHP的性能。与地面条件相比，观察到更稳定的流动模式，这导致在低重力情况下CPHP的传热性能得到改善。