基于VOF模型和改进的相变模型对热虹吸管稳态相变传热过程进行CFD模拟,根据温度分布实验数据和可视化实验进行验证,并分析充液率对热管蒸发?冷凝传热行为的影响.研究结果表明:CFD模型能够较准确地描述热管工质的蒸发和冷凝过程,模拟得到热管各段均温的最大偏差为10.2 K,相对误差2.9%,采用改进的相变模型,温度分布模拟值与实验值一致性更好;模拟得到蒸发段工质流型转变过程与可视化实验定性相符;热管冷凝段以膜状冷凝传热为主,充液率的改变对其影响不大,充液率主要影响蒸发段的传热行为,进而影响热管的传热性能.该工作有助于对热管运行机理的理解,并为其CFD模拟提供指导.%A computational fluid dynamic (CFD) model based on the volume of fluid (VOF) multiphase model and an improved phase change model were developed to simulate the phase change heat transfer process in thermosyphons at steady state, and the modeling results were validated by measuring wall temperature distribution and visualization experiments. Besides, the influence of filling ratio (FRs) on the evaporation-condensation behavior in thermosyphons was analyzed. The results show that this CFD model can reproduce both the vaporization and condensation processes well. The predicted temperature distribution show better consistency with experimental results using the improved phase change model, the maximum deviation of average temperature at different sections being 10.2 K with a relative deviation of 2.9%. Furthermore, the predicted flow regimes are generally in agreement with the observed phenomenon in visualization testing. Filmwise condensation is the main heat transfer mode at condenser area in thermosyphons which is not affected by FRs. However, the variation of FRs considerably affects the heat transfer behavior at evaporator and thus changes the heat transfer performance of thermosyphons. This study is conducive for understanding the operating mechanism of thermosyphons and meanwhile provides some guidance for its CFD modeling.
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