水、丙酮混合工质振荡热管传热性能

采用水、丙酮以及其二元混合工质对振荡热管进行实验研究，选取35%～70%充液率，10～100 W加热功率以及水/丙酮13：1、4：1、1：1、1：4、1：13配比，将实验数据与混合工质物性、相变特点结合以研究其振荡热管传热性能。结果表明：混合溶液振荡热管启动所需功率小于水；小充液率时，除较低丙酮比例配比（如水/丙酮13：1混合工质）以外，混合工质比纯工质振荡热管不容易烧干，纯工质振荡热管在50 W时热阻就已经上升到较高数值，而混合工质振荡热管在同样的功率则维持着较低的热阻。在丙酮中加入少量水（如水/丙酮1：13混合工质）能有效改善振荡热管烧干情况，然而，少量丙酮与水混合而成的工质（如水/丙酮13：1混合工质）对振荡热管烧干情况的改善不明显；大充液率时，混合工质振荡热管的传热性能要弱于纯工质，在35～50 W，纯工质振荡热管热阻都低于混合工质，而在较大加热功率（50～100 W），水与混合工质振荡热管仍保持着较明显的热阻差。对混合工质振荡热管的传热性能的分析可为今后更深入研究其工作机理以及传热特性理论模型的建立提供参考。

Heat transfer performance of pulsating heat pipes with water-acetone mixtures

Experiments of pulsating heat pipes (PHP) were conducted, with water, acetone and water/acetone binary mixtures at different ratios (13:1, 4:1, 1:1, 1:4, 1:13) under various filling ratios (35%-70%) and heat inputs (10-100 W). The experimental results were analyzed with the feature of physical property and phase change for mixture. The results show that because of lower boiling point, specific heat and latent heat for evaporation, the mixture solution requires lower heating power to initial PHP than water. At low filling ratios, compared to mixtures except that with relatively low acetone concentration (e.g. water/acetone 13:1), pure working fluids are relatively easier to dry out in PHP. With the heat input of 50 W, PHPs with pure working fluid are dried, while those with mixtures maintain relatively low thermal resistance. The mixture with a little water (e.g. water/acetone 1:13) can significantly improve the dry state in PHP, while that with a little acetone (e.g. water/acetone 13:1) does not significantly improve the dry situation. At high filling ratios, heat transfer performance of PHP with pure working fluids are better than mixtures. In the range from 35 W to 50 W, the PHPs with pure working fluids present lower thermal resistance. At higher heat input (50-100 W), the PHP with water has lower thermal resistance compared to that with mixture. The study on heat transfer performance of PHP provides references for further research on the heat transfer mechanism of PHP and establishment of theoretical models on heat transfer characteristics.