聚四氟乙烯薄膜表面滴状冷凝传热实验研究

为了探索实现滴状冷凝传热的新表面涂层 ,采用离子束动态混合注入技术制备了紫铜基聚四氟乙烯(PTFE)薄膜 ,显著地提高了水蒸气冷凝传热性能。实验表明 ,该表面涂层能够实现常压水蒸气稳定的滴状冷凝形态 ,在表面过冷度 9.8— 1 4 .2K范围内 ,滴状冷凝传热通量和传热系数比膜状冷凝结果提高 30—47倍。同时发现 ,在大气压附近 ,热通量和冷凝传热系数都随着水蒸气蒸汽温度的增加而增加 ,但表面过冷度随蒸气温度增加呈弱增加趋势

Experimental Study of Steam Dropwise Condensation on Polytetrafluoroethylene Film

To investigate new surface materials for promotion of steam dropwise condensation heat transfer mode, the dynamic ion beam mixed implantation (DIMI) method was employed to coat polytetrafluoroethylene (PTFE) film on a copper plate. It was found that steady dropwise condensation of steam was observed and the condensation heat transfer characteristics were considerably enhanced. The dropwise condensation heat transfer coefficient and heat flux were increased by 30 to 47 times compared with values of bare surface at the surface subcooling degree ranging from 9.8 K to 14.2 K. The experimental results also demonstrated that the condensation heat flux and heat transfer coefficient were increased with the steam temperature rising near atmosphere pressure, whilst the surface subcooling degree tended toward a weak increase as rise of vapor temperature.