超亲水-疏水组合竖直表面强化蒸汽冷凝传热

Steam Condensation Heat Transfer Enhancement on Superhydrophilic-Hydrophobic Hybrid Vertical Surface

为了强化蒸汽冷凝传热,设计超亲水-疏水组合表面,研究了超亲水网格线间距、壁面过冷度等参数对蒸汽冷凝传热的影响。组合表面上超亲水网格线之间间距分别为1.5 mm、2.5 mm、3.5 mm,并将组合表面的传热性能与光滑表面和疏水表面进行了对比,同时使用高速摄影仪对组合表面蒸汽冷凝过程进行了可视化。研究发现,超亲水-疏水组合表面可以较好地调控冷凝液滴大小,其冷凝传热性能要优于光滑表面和疏水表面。在△T=4.3 K时,2.5 mm间距组合表面的传热系数分别是光滑表面和疏水表面的2.2倍和1.6倍。而在三个超亲水网格线间距的组合表面中,网格间距为2.5 mm的组合表面传热性能最佳。在△T=9.0 K时,2.5 mm间距组合表面的传热系数分别是1.5 mm间距组合表面和3.5 mm间距组合表面传热系数的1.2倍和1.8倍。

To strengthen steam condensation heat transfer, superhydrophilic-hydrophobic hybrid surface is designed. The effects of parameters such as superhydrophilic grid line spacing and wall undercooling on steam condensation heat transfer are studied and superhydrophilic grid line spacing on hybrid surface is 1.5 mm, 2.5 mm and 3.5 mm respectively. The heat transfer performance of hybrid surface compares with smooth surface and hydrophobic surface, and the process of hybrid surface steam condensation is visualized using a high-speed camera. It is found that superhydrophilic-hydrophobic hybrid surface can better regulate the condensate droplet size, and its condensation heat transfer performance is better than that of smooth surface and hydrophobic surface. At △T= 4.3 K, the heat transfer coefficient of the 2.5 mm grid spacing hybrid surface is 2.2 times and 1.6 times of the smooth surface and hydrophobic surface respectively. In the three superhydrophilic grid line spacings hybrid surface, the heat transfer performance of 2.5 mm grid spacing hybrid surface is overall best, and at △T= 9.0 K, the heat transfer coefficient of the 2.5 mm grid spacing hybrid surface is 1.2 times and 1.8 times of 1.5 mm grid spacing hybrid surface and 3.5 mm grid spacing hybrid surface, respectively.