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为了深入考察竖直表面上滴状冷凝强化蒸汽冷凝传热过程的作用机理,设计了滴状冷凝(DWC)、膜状冷凝(FWC)两种冷凝形态的疏水和亲水竖直圆柱形表面,进行了实验研究。结果表明:在30 k Pa压力和相同过冷度的情况下,滴状冷凝传热量是膜状冷凝传热量的2~4倍。其主要原因是滴状冷凝时冷凝表面呈疏水性,使经过合并后的大液滴在形成连续的液膜前就从表面上脱落下来,蒸汽能够持续不断地与冷表面直接接触,其换热强度远远大于膜状冷凝。
In order to investigate the mechanism of heat transfer during the drop condensate condensation on a vertical surface, the hydrophobic and hydrophilic vertical cylindrical surfaces of two kinds of condensate forms of droplet condensation (DWC) and membrane condensation (FWC) An experimental study was carried out. The results show that at 30 kPa pressure and the same degree of undercooling, the droplet heat of condensation is 2 to 4 times of that of the film-like condensation. The main reason is that when condensing drops, the condensing surface is hydrophobic, so that the large droplets after the merging fall off from the surface before forming a continuous liquid film. The steam can directly contact with the cold surface continuously, and the heat transfer The intensity is far greater than the film-like condensation.