The pressure vessel has used a newly designed water seal structure, and the sealed water is from condensation at low hydrogen concentration. To get the condensation capacity of the water seal branch tube under the pressure vessel normal operation, the experimental loop named WASETEL was constructed, which is aimed at studying the heat transfer during the process of air-steam mixture condensation inside the inclined branch tube at the condition of low air mass fraction. The inner tube is diameter 0.134 m with length 0.68 m which is connected with diameter 1.4 m, high 2.5 m pressure vessel. A canon camera was set to record the images and videos of the condensate height through glass tube in communicating vessel liquidometer. The experiment was conducted under the pressure ranged from 0.2 to 0.6 MPa, air mass concentration ranged from 0.49 to 6.42% and wall subcooling ranged from 11 to 40 K. The test showed HTC (heat transfer coefficient) would sharply deteriorate with the small air fraction, compared with pure steam condensation, about 0.49% mass fraction of the air will reduce heat transfer coefficient by 70–80%. When air concentration is relatively small, those widely used relations can not predict the condensation well, therefore, a new heat transfer empirical correlation with air mass fraction, pressure and subcooling is proposed, covered all the experimental data within the error band ±13%.

压力容器采用了新设计的水封结构，密封后的水来自低氢浓度的冷凝水。为了获得压力容器正常运行下水封支管的冷凝能力，构建了名为WASETEL的实验回路，旨在研究在斜支管内的空气-蒸汽混合物冷凝过程中的热传递。空气质量分数低的情况。内管的直径为0.134 m，长度为0.68 m，该内管与直径为1.4 m，高2.5 m的压力容器相连。设置了一个佳能相机以通过连通容器液体计中的玻璃管记录冷凝水高度的图像和视频。实验是在0.2至0.6 MPa的压力，0.49至6的空气质量浓度范围内进行的。42％的空气过冷度为11至40K。测试表明，空气分数较小时，HTC（传热系数）会急剧降低，与纯蒸汽冷凝相比，约0.49％的空气质量分数会降低传热系数。 70–80％。当空气浓度相对较小时，那些广泛使用的关系不能很好地预测冷凝，因此，提出了一种新的与空气质量分数，压力和过冷度有关的传热经验关系式，覆盖了误差范围±13％以内的所有实验数据。