Abstract: A test bench of steam condensation inside a long horizontal tube under vacuum condition was established. An experimental study was carried out to observe the influences of inlet mass flow rate, content of condensate and saturation temperature on the liquid level angle of the condensate when steam continuously condenses inside a horizontal tube. The correlation of liquid level angle is presented. It is found that, at a lower mass flow rate of steam, the liquid level angle of condensate increases with the content of condensate and the growth rate is fluctuated. At a higher steam flow rate, due to the influence of steam flow, the liquid level angle decreases and its edge becomes vague. The liquid level angle increases with the increment of saturated temperature or saturated pressure at the same flow rate of steam. The correlation of liquid level angle proposed in this paper can well predict the liquid level angle and liquid level of condensate in a horizontal pipe.

Key words: liquid level angle, horizontal tube, two-phase flow, condensation, voidage

摘要： 建立了长水平管真空条件下蒸汽凝结实验台，观测了蒸汽在水平管内凝结过程的入口质量流率、凝结液含量和饱和温度对凝结液液位角变化的影响，归纳了液位角计算关系式。研究发现，较低蒸汽流量下，液位角随凝结液含量的增加呈波动增加；较高蒸汽流量下，受气流影响，液位角减小，液位角边缘模糊；在同样蒸汽流率条件下，饱和温度升高即压力升高，液位角会有所增加。给出的液位角关系式可用于计算水平管内凝结液液位和液位角。

关键词: 液位角, 水平管, 两相流, 凝结, 空隙率