竖直圆管内泡状流空泡份额径向分布实验研究

常温常压下，采用光学探针测量方法，对圆管（内径50 mm）内空气 水两相竖直向上泡状流空泡份额的径向分布特性进行了实验研究。结果表明，竖直圆管内泡状流空泡份额的径向分布随气液两相表观流速不同而变化。液相流速较高时空泡份额分布呈“壁峰型”，即中心区域变化平缓，近壁区出现峰值后迅速降低；液相静止时，随气相流速增加，空泡份额增加速度沿径向向外逐渐减小，气相流速较大时分布呈“核峰型”，即空泡份额随径向位置向外呈减小趋势；液相流速较低时分布呈现出过渡型。探针测量面积加权平均空泡份额与通过重位压降得到的空泡份额的相对偏差小于10%。

Experimental Investigation on Void Fraction Radial Distribution for Bubbly Flow in Vertical Circular Tube

The radial distribution of air-water two-phase upward bubbly flow in a vertical circular tube (ID 50 mm) was investigated experimentally by using the optical fiber probe under ambient temperature and pressure. The results show that the radial distribution of void fraction changes with different superficial gas and liquid velocities. The void fraction is almost invariable along radius except in the near wall region where it has a peak and then decreases sharply at high superficial liquid velocity which is called “wall peak”. In the case of stagnant liquid, the increasing rate for void fraction becomes slower as the radial position varies from the center to the wall with the increase of superficial gas velocity. When the superficial gas velocity increases, the void fraction decreases radially from the core to the wall location, namely “core peak”. When the liquid velocity is low, the void fraction distribution behaves as the transition pattern. The relative deviration of the probe measured area-weighted averaged void fraction against that based on pressure drop is less than 10%.