In this paper, a visualization experiment was conducted for multiphase flow in the evaporating hot water tower. The high-speed camera was used to record the motion of a single bubble above the 3 mm single-hole sieve tray in the hot water tower. The pictures were processed by image processing software to obtain the characteristics of the bubble. In the experiment, non-condensable gas was added to the steam as a carrier of particles. A mixture of gaseous N₂ and N₂/solid particles was used to study the effect of solid particles on bubble formation, collapse and motion processes. The correlation for the number of transfer units NTU_L is proposed. The experimental results show that the entire growth cycle of the bubble includes the formation region, the rising region and the oscillation region. The ratio of bubble length to diameter decreases from 1.13 to 0.80 in the formation region and surges to 1.3 in the rising region. The equivalent radius of the bubble increases throughout the entire cycle of motion, with the highest growth rate in the formation region and maximum radius of bubble not exceeding 20 mm. The centroid velocity rate of bubble in the formation region shows an increasing trend, and then fluctuates around 0.4 m/s in the rising region and the oscillation region. When N2 was entrained into the pulverized coal particles, it was found that the proportion of the rising region of the bubble was greatly reduced, and the proportion of the oscillation region increased significantly, which was conducive to the transfer of heat within the tower. The effect is more obvious when steam and nitrogen ratio α is less than 10.

本文针对蒸发热水塔中的多相流动进行了可视化实验。高速摄像机用于记录热水塔中3 mm单孔筛板上方的单个气泡的运动。图片由图像处理软件处理以获得气泡的特征。在实验中，将不可冷凝气体作为颗粒载体添加到蒸汽中。用气态N ₂和N ₂ /固体颗粒的混合物研究固体颗粒对气泡形成，塌陷和运动过程的影响。传输单位数量NTU _L的相关性被提议。实验结果表明，气泡的整个生长周期包括形成区，上升区和振荡区。气泡长度与直径之比在形成区域从1.13降低到0.80，在上升区域激增到1.3。气泡的等效半径在整个运动周期中都会增加，在地层区域中的增长率最高，气泡的最大半径不超过20 mm。气泡在形成区的质心速度呈上升趋势，然后在上升区和振荡区以0.4 m / s左右波动。当将N 2夹带到煤粉颗粒中时，发现气泡上升区域的比例大大降低，振荡区域的比例显着增加，这有利于塔内热量的传递。当水蒸气和氮气比α小于10时，效果更明显。