窄缝通道内过冷条件下单蒸汽泡尾流特性实验研究

单蒸汽泡尾流特性是影响窄缝通道内蒸汽-水两相流流型形成与演变的关键因素，本文采用粒子图像测速仪PIV和Insight3G后处理软件，对窄缝通道内过冷条件下单蒸汽泡的尾流特性进行研究，获得窄缝通道内单蒸汽泡的尾流特性。实验结果表明，单蒸汽泡冷凝上升过程中，其尾流均为涡交替脱落的不对称尾流结构；汽泡直径越大，涡越细长，涡强度越大，大直径蒸汽泡的尾流对周围汽泡的作用更强；流道间隙减小，则尾流中涡强度降低，流体速度减小，尾流对周围汽泡的影响会相应减弱。单蒸汽泡尾流特性为构建窄缝通道内蒸汽-水两相流模型提供基础支持。 

Experimental Study on Wake of Single Vapor Bubble under Subcooling Condition in a Narrow Channel

The wake of single vapor bubbles is a key factor affecting the flow regime formation and the evolution of vapor-water two phase flows in narrow channels. The wake of single vapor bubbles were examined under subcooling conditions in a narrow rectangular channel using Particle Image Velocimetry and post processed software Insight3G. Results showed that the wake structures were asymmetric with the vortex shed alternately in bubble rising process. The larger the bubble is, the stronger and the longer the vortex and the vortex strength are. As a result, the wake of large-diameter vapor bubble has a stronger effect on the surrounded bubbles become stronger. When the channel gap decreases, the strength and fluid velocity of the wake weaken, so as to the influence on the surrounded bubbles. Wake characteristics of single vapor bubbles can provide basic support for two phase flow model construction in narrow channels.