单面加热矩形窄缝通道流型可视化研究

Visualized Experimental Observation on Flow Patterns in a Single-Side Heated Narrow Rectangular Channel

针对截面为40 mm×3 mm的竖直矩形窄缝通道,在低压以及入口温度过冷的条件下,对水流动沸腾的流型特征进行了可视化实验观察。观察到弥散泡状流、合并汽泡流、搅拌流和环状流4种流型;获得了矩形窄缝通道内流型的二维可视化图像,为流型的确认提供了直观的依据;对实验数据进行了初步分析,绘制了单面加热矩形窄缝通道内水流动沸腾的流型图。将本实验数据与现有的典型流型图进行了初步的对比分析,结果表明加热蒸汽-水的流型及其转变规律与绝热空气-水的差异明显。

Visualized experimental observation on flow patterns during the flow boiling of water under single-side heated and fluid-inlet sub-cooled conditions in a vertical narrow rectangular channel with the section of 40×3mm2 were carried out.Four discernible flow patterns which were dispersed bubbly,and the coalesced bubbly,churn flow and annular flow were observed.Flow visualization in two dimensions of two-phase flow patterns for narrow rectangular channel,which provided intuitionistic evidence to distinguish flow patterns,were performed.Based on the experiment results,a flow pattern map for the single-side heated narrow rectangular channel was developed and then compared with some existing flow pattern maps.The comparison result showed that the flow patterns and its transition mechanisms are obviously different between the heated steam-water flows and the adiabatic air-water flows.