矩形窄缝通道低压低流速流动不稳定起始点实验研究

Experiment Investigation on Onset of Flow Instability in Narrow Rectangular Channel under Low Pressure and Low Mass Flux Condition

摘要: 针对截面为40 mm×3 mm的竖直矩形窄缝通道，在低压低流速条件下，对其流动不稳定起始点(OFI)进行了可视化实验研究。观察到了OFI出现时通道内对应的汽泡以及流型分布等微观特征；基于可视化观察结果，定性分析了OFI出现的内在机理；获得了主要热工水力参数对OFI的影响规律；采用本实验获得的数据，对现有的OFI预测关系式进行了定量评价。结果表明：以饱和点参数为变量得到的关系式基本都能与本实验数据较好地吻合。

Abstract: The visualized experimental investigations were carried out on the phenomena of onset of flow instability (OFI) at low pressure and low mass flux condition in a vertical narrow rectangular channel with the section of 40 mm×3 mm. The bubble behavior and flow pattern distribution at OFI were visualized and then the mechanism of OFI was analyzed qualitatively. The effects of thermal-hydraulic parameters on OFI were preformed. Based on the experimental data, existing OFI predicted correlations were evaluated. The results show that the correlations, which adopt the parameters at saturation point as the independent variables, can predict the experimental data reasonably.