正方形小通道内气液两相流垂直向上流动特性

辅助高速摄影仪对正方形小通道内氮气-水两相流向上流动进行可视化观察，对流动特性进行了实验研究，获得了典型的流型图像。采用数字图像处理技术对流型图像进行了处理，检测得到气相的周长、面积，并通过提出的假想圆柱体模型计算和统计得到了截面含气率。将压降实验数据分析结果与典型的分相流、均相流压降模型预测值比较，结果表明，Chisholm关系式能较好地预测两相流的压降变化，Lee & Lee关系式和Dukler关系式可较好地预测低表观速度时的两相流压降。

Flow characteristics of gas-liquid two-phase flow in small vertical square channel

Based on the observed flow pattern by high speed camera, experimental study was conducted to investigate flow characteristics for nitrogen and water flows in a vertical square mini-channel with hydraulic diameter of 1 mm.The perimeter and area of gas phase was calculated with a method of image processing technique.The void fractions were obtained by computing the parameters with the proposed hypothetical cylinder model.Comparisons with the literature available showed that the Chisholm model provided the best agreement with experimental data.For low superficial velocities, the Lee & Lee model and Dukler model showed a better predictive ability than the other experimental correlations.