Prediction and a New Correlation of Holdup in Gas-Liquid Two-Phase Flow in Vertical Rectangular Capillary Channels.

The measurement of time varying holdup was conducted for vertical upward gas-liquid twophase flows in capillary channels with four kinds of different rectangular cross section. Each test section has the dimension of 1 mm×1 mm, 2 mm×1 mm, 5 mm×1 mm and 9.9 mm×1.1 mm. The equivalent diameters and the aspect ratios were respectively changed from 1 to 2 mm and 1 to 9. Almost all the correlations already proposed so far, which were based on the data of larger scale rectangular ducts, were clarified not to be applicable to the present data of the capillary channel. As a result we proposed a new correlation and an estimation method of holdup by using those measured data. In the correlation the effects of surface tension and viscosity are taken into consideration. The applicability and the modification of the correlation for the data of the larger scale duct were also investigated.