Velocity of Liquid Lumps in Vertical Upward Gas-Liquid Two-Phase Flow in Capillary Tubes. Effect of Tube Diameter in Annular Flow.

An experimental investigation was made to clarify the effects of tube diameter on the velocity, frequency, wavelength and wave height of liquid lumps in vertical upward gas-liquid two-phase flow in capillary tubes. The capillary tubes were of six different diameters ranging from 6.0 to 0.5 mm. The results of the statistical quantities of the liquid lumps reveal that the waves in the capillary tubes are roughly divided into two groups ; i. e., one has relatively high velocity with long wavelength and high wave height, and the other has low velocity with short wavelength and low wave height. The former is dominant in the tubes of diameters larger than 4.0 mm and the latter is dominant in the tubes of diameters less than 0.9 mm. Both waves coexist in the tubes of diameters between 2.0 and 1.45 mm.