Velocity of Liquid Lumps in Vertical Upward Gas-Liquid Two-Phase Flow in Capillary Tubes.

To elucidate the effect of tube diameter on the vertical upward gas-liquid two-phase flow in capillary tubes, characteristics of velocity and flow behavior of liquid lumps (namely, liquid slug, huge wave and disturbance wave) are investigated experimentally. The tube diameters were changed from the maximum value of 26.0mm to the minimum value of 0.5mm. In the flow regimes of the huge wave and disturbance wave, the effect of tube diameter on the velocity of liquid lumps is distinctly recognized. When the diameter decreases from 26.0mm, the velocity of liquid lumps gradually increases, but it drastically decreases when the diameter is less than 2.0mm.