Fluctuation of Void Ratio in Two-Phase Flow : (3rd Report, Absolute Velocities of Slugs and Small Bubbles, and Distribution of Small Bubbles in Liquid Slugs)

Abstract

This paper has presented the formulas to calculate the absolute velocities of the gas slug (Taylor bubble) w_B, the small bubbles in the liquid slug section w_S, the liquid in the liquid slug w_w and the liquid film around gas slug w_F by the mean void ratio and gas time ratio. The experimental values of the absolute velocities are expressed by the following empirical formulas for air-water two-phase upward flow in 27.6 mm I.D. tube. w_B=1.25(w_wo+w_do) ; w_S=1.10 (w_wo+w_do) ; w_W=0.96(w_wo++w_d0) Also the absolute velocity of the gas slug has been directly measured. The distribution characteristics of the small bubbles in the liquid slugs have been presented. It has been estimated on the results that the axial pitch is longer than the radial pitch, namely the small bubbles do not distribute isotropically.