Investigations Of The Instability For Two-phase Slug Flow Under Rolling State

In this paper, the characteristics of two-phase slug flow movement in stagnant water and flowing water, in vertical pipe and under rolling state were studied.First, the velocity of Taylor bubble in different gas and water flow rate condition was measured by electrical conductivity probe designed independently. By comparing with experiment data and the empirical formula, it shows that the designed probes can measure the Taylor bubble velocity well in stagnant water or flowing water in vertical pipe.Secondly, the movement of Taylor bubble under vertical, incline, and rolling state was simulated by using the FLUENT VOF method. A method abstracting Taylor bubble wake length from the simulation result data was designed. The minimum steady length between two consecutive Taylor bubbles in stagnant water in vertical pipe, in incline pipe and under rolling state was determined by analyzing the wake length of Taylor bubble.The results indicate that the minimum steady distance between two consecutive Taylor bubble in stagnant water in vertical pipe is 6D; the minimum steady distance between two consecutive Taylor bubble in stagnant water in incline pipe, the angle between the pipe and vertical direction is 20 degrees, is 12D; While under rolling state, the minimum steady distance between two consecutive Taylor bubble in stagnant water decline with the increase of rolling frequency, as which the maximum rolling angle is 20°, the period is 10s, is 24D; the maximum rolling angle is 20°, the period is 6s, is 14D; the maximum rolling angle is 30°, the period is 6s, is 19D.