Liquid holdup distribution and disturbance wave parameters in air-water horizontal annular flow

Abstract

Annular flow is one of the important flow regimes commonly found in process, power plant, geothermal, nuclear, airconditioning, and other industries employing two-phase flow. It is characterized by liquid film flowing on the wall and a gascore containing liquid droplets. Liquid holdup and disturbance wave are key parameters in such flow. Therefore, it is useful toobserve its behavior for analyzing other parameters in horizontal annular flow.The liquid holdup and wave parameters of horizontal air-water annular flow in 26 and 16-mm-diameter pipe were determinedusing two flush-mounted CECM sensors, spaced 215 mm apart. The air and water superficial velocities were varied from 12 to40 m/s and 0.05 to 0.2 m/s, respectively, and its effects were observed. The common phenomena of annular flow such as thedisturbance wave, ripple wave, wave velocity, wave number, wave coalescence, and wave deformation could be observed. Themean liquid holdup was in the range of 0.04 to 0.15, indicating the gas dominant flow. It is also found that wave velocityincrease as the air and water superficial velocity increase. Similar to those of wave velocity, the wave number also increaseswhen the air and water superficial velocity increase.