Abstract
Various methods are used for the velocity measurement of the gas-liquid two-phase flows, for example, Particle Image Velocimetry (PIV) or Laser Doppler Velocimetry (LDV), and ect. The Ultrasonic Velocity Profile monitor (UVP) has a unique feature that it can obtain an instantaneous velocity profile on a line. However, it has not been so far applied to the measurement of the multiphase flow in circular pipes. In this study, velocity distribution of a liquid film arround a large bubble in stagnant water which seems to be a simple type of gas-liquid two-phase slug flow in a vertical pipe was measured using UVP. It was found that the velocity distribution can be almost approximated by the profile curve of a general falling liquid film, while a liquid film receives the effect of tube wall especially near the nose.
