An experimental study on turbulent swirling water flow with immiscible droplets

Measurements have been carried out for the turbulent swirling water flow with low-density immiscible silicon-oil droplets in a horizontal pipe. An impeller fixed inside the pipe generates the swirl, which is stronger than that in our previous study. The flow is visualized with fluorescent tracer particles, which are captured with video cameras from the side and downstream end of the pipe. The instantaneous velocity field is obtained from the captured images with the particle tracking velocimetry method. The results indicate that the size and motion of the droplets depends on the buoyancy force, lift force, pressure-gradient force and drag force. It is considered that the increase in the turbulence intensity is due to the wake flow of the droplets. (C) 2006 Elsevier Inc. All rights reserved.