Measurement of Turbulent Flow Fields in a Stirred Vessel with Four Baffles by Laser-Doppler Velocimetry : Analysis with Periodic Averaged Velocity Profiles

Abstract

The 3-D flow field relative to a rotating paddle blade is obtained by synchronizing LDV measurements with the output of a shaft-mounted encoder, thus making it possible to determine the impeller stream velocity field, including details of the discharge flow region behind the blades. Mean velocities, ensemble-averaged between a specific impeller blade pair(over 90°)show the extent determinde from both the passage and structure of the discharge flow region. Pumping capacities are consequence of fluid entrainment into the discharge flow region. Mean velocities taken in a rotating frame of reference reveal a significant periodic variation near to those taken in a fixed frame.