LIQUID FLOW IN IMPELLER SWEPT REGIONS OF BAFFLED AND UNBAFFLED VESSELS WITH A TURBINE-TYPE AGITATOR

Liquid flow in the impeller swept region of vessels with a turbine-type agitator was examined for the flow path between the neighboring blades of the rotating impeller. Visualization of the flow and its measurement were done using particle tracking velocimetry with a camera rotating along with the impeller. Internal liquid flow of the impeller differed when the velocity magnitudes were compared in conditions with and without baffles. Larger circumferential and radial velocities were observed without the baffles and with the baffles, respectively, which was considered to result in the difference of impeller power transmission. Efficiencies produced, based on the flow-head concept, reflected the impeller power characteristics. The turbine-type impeller as an actuator was demonstrated to improve in the flow characteristics with viscous losses increased by the baffles. In terms of impeller efficiencies based on the power consumption, the effect of baffles for the energy was as a decreased transmission and an increased transport.