ROLE OF BUBBLE BEHAVIOR IN TURBULENCE STRUCTURE OF VERTICAL BUBBLY FLOW-SIMULTANEOUS MEASUREMENT OF BUBBLE SIZE, BUBBLE VELOCITY AND LIQUID VELOCITY USING PHASE DOPPLER METHOD

The microscopic flow structure in air-water bubbly mixtures flowing through a vertical square duct was experimentally investigated by laser Doppler measurements. Local velocities of liquid and bubbles as well as bubble size were simultaneously measured using a phase Doppler velocimeter system. It was found as a result that a zig-zag motion of the bubble plays an important role in the momentum transfer of liquid flow in the direction perpendicular to the tube axis.