Visual Observation of Flow Regime Transition in Downward Vertical Gas-Liquid Flow Using Simple Mixer

Different flow patterns of downward gas-liquid two-phaseflow using simple mixer are studied in an experimental manner. An experimental setup is designed and fabricated to allow the visual observation of downward two-phase flow patterns and their transitions. The flow patterns are recorded by a 1200 frames per second high speed video camera. The quality of downward two-phase flow patterns photos are improved through image processing. The setup includes a transparent vertical pipe of 50 mm diameter and the (L/d) aspect ratio of 80. Flow patterns are obtained through 374 test cases during which air and water superficial velocities changed. In order to assess the performance of the mixer, all expected flow patterns are obtained. The four observed flow regimes are: of falling film, bubbly, slug and froth. The flow map is plotted and transitions among different flow patterns are compared with previous finding in specified conditions indicating a good agreement was observed.