Experimentally investigating bubble dynamics and pressure drop for bubbly upflow in a vertical annular channel

Abstract This paper experimentally investigates the bubble characteristics for a bubbly upflow in an annular channel using two-sensor probes and the high-speed camera. The measured parameters include the radial distributions of void fraction, interfacial area concentration, and bubble size. The present measured results are also compared with those from the previous work, confirming the reasonability of present data for the bubbly flow. A simplified two-phase frictional pressure-drop model is proposed to estimate the frictional pressure-drop across the annular channel for the bubbly upflow. Based on comparison with the measured data, the deviation in the two-phase frictional pressure-drop predicted by this simplified model is within 40%. In addition to providing the understanding of bubble dynamics in an annular geometry, the present measured data can also help develop and assess the CFD two-phase model.