Gas-liquid flow pattern identification and bubble characteristics analysis in a static mixer based HiPOxTM reactor

The multiphase flow in HiPOxTM reactor are the criteria for the mass transfer of ozone at the gas–liquid interface, determining the degradation rate of the refractory organic pollutant in industrial wastewater. In this work, the gas–liquid flow patterns and their transitions in a static mixer-based HiPOxTM reactor were investigated systematically by a high-speed camera. Six types of flow patterns were identified under the conditions of inlet liquid Re ranging from 8,000 to 160,000 and gas fraction from 3.23% to 86.96%. Three composite flow patterns are involved, and a flow pattern map was demonstrated. The effect of liquid inlet flow rate on the bubble groups is much more significant than that of gas phase in the bubble flow. If the liquid flow rate increases twice, the Sauter mean diameter is expected to fall to 65%, which was only reduced by 28% when the gas flow rate even drops 8 times.