Research on the Flow Pattern of Bubble Plume in an Aeration Tank

摘要

The flow pattern of gas-liquid two-phase flow in an aeration tank is of critical effect upon mass transfer by the convection. Bubble plume provides unsteadily fluctuating two-phase flow during the aeration. This paper the study on the unsteady structure of bubble plume is dealt with from experiment. The time-serial bubble plume images of different cases in tank have been analyzed. The RCCPIV has been employed to calculate the velocities in those cases, and then the time-serial vortex, the total turbulence intensity, the time-serial streamline are obtained. It has been shown that the aspect ratio and void fraction are the dominant factors influencing the unsteady structure of bubble plume. When the aspect ratio is unity and the void fraction gets higher, the bubble plume has symmetrical vortex structure and longest residence time, which is beneficial for optimizing the aeration system and enhancing the applied range of bubble plume.