Effect of Aerated Pore Distribution on Bubble Plume Movement in a Cylindrical Aerated Tank

Abstract

Aeration is crucial for biological wastewater treatment process but energy intensive. Aerated pore distribution in an aeration tank can control oxygen transfer and energy consumption. Therefore, this study aimed at elucidating the fundamental flow structure of gas phase in bubble plumes in a cylindrical tank with different aerated pore distance (ranged from 0.03-0.09m). Both experiments and numerical simulation were used. PIV (Particle Image velocimetry) technology was used for getting bubble phase flow field. Bubble population behavior model (BPBM) coupled with computational fluid dynamics (CFD) was established for numerical simulation. Results showed that aeration distances greatly affected the movement of gas-phase. When the aeration distances were large or small, the attractive interaction generated by air columns in different aeration pore caused a turbulence of bubble plume. At the meanwhile, a large of bubbles separated from the main air columns, which resulted in an unsteady gas-phase structure. The structure of bubble plume was relatively stable with an aerator spacing of 0.0625m in this study, which was beneficial for the connection between gas-phase and liquid-phase.