基于PIV技术的ABR反应器在不同HRT下的液相流态特性

利用激光粒子图像测速技术（PIV）对ABR反应器的液相流态进行了研究，在水力停留时间（HRT）为3~58 h变化时，测试得反应器内下流室和上流室折流板内外侧关键截面的流场数据，获得了相关流场特征，包括速度矢量图、流线图谱和涡量场等。结果表明，HRT对下流室和上流室的液相轴向、径向平均速度和平均涡量强度影响不同，液相回流面积随HRT的增加逐渐减小；下流室液相平均涡量强度随HRT的增加逐渐增加；上流室液相平均涡量强度随HRT的增加逐渐减小。下流室和上流室在特定HRT时产生涡流、沟流。在本实验条件下，当处理难降解或高浓度废水时，得出HRT为33 h时反应器整体流态最佳。

Dynamics characteristics of flow field in ABR based on PIV technology in different HRT

When the hydraulic retention time (HRT) was 3 to 58 h, the flow field data for the inner-and outer-side critical sections of the down-flow chamber and the up-flow chamber baffle plate in the ABR reactor were measured by particle image velocimetry (PIV).Related flow field characteristics, including velocity vector diagrams, streamline patterns, and vorticity distributions, were obtained through correlation analysis.The results showed that the effects of HRT on the axial and radial mean velocities and the mean vorticity intensity of the liquid phase in the down-flow and the up-flow chambers were different.As HRT increased, the mean vorticity intensity of the liquid phase in the down-flow chamber of the reactor increased gradually.The recirculation area of the liquid decreased as the HRT increased.With the increase in HRT, the mean eddy intensity of the liquid phase in the reactor gradually decreased.The up-flow and down-flow chambers produced a vortex flow and channel flow at specific HRTs.When the treatment process included difficult-to-degrade or highly concentrated wastewater, under the experimental conditions, the overall flow pattern of the reactor was best when the HRT was 33 h.