Research on dynamics characteristics of flow field in MBR by PIV technology
膜生物反应器内流场动力学特性的PIV实验研究

The dynamic characteristic of gas-liquid two phase flow around membrane fibers have important effects on controlling concentration polarization and membrane pollution in submerged membrane bioreactor system. Particle image velocimetry (PIV) technology was used to measure the dynamic characteristic of liquid phase flow around membrane fibers. First, the gas-liquid two phase flow field image was gained by PIV technology, gray resolution method was developed and implemented to discriminate liquid phase velocity field from two phase flow field image, and vorticity field data of liquid flow was calculated around membrane fibers by Tecplot. We analyzed the liquid phase flow field and calculated vorticity field data around membrane fibers under the condition of aeration intensity of 2.5,3.0,3.5,4.5,5.5 and 6.5 m3/h in bore diameter of 3 mm.It was shown that aeration intensity affected liquid phase flow field and vorticity field greatly, increasing aeration intensity in a certain range can make the liquid velocity and vorticity increase. Under the experimental conditions, the optimal aeration intensity identified as 6.5 m3/h. At the same time, we also analyzed dynamics characteristics of bubble with bore diameter of 3 mm. The study provides experimental data and research experience for optimization design of membrane bio-reactor (MBR).