曝气速率对附加微通道湍流促进器SMBR流体动力学性能的影响

从CFD数值模拟和PIV实验两方面研究5种不同曝气速率对附加微通道湍流促进器的浸没式平板膜生物反应器中的流体动力学性能的影响,对膜面上液相流速和剪切力随曝气速率的变化进行了分析。从CFD模拟结果与PIV实验结果均可得出,曝气速率为0.5 m/s时附加微通道湍流促进器的浸没式平板膜生物反应器的流体动力学性能要优于其他曝气率下的流体动力学性能,且速度和膜面剪切力平均偏差率分别为7.49%和14.19%。PIV实验验证了CFD模拟过程中模型和边界条件的合理性。这也表明当曝气与微通道湍流促进器结合在一起,更易于在微通道湍流促进器附近产生旋涡和加强流体的湍流程度,从而有效抑制膜表面滤饼层的形成,减缓浓差极化和减轻膜污染。

Effects of aeration rate on hydrodynamic performance of SMBR equipped with micro-channel turbulence promoters

CFD simulation and PIV experiment are used to investigate hydrodynamic performance of a submerged flat-sheet membrane bioreactor equipped with micro-channel turbulence promoters at different aeration rates. Velocity and wall shear stress were measured. The CFD simulation results and PIV experiment results show that hydrodynamic performance of SMBR at 0.5 m/s is better than those of the others. PIV experiment results are similar to the CFD simulation results with an average error of 7.49% and 14.19%, respectively. This proves that the Euler models are chosen appropriately in the CFD package and the meshes generated have satisfactory quality to give a reliable simulation of realistic hydrodynamics. Compared with a single aeration or micro-channel turbulence promoters, aeration and micro-channel turbulence promoters together can be easier to increase velocity, turbulent kinetic energy and wall shear stress on the membrane surface and produce eddy in the vicinity of micro-channel turbulence promoters which enhance the filtration performance, disrupt the buildup of cake layer, reduce the concentration polarization and mitigate membrane fouling.