用CFD方法模拟膜生物反应器内部流场及布气优化

采用Eulerian多相流模型对膜生物反应器进行气液两相流数值模拟,对“对齐”和“对齐导流”两种反应器构型内部流场气含率、速度场和膜面液体流速进行了分析比较,并就布气方式进行了分析和优化,同时借助缩小实验模型对模拟结果进行了实验验证.结果表明：两种反应器构型流场内的气泡呈现出汇集于膜组件中心位置,然后在膜组件顶端散开的流动状态;导流作用对反应器内气含率分布的影响不大,但对速度场分布特性影响显著;体积缩小100倍的对齐导流模拟装置中的气液流动状态与CFD模拟结果基本一致;通过对布气方式的优化模拟发现,不均匀布气方式可以改善气体分布状况,提高反应器内气含率和流场的湍流强度.

CFD Simulation and Optimization of Internal Hydrodynamic Characteristics and Aerating Distribution in Membrane Bioreactor

The simulation of Eulerian multiphase flow model with two-phase （air ~ water） in membrane bioreactor were aimed at obtaining and comparing gas hold-up distribution, velocity field and membrane surface rate among the two reactor internal configuration of ＂alignment＂ and ＂alignment＂ diversion. Furthermore, the gas distribution mode was analyzed as well as optimized. The mini-model experiment was conducted to validate the simulation result. It is shown that. the bubbles track of internal field tended to flow to the membrane assembly center position, and then dispersed on the top of membrane modules in the two reactor configurations; the influence of diversion on gas holdup distribution was in apparent while notable on the velocity field distribution. The simulation results of an experimental model shrunk 100 times was proved to be consistent with the experimental results. Through an optimization simulation of gas distribution mode, the non-uniform gas distribution mode was proved that it can improve the range of gas distribution and the turbulence intensity.