MBR单根中空纤维膜丝的CFD模拟仿真与研究

CFD Simulation and Research of MBR Single Hollow Fiber Membrane

摘要: 在对MBR膜生物反应器的模拟仿真中，我们曾使用计算流体动力学(CFD)的相关软件建立MBR中空纤维膜的二维模型，并成功模拟出流体在中空纤维膜区域的流动现象。为了后期提高中空纤维膜的模拟效果，我们可以考虑先将单根中空纤维膜丝放进膜组件中，并建立三维模型进行模拟，计算和观察，为扩展到多根中空纤维膜丝的研究做好前期的工作。在模拟中，由于中空纤维膜管壁小孔的数量规模达十亿数量级，在建模阶段画出大量的小孔并不现实。所以，在模拟时，我们引入多孔介质的思想，将中空纤维膜的管壁定义为多孔介质区域，从而完成对中空纤维膜管壁小孔的模拟。在之后进行的CFD数值求解的计算中，我们采用比较精确的有限体积法求解离散方程，经迭代100次后，我们可以从残差曲线图中看到所有值均低于阈值，呈收敛状态。模拟结果表明，通过CFD相关软件对单根中空纤维膜丝的模拟[1]，基本符合流体的实际流动现象。

Abstract: By simulation analysis in MBR membrane bioreactors research, we have used computational fluid dynamics (CFD) related software to create a two-dimensional model and simulated the flow of fluid in the hollow fiber membrane. In order to improve the simulation effect and enhance precision in calculation, we can consider firstly putting a single fiber into the membrane module and establish a three-dimensional model for simulation, so as to do a good job for the study of the expansion of the 3000 hollow fiber membrane. It is not realistic to draw large numbers of holes in a simulation because the number of small holes in the hollow fiber membrane is the orders of magnitude of billion. Therefore, we use model of porous media to define the wall of hollow fiber membrane as a porous zone. In calculating the numerical solution of CFD, we use the more exact finite volume method (FVM) to solve the discrete equations. After 100 iterations, we can see from the residuals curve that all values are below the threshold and converge. The result shows that the simulation of single hollow fiber membrane by CFD software [1] is basically consistent with the actual flow phenomenon of the fluid.