Computational fluid dynamics simulation of Liqui-Cel membrane using OpenFOAM: implication for membrane distillation

We investigate fluid dynamic behavior inside Liqui-Cel membrane contactors using open-sourced OpenFOAM, which provides solvers for computational fluid dynamics (CFD) software. A mesh was generated using NETGEN and converted to OpenFOAM format. In OpenFOAM, icoFoam (a solver for a transient, laminar flow of a Newtonian fluid) was used to calculate flow and pressure profiles inside the Liqui-Cel module. The inlet part of the Liqui-Cel module seems to undergo strong stress due to rapid change in feed flow direction. Feed flow tangent to pre-installed hollow fibers is rapidly developed from the inlet region to middle baffle. Rotating flow in the azimuthal direction was shortly observed from the baffle to the module outlet. Numerical simulations of Liqui-Cel CFD seem to be very challenging due to the large fiber number of hollow fibers. For fast simulation, the interior of the Liqui-Cel module can be viewed as anisotropic porous media, and transmembrane mass flux can be calculated as a perturbation of the tangential shell flow. Potential of using Liqui-Cel module for membrane distillation is discussed.