Computational fluid dynamics membrane modules

The computational fluid dynamics (CFD) module of COMSOL 4.0 multiphysics was employed to model the oxygen flow through PMMA—PMMA nanofiber mat sandwich films. The Darcy s law interface under the porous media and subsurface flow branch can be used to model low-velocity flows, for which the primary driving force is the pressure gradient across the membrane, and the fluid is mostly influenced by the frictional resistance within the pores. 

The unexpected results of Sablani et al. [17] (i.e., less turbulence with smaller spacer thickness) may be best explained by an excellent paper by Schwinge et al. [82], The latter employed computational fluid dynamics (CFD) in a study of unsteady flow in narrow spacer-filled channels for spiral-wound membrane modules. The flow patterns were visualized for different filament configurations incorporating variations in mesh length and filament diameter and for channel Reynolds numbers, Re y, up to 1000. The simulated flow patterns revealed the dependence of the formation of... 

The rational design and optintization of efficient and effective membrane modules will likely rely on advanced computational fluid dynamic (CFD) approaches. For example, we have begun to employ CTD tools in the development of simple modules and have Olustiated that module efficiencies can increase by about 100% simply by increasing the baffle density. However, for membrane technology to rapidly move from the laboratory to the field, considerable additional attention needs to be given to module design. 

Fouling deposition in crossflow membrane filtration can be indicated by the deceleration of particles on the membrane surface. PIV was used to identify early fouling phenomena (particle decelerations) and the dead zone during membrane filtration [84]. PIV has the same limitation as other optical methods, like DOTM, as it requires optically transparent solutions. However, how this technique can be extended to real module with a large number of fibers is a challenge and it may be limited to laboratory validation of bubbling and computational fluid dynamic models of MBR systems. 

---