Analysis of Micromixers on Reverse Osmosis Based Desalination Membranes

Abstract Corrugated membranes are used in desalination modules to improve membrane performance. In this study, in order to gain a deeper insight into the separation performance of these corrugated membranes, a computational fluid dynamics simulation was carried out for a proposed three-dimensional desalination modules containing triangular and square ribs attached to the membrane surface. Solution-diffusion membrane transport model, based on coupling water permeation rate with local salt concentration, was applied for membrane boundary condition involving selective removal of components in the feed channel. The local water flux, salt concentration, shear stress, and Sherwood number were monitored over the membrane surface to determine the effect of eddy promoter corrugations on high salt concentration mitigation and total water flux for Reynolds number of 100, 400 and 1000. Mathematical model and numerical methods employed are validated by comparing predictions against measurements reported earlier. The results show that corrugated membranes especially triangular chevrons enhance membrane performance profoundly at all flow rates. Water permeation rate is increased, concentration polarization is alleviated, and the potential fouling in the module is reduced by introducing corrugated membranes. Membrane performance enhancement is greater at higher flow rate.