Modeling of concentration polarization in a reverse osmosis channel with parabolic crossflow

Concentration polarization in narrow reverse osmosis channels with parabolic crossflow was numerically simulated with finite different equations related to permeate velocity, crossflow velocity, average salt concentration, and wall salt concentration. A significant new theoretical development was the determination of two correction functions, F₂ and F₃, in the governing equation for average salt concentration. Simulations of concentration polarization under various conditions were then presented to describe the features of the new model as well as discussions about the differences of concentration polarizations of the more realistic parabolic flow with those when plug flow or shear flow was assumed. The situations in which the simpler models based on shear or plug flow can be used were indicated. Concentration polarization was also simulated for various conditions to show the applicability of the model and general features of concentration polarization in a narrow, long reverse osmosis channel.