Numerical study of BSA ultrafiltration in the limiting flux regime — Effect of variable physical properties

Ultrafiltration of BSA solutions in a parallel cell was studied by numerical methods taking into account concentration dependent properties. The Navier–Stokes equations, in the stream function–vorticity formulation, and the mass transport equation were solved simultaneously. The numerical code was validated by comparison with data from benchmark analytical solutions. The flow and concentration fields in the limiting flux regime were studied in detail and compared with the fields for constant properties. Numerical results were also compared with experimental data of the permeate velocity in the limiting flux regime published in the literature. This comparison shows that the concentration dependence of the viscosity, diffusivity and osmotic pressure are all necessary to explain experimental results published in the literature.