The effect of suction velocity on concentration polarization in microfiltration membranes under turbulent flow conditions

The increase in mass transfer coefficient with increase in suction volume flux was successfully quantified. Two virus strains Qβ and MS2 were filtered with a 0.1 μm pore size tubular membrane made out of Al2O3 in the crossflow mode. The rejection results were obtained for various permeation velocities and at different crossflow velocities in the turbulent flow region. The mass transfer coefficient obtained from the experimental results using the velocity variation (VV) method showed an increase in mass transfer with increasing volume flux rate. The mass transfer values calculated based on the Deissler equation which is based on Sherwood number (Sh) correlation did not account for this variation of flux but gave a constant mass transfer rate for the entire flux range. Hence, based on the suction effect on boundary layer, a modification was proposed to the Deissler equation for the calculation of mass transfer coefficient. The mass transfer coefficients obtained with the modified Deissler equation showed a good agreement with the experimentally obtained mass transfer values.