Heat-and-Mass Transfer Relationship to Determine Shear Stress in Tubular Membrane Systems

The main drawback of Membrane Bioreactors (MBRs) is the fouling of the membrane. One way to reduce this fouling is through controlling the hydrodynamics of the two-phase slug flow near the membrane surface. It has been proven in literature that the slug flow pattern has a higher scouring effect to remove particulates due to the high shear rates and high mass transfer between the membrane surface and the bulk region. However, to calculate the mass transfer coefficient in an efficient and accurate way is not straightforward. Indeed, for accurate determination, numerous complex experimental measurements are required. Therefore, this work proposes an alternative method that uses already existing heat transfer relationships for two phase flow and links them through a dimensionless number to the mass transfer coefficient (Sherwood number) to obtain an empirical relationship which can be used to determine the shear stress.