Computational modeling for visualization of flow patterns in a membrane testing device

Computational fluid dynamics (CFD) modeling is carried out to examine fluid flow behavior in a novel membrane testing cell. The modeling results in terms of velocity and shear stress distribution show that fluid movement near the membrane surface in the device is mainly in cross flow direction. The region in the center is an exception where the fluid hits the membrane in normal direction after leaving the inner tube. Stagnant flow zones are observed at the outer wall of the cell were local velocities are very low. Flow recirculation regions are also formed around the central tube before the fluid exits the cell. The comparison of various heights of tube shows that an inner tube of greater height is preferred due to better flow patterns and higher magnitudes of wall shear rates.

► At the outer wall of the cell the fluid velocity is lower.
► For the remaining portion the z-velocity is nearly zero showing cross flow movement.
► Fluid leaves the tube, strikes the bottom and causes a major recirculation zone.
► The local minimum value of shear stress exists in the centre.