Computational fluid dynamics (CFD) was used to study hydrodynamics and mass transfer in a conventional circular bench-scale membrane testing device, and improved geometry of the device was proposed. The conventional and modified geometries were fabricated for experimental validation of the simulation results. It was observed that the modified cell outperformed the conventional cell in terms of distribution of mass transfer coefficient and shear stress on the membrane surface. Further, the ranges of average shear stress and mass transfer coefficient in the modified membrane testing cell for crossflow rates between 25 and 60 L/h overlaped with the corresponding ranges observed in a spacer-filled membrane channel. Hence, the modified geometry is a better choice for membrane testing and can also be extended to study the performance of antifouling membranes.