The Master Thesis entitled „Hydrodynamics and Transport Phenomena within Osmotic Membrane Modules – A Modeling Approach by Use of COMSOL Multiphysics™” evaluates the complex hydrodynamic and solute transport mechanisms in spiral wound membrane modules. Results indicates that the feed spacers are responsible for the disruption of the hydrodynamic boundary layer. Unsteady / turbulent flow conditions don´t have an additional significant effect on the concentration polarization on the membrane surface but do have a significant higher pressure drop effect. The Thesis is presenting a novel feed spacer measuring method by using computer-tomography (CT) as a new standard method for membrane simulations. The CT approach is offering new possibilities to develop improved spacer geometries with optimized hydrodynamic and anti-fouling properties. The thesis project was advised by Nils Horstmeyer and Prof. Jörg Drewes.