Region coupling is an interesting approach to combine different solvers in complex multiphysics problems. It is usually employed to couple the temperature between solids and fluids. In order to simulate a porous medium in a fluid flow it is necessary to couple temperature, pressure, species concentration and velocity of a fluid and a two-phase fluid. Such a coupling was implemented in OpenFoam® 7 based on the loose coupling approach. In order to achieve a high quality of the loose coupling the influence of grid size and number of solver iterations were investigated. The coupled approach is shown to perform better with increasing system sizes than a pure two‑fluid simulation. However, its accuracy depends on additional iterations for the coupling.