Corrosion processes are dependent on the ambient conditions which may vary locally on a single part or an assembly of several parts, for example temperatures, wet and dry conditions, etc. Especially, local film thickness of fluid films originating from sprays or condensation processes lead to different conditions for the complex mechanisms of corrosion. The fluid may be a composition of different salts, acids, etc. which may deposit on the surfaces of the parts resp. deposited salt will be dissolved. This short and incomplete list shows only a few of the challenges in the modelling of these processes which are coupled and cannot be treated isolated. For the prediction of corrosion processes, a coupled model to describe the conjugate heat transfer between the gas phase, the fluid film and the solid part has been developed using the framework of the open source CFD code OpenFOAM®. The different kinds of salts are implemented by a novel approach splitting up the salts in single ions according to their stoichiometry. The transport of the different ions is modelled with differential transport equations allowing to form different kinds of deposits or dissolution based on solubility and stoichiometry. Based on ion concentration, film thickness, etc. empirical models developed from experimental data provide the mass reduction of the solid. This framework is used to simulation real transient cyclic corrosion test (CCT) based on virtual prototypes. As the time scales of the underlying processes, like film dynamics, and the overall length of the test cycle are very different, several assumptions have been considered to simulate real test cycles in reasonable time scales. The model has been tested for a simplified test case which is based on a U-steel and a complex CCT. The results show a good agreement with experimental data and confirm the assumptions made.