A numerical simulation of the Jülich F-design Solid Oxide Fuel Cells stack is conducted by means of an original mathematical model. The model is implemented in the open source toolbox, OpenFOAM. This cell/stack level model is a key component of a programme to develop a fully integrated multi-scale fuel cell modelling capability, from nano-scale through to system level. It is intended to share the resulting software with other parties openly. Substantial experimental data is available for the Jülich F-design; Stack configuration, flow conditions, interconnector geometries and porous electrode properties prescribed in the numerical model are based on field experiments. The numerical model generates distributions of fluid flow, species concentrations, current density and temperature. The results of the simulations are compared against experimental data obtained from short stacks.