The master thesis of David Roos Launchbury deals with the implementation and validation of a numerical solver for incompressible large eddy simulation (LES) with heat transfer in OpenFOAM. Academic and industrial cases, ranging from flow between parallel plates to film cooling, are investigated utilising existing and newly-implemented turbulence models. Simulations using no turbulence models, i.e. under-resolved DNS (UDNS) simulations, are performed for comparison. Very good results are obtained in all cases with variations among the individual models, with the UDNS simulations performing surprisingly well. The study shows that the developed software is able to simulate complex cases reliably and accurately.