The CAD model was uploaded in STEP format and meshed using the automated tetrahedralization method. The CAD model was provided by Ian. The mesh is quite coarse within the fins but for this kind of analysis this should be sufficient. A finer mesh resolution could be achieved when using the parametrized tet-meshing operation.
The simulation was set up using the steady-state heat transfer analysis type. On the bottom of the heat sink a constant temperature of 70°C is applied while a convection boundary condition of 5 W/(m^2 K) is applied to the rest of the surfaces, especially the fins.
The simulation has been carried out on a 2-core machine which took around 6 minutes. The solution field in the figure above shows the temperature field within the heat sink.