LARGE EDDY SIMULATION OF FILM COOLING FLOW ABOVE A FLAT PLATE FROM INCLINED CYLINDRICAL HOLES

摘要

Large Eddy Simulation of a realistic film cooling configuration is performed, consisting of a large plenum feeding a periodic array of short film cooling holes with length to diameter ratio L/d = 3.5. Film cooling jets are issued at 35 degrees into the turbulent crossflow boundary layer above the flat surface. Time-averaged flowfield is analyzed to reveal steady and unsteady structures occurring as a result of plenum-jet-crossflow interactions. Among these structures are the flow separation inside the film-hole, reverse flow zone right behind the jet injection and the counter-rotating vortex pair in the wake of the jet. All of these structures influence the wall temperature distribution and have a negative effect on film cooling effectiveness.