On the use of LES in the Aero-Thermal Analysis of Internal Cooling Systems

Recent developments in cooling systems play a critical role in increasing the thermal efficiency and power output of gas turbines. Pin fin arrays, in particular, are used to improve vane reliability near trailing edge. The optimum shape and spacing of such elements are usually determined experimentally, or more recently, by using CFD. The problem has been investigated by Ames et al. by means of an experimental campaign. From the numerical point of view, the main constrains of CFD when studying such massively unsteady flow is related to the high computational cost. The main aim of this work is a critical investigation of the test-case by means of different turbulence closures. Reynolds-Averaged Navier-Stokes, Unsteady RANS and Large Eddy Simulation have been conducted on the same LES-able computational grid, in order to highlight the influence of the different approaches, neglecting the uncertainty sources provided by the discretization process.