A comparative study of turbulence models for the flow and heat transfer in a rib-roughened, internal turbine cooling channel

The present contribution focuses on the aero- dynamic predictive capabilities of RANS and LES simulations for internal gas turbine cooling chan- nels. Rib-roughened surfaces are employed for such kind of applications to promote turbulence and to increase the heat transfer between the wall and the coolant. The numerical results for a cooling chan- nel with a blockage ratio of 0.3 and a Reynolds number of 40,000 are compared with experimental data obtained at the Von Karman Insitute for Fluid Dynamics. Different turbulence model approaches have been tested, and their predictive capabilities are evaluated: the results clearly show the inferiority of RANS simulations, both based on the Boussinesq eddy viscosity assumption and on Reynolds-stress modeling, in comparison with the performed Large Eddy Simulations (LES) in predicting the flow beha- vior.