Impact of Film-Cooling Jets on Turbine Aerodynamic Losses

Abstract

This paper documents a computational investigation of the aerodynamic impact of film cooling on a linear turbine airfoil cascade. The simulations were for single row injection on both the pressure and suction surfaces, downstream of the leading edge region. The cases match experimental efforts previously documented in the open literature. Results were obtained for density ratio equal to 1.0 and 2.0, and a blowing ratio range from 0.91 to 6.6. The domain included the passage flow as well as the film hole and blade interior. The simulation used a dense, high-quality, unstructured hybrid-topology grid, comprised of hexahedra, tetrahedra, prisms, and pyramids. The processing was performed with a pressure-correction solution procedure and a second-order discretization scheme. Turbulence closure was obtained using standard, RNG, and “realizable” k-ε models, as well as a Reynolds stress model. Results were compared to experimental data in terms of total pressure loss downstream of the blade row. Flow mechanisms responsible for the variation of aerodynamic losses due to suction and pressure surface coolant injection are documented. The results demonstrate that computational methods can be used to predict losses accurately on film-cooled airfoils. [S0889-504X(00)01503-8]