Application of transition modelling in CFD for use with turbine blades

Abstract

The design of internally-cooled gas turbine blades requires accurate predictions of distributions of blade temperature values and temperature gradients. This requires accurate predictions of heat transfer distributions from the hot gas (on the blade external surfaces) and the coolant (on the blade internal cooling passage surfaces). Navier-Stokes solvers assume the flow to be either fully laminar or fully turbulent, and solve accordingly. Four turbulence modelling options have been tested as part of this study. In general it was found the following observations held true. Pressure surface heat transfer was acceptably well predicted by all turbulence models, including the boundary layer solver. On the suction surface accuracy of prediction was best achieved by the addition of the transition model (as in the boundary layer and Spalart-Allmaras with transition) compared to those without (Yang-shih k-e and Spalart-Allmaras without transition).