Predictions of Temperature Redistribution in a Turning Duct and in High-Pressure Turbines

An ability to predict the redistribution of total enthalpy in a turbine is critical to assess heat loads on turbine surfaces and hence, to estimate component life. Here, a finite-volume, Reynolds-Averaged Navier Stokes (RANS) code was used to predict the redistribution of temperature in the 90-degree turning duct of Eckert and Irvine (1957). The duct was modeled as inviscid, laminar, and turbulent flow with both an algebraic and a two-equation model. The algebraic model was that of Baldwin and Lomax (1978), and the two-equation model was the k-ω formulation of Wilcox (1998). The results indicate that the average exit profile from the duct can be accurately modeled by all types of modeling considered, however, the two-dimensional exit distributions of temperature from the duct were most closely matched by the two-equation model. Subsequently, the lessons learned in the turning-duct study were applied to predict the redistribution of enthalpy in both single-stage and two-stage high-pressure turbines. The temperature redistribution within the two turbines considered was modeled with: a one-dimensional empirical code, an inviscid 3D solver as both steady and time-accurate k-ω RANS. The cooling flows were modeled with distributed and local mass-injection. The most consistent accuracy for both turbines was realized with the time-accurate, local mass-injection film-cooling k-ω simulations. The steady k-ω simulations with local mass-injection film cooling predicted normalized temperature profiles nearly as well as the time-accurate simulations.