Numerical investigation of the secondary flow of a transonic turbine stage using various turbulence closures. ASME paper

The accurate numerical simulation of the flow through turbine stages strongly depends on the proper prediction of turbulence phenomena. Especially investigations of heat transfer, skin friction, flow separation and secondary flow effects demand a reliable simulation of the turbulence respectively laminar to turbulent boundary layer transition. This paper presents a steady state three-dimensional numerical investigation of a transonic turbine guide vane at flow conditions similar to modern highly loaded gas turbines. At the Institute for Thermal Turbomachinery and Machine Dynamics extensive experimental investigations of the three dimensional flow trough this turbine stage were done to gain a better understanding of the flow physics and to verify computational results. The applied numerical code, which was developed at the institute, solves the Reynolds-averaged Navier-Stokes equations using a time-iterative finite volume method. Turbulence is modeled with the one equation model of Spalart and Allmaras, the two equation SST k-ω model of Menter and the V2F model of Durbin, the latter model is also able to capture boundary layer transition to turbulence. The objective of this paper is to compare the numerical results with experimental data and to figure out the impact of the different turbulence models on secondary flow effects