Experimentelle Untersuchung von Plattform-Kühlung in einer gekrümmten Leitschaufel-Kaskade

Effective cooling of highly loaded turbine endwalls can be supplemented by utilizing design-
related gaps between turbine parts for coolant injection. When dimensioning the secondary air
system, it is essential to have an understanding of how large the contribution to platform cooling
is depending on geometric and flow-related parameters. To account for the influence of the radial
pressure gradient on secondary flow and thus on film cooling performance, an annular sector
cascade has been developed and integrated into the high-speed turbine test rig at the Institute
of Fluid Machinery and Fluid Dynamics (SAM) of the University of Kaiserslautern-Landau. The
cascade features four state-of-the-art nozzle guide vanes with axisymmetrically contoured
endwalls. An exchangeable insert allows different upstream slot geometries to be investigated.
In addition, the setup can be used to investigate classic film cooling holes upstream of the
leading edge. The test bench incorporates various measurement techniques such as five-hole
probes, pressure sensitive paint and infrared thermography to investigate both thermal and
aerodynamic aspects of film cooling