Performance improvement of Riblets in a Turbine Center Frame and their material development for high temperature environments

The effects of using microstructures (riblets) on the surface of strut, hub and shroud of a turbine center frame (TCF) are experimentally investigated. Riblets are streamwise grooved surfaces which reduce the viscous drag in turbulent boundary layers. The present work gives a closer insight into the application and measurement results of riblets on a TCF strut, hub and shroud. The change in the flow behavior and reduction in total pressure loss was investigated in the cold flow test facility TTTF at TU Graz representing a turbofan engine setup containing a high-pressure stage with TCF and low-pressure turbine nozzle. Additionally, material development for the application of riblets in hot flow environments of experimental turbines is presented as part of an ongoing research project.