Session: 35-02 Component/Duct Interaction

Paper Number: 152854

Interaction Between the TVF-LPT Hub Cavity With the Mainflow 

This paper aims to provide insight into the complex interaction between a low-pressure turbine (LPT) hub forward cavity and the main flow after an intermediate turbine duct with turning struts. A turbine vane frame (TVF) serves as a structural link connecting the last high-pressure turbine to the first low-pressure turbine, functioning as a vane row for the latter. In addition to the struts, the examined TVF geometry features one splitter per strut passage.

The investigations were carried out experimentally and numerically. The experiments took place at the transonic test turbine facility (TTTF) of the Institute of turbomachinery and machine dynamics at Graz University of Technology. The two-spool test rig consists of a fully purged, unshrouded high-pressure turbine followed by the TVF and the hub forward purged LPT. Further, the TTTF secondary air system (SAS) can inject tracer gas (CO₂ or N₂O), which can be detected downstream of the seeded cavity by taking samples via a pitot probe. These well-established measurements are presented for two rim seal configurations downstream of the LPT.

Additional insights were drawn from the multiphase URANS simulation of the TVF-LPT component. The domain fluids were split into the main flow fluid and the cavity fluid in order to perform a numerical tracer gas technique, which is validated with the measurements.

Ultimately, the paper explains the circumferentially non-uniform distribution of the LPT hub forward cavity flow caused by the outlet flow of the upstream located strut.

Presenting Author: Nicolas Krajnc Graz Universiy of Technology

Presenting Author Biography: Born and raised in Graz, I studied mechanical engineering at Graz University of Technology (graduated Jul 2020). Since Sep. 2020, I have been working on my PhD at the Institute of Turbomachinery and Machine Dynamics (Graz University of Technology).

Authors:

Nicolas Krajnc Graz Universiy of Technology
Francesco Mangini Graz University of Technology
Asim Hafizovic Graz University of Technology
Wolfgang Sanz Graz University of Technology
Robert Krewinkel Graz University of Technology
Marios Patinios GE Aerospace
Emil Göttlich Graz University of Technology