Session: 35-02 Turbine Transition Ducts

Paper Number: 126664

126664 - Redistribution of Purged Cavity Air Inside a Turbine Exit Vane Frame due to the Interaction With the Main Airflow 

As a consequence of enhanced pressure ratios and combustion exit temperatures for higher jet engine efficiencies, the exit temperature of the Low Pressure Turbine (LPT) increases, too. To prevent hot gas from entering the slot cavity between the LPT’s last stage rotor and the Turbine Exit Vane Frame (TEVF), purge air is extracted from the upstream compressor and ingested through the cavity.
The present work investigates the spatial redistribution of purged cavity air inside a Turbine Exit Vane cascade due to its Interaction with the main air flow. For this purpose, experimental investigations have been conducted using aerodynamic 5-hole pressure probes and the CO2 seed gas technique. Furthermore, numeric results yield better insights into the flow`s characteristics. The investigations concludes three different engine-relevant operating conditions.
In dependence on the vane geometry, different ingress and egress at the cavity exit can be observed. This Interaction of the main flow with the rim seal cavity strongly determines the flow path of the purge fluid throughout the TEGV passage. It is shown that purge air migrates against the cross-flow pressure gradient as it flows through the cascade. Depending on the operating condition and with respect to the vane’s lean, different radial migration and mixing of the purge fluid is observed.

Presenting Author: Malte Schien Institute of Thermal Turbomachinery and Machine Dynamics

Presenting Author Biography: In 2021 Mr. Schien finalized his studies in mechanical engineering. In the following, Mr. Schien began to work as a PhD Student at the Institute of Thermal Turbomachinery and Machine Dynamics of Graz University of Technology. His research focuses on ducts, especially on the turbine rear frames and their interaction with purged cavity fluid.

Authors:

Malte Schien Institute of Thermal Turbomachinery and Machine Dynamics
Pablo Lopez GE Aerospace
Lukas Bratusek Institute of Thermal Turbomachinery and Machine Dynamics, TU Graz
Franz Heitmeir Institute of Thermal Turbomachinery and Machine Dynamics, TU Graz
Andreas Marn Institute of Thermal Turbomachinery and Machine Dynamics, TU Graz