Ensuring an adequate life of high pressure turbines requires efficient cooling methods, such as rim seal flow ejection from the stator-rotor wheel space cavity interface, which prevents hot gas ingress into the rotor disk. The present work addresses the potential to improve the efficiency in transonic turbines at certain rim seal ejection rates. To understand this process a numerical study was carried out combining computational fluid dynamic simulations (CFD) and experiments on a single stage axial test turbine. The three dimensional steady CFD analysis was performed modeling the purge cavity flow ejected downstream of the stator blade row, at three flow regimes, subsonic M2 = 0.73, transonic M2 = 1.12 and supersonic M2 = 1.33. Experimental static pressure measurements were used to calibrate the computational model. The main flow field-purge flow interaction is found to be governed by the vane shock structures at the stator hub. The interaction between the vane shocks at the hub and the purge flow has been studied and quantitatively characterized as function of the purge ejection rate. The ejection of 1% of the core flow from the rim seal cavity leads to an increase of the hub static pressure of approximately 7% at the vane trailing edge. This local reduction of the stator exit Mach number decreases the trailing edge losses in the transonic regime. Finally, a numerically predicted loss breakdown is presented, focusing on the relative importance of the trailing edge losses, boundary layer losses, shock losses and mixing losses, as a function of the purge rate ejected. Contrary to the experience in subsonic turbines, results in a transonic model demonstrate that ejecting purge flow improves the vane efficiency due to the shock structures modification downstream of the stator.
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ASME Turbo Expo 2009: Power for Land, Sea, and Air
June 8–12, 2009
Orlando, Florida, USA
Conference Sponsors:
- International Gas Turbine Institute
ISBN:
978-0-7918-4888-3
PROCEEDINGS PAPER
Investigation of the Flow Field on a Transonic Turbine Nozzle Guide Vane With Rim Seal Cavity Flow Ejection Available to Purchase
M. Pau,
M. Pau
von Karman Institute for Fluid Dynamics, Rhode Saint Gene`se, Belgium
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G. Paniagua
G. Paniagua
von Karman Institute for Fluid Dynamics, Rhode Saint Gene`se, Belgium
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M. Pau
von Karman Institute for Fluid Dynamics, Rhode Saint Gene`se, Belgium
G. Paniagua
von Karman Institute for Fluid Dynamics, Rhode Saint Gene`se, Belgium
Paper No:
GT2009-60155, pp. 1119-1129; 11 pages
Published Online:
February 16, 2010
Citation
Pau, M, & Paniagua, G. "Investigation of the Flow Field on a Transonic Turbine Nozzle Guide Vane With Rim Seal Cavity Flow Ejection." Proceedings of the ASME Turbo Expo 2009: Power for Land, Sea, and Air. Volume 7: Turbomachinery, Parts A and B. Orlando, Florida, USA. June 8–12, 2009. pp. 1119-1129. ASME. https://doi.org/10.1115/GT2009-60155
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