This paper investigates the influence of stator-rotor interaction on the stage performance of three blade tip geometries. A reference flat tip is used to assess two different recess blade geometries. The study is made in the context of the realistic turbine stage configuration provided by the ETHZ 1.5-stage LISA turbine research facility. This numerical investigation describes the details of unsteady recess cavity flow structure and confirms the beneficial effects of the improved recess geometry over the flat tip and the nominal recess design both in terms of stage efficiency and tip heat load. The tip flow field obtained from the improved recess design combines the advantages of a nominal recess design (aerodynamic sealing) and the flat tip configuration. The turbine stage capacity is almost unchanged between the flat tip and the improved recess tip cases, which simplifies the design procedure when using the improved recess design. The overall heat load in the improved recess case is reduced by 26% compared with the flat tip and by 14% compared with the nominal recess. A key finding of this study is the difference in effects of the upstream stator wake on the recess cavity flow. Where cavity flow in the nominal design is only moderately influenced, the improved recess cavity flow shows enhanced flow unsteadiness. The tip Nusselt number from a purely steady-state prediction in the nominal recess case is nearly identical to the time-average prediction. The improved design shows a 6% difference between steady-state and time-average tip Nusselt number. This is due to the strong influence of the wake passing on the recess cavity flow. In fact, the wake enhances a small flow difference at the leading edge of the recess cavity between the nominal and improved recess cavities, which results in a completely different flow field further downstream in the recess cavity.
Skip Nav Destination
Article navigation
January 2011
Research Papers
Influence of Stator-Rotor Interaction on the Aerothermal Performance of Recess Blade Tips
Bob Mischo,
Bob Mischo
Department of Mechanical and Process Engineering, LSM, Turbomachinery Laboratory, Laboratory for Energy Conversion, IET
ETH Zürich
, Sonneggstrasse 3, CH-8092 Zürich, Switzerland
Search for other works by this author on:
André Burdet,
André Burdet
Gas Turbine Business,
Alstom (Switzerland) Ltd.
, CH-5401 Baden, Switzerland
Search for other works by this author on:
Reza S. Abhari
Reza S. Abhari
Department of Mechanical and Process Engineering, LSM, Turbomachinery Laboratory, Laboratory for Energy Conversion, IET
ETH Zürich
, Sonneggstrasse 3, CH-8092 Zürich, Switzerland
Search for other works by this author on:
Bob Mischo
Department of Mechanical and Process Engineering, LSM, Turbomachinery Laboratory, Laboratory for Energy Conversion, IET
ETH Zürich
, Sonneggstrasse 3, CH-8092 Zürich, Switzerland
André Burdet
Gas Turbine Business,
Alstom (Switzerland) Ltd.
, CH-5401 Baden, Switzerland
Reza S. Abhari
Department of Mechanical and Process Engineering, LSM, Turbomachinery Laboratory, Laboratory for Energy Conversion, IET
ETH Zürich
, Sonneggstrasse 3, CH-8092 Zürich, SwitzerlandJ. Turbomach. Jan 2011, 133(1): 011023 (11 pages)
Published Online: September 24, 2010
Article history
Received:
June 28, 2008
Revised:
September 19, 2009
Online:
September 24, 2010
Published:
September 24, 2010
Citation
Mischo, B., Burdet, A., and Abhari, R. S. (September 24, 2010). "Influence of Stator-Rotor Interaction on the Aerothermal Performance of Recess Blade Tips." ASME. J. Turbomach. January 2011; 133(1): 011023. https://doi.org/10.1115/1.4001134
Download citation file:
Get Email Alerts
Related Articles
Effects of Multiblocking and Axial Gap Distance on Performance of Partial Admission Turbines: A Numerical Analysis
J. Turbomach (July,2011)
Influence of Aerodynamic Loading on Rotor-Stator Aerodynamic Interaction in a Two-Stage Low Pressure Research Turbine
J. Turbomach (October,2007)
Unsteady Forces of Rotor Blades in Full and Partial Admission Turbines
J. Turbomach (October,2011)
Impact of Time-Resolved Entropy Measurement on a One-and-One-Half-Stage Axial Turbine Performance
J. Turbomach (March,2012)
Related Proceedings Papers
Related Chapters
Introduction
Turbine Aerodynamics: Axial-Flow and Radial-Flow Turbine Design and Analysis
Outlook
Closed-Cycle Gas Turbines: Operating Experience and Future Potential
Control and Operational Performance
Closed-Cycle Gas Turbines: Operating Experience and Future Potential