This paper describes the impact of axial slots on the flow field in a transonic rotor blade row. The presented results are completely based on time-accurate three-dimensional numerical simulations of a high pressure compressor front stage with and without casing treatment. Two different axial positions of a casing treatment consisting of axial slots were tested for their impact on flow stability and efficiency. The first tested position (configuration 1) was chosen in a conventional way. The slots extend approximately from the leading up to the trailing edge of the rotor blades. As expected, the simulations of the compressor stage with this configuration showed a significant increase in flow stability near surge compared to the solid wall case. However, a non-negligible decrease in efficiency is also observed. Analyses of flow interactions between casing treatment and rotor blade rows under transonic conditions lead to the general conclusion that the stabilizing effect of circumferential grooves or axial slots mainly results from their impact on the tip leakage flow and its resulting vortex. A characteristic vortex inside the slots is observed in the simulations with the conventionally positioned casing treatment. This vortex removes fluid out of downstream parts of the blade passage and feeds it back into the main flow further upstream. The resulting impact on the tip leakage flow is responsible for the increased flow stability. However, the interaction between the configuration 1 casing treatment flow and the blade passage flow results in a significant relocation of the blade passage shock in the downstream direction. This fact is a main explanation for the observed decrease in compressor efficiency. A second slot position (configuration 2) was tested with the objective to improve compressor efficiency. The casing treatment was shifted upstream, so that only 25% of the blade chord remained under the slots. The simulations carried out demonstrate that this shift positively affects the resulting efficiency, but maintains the increased level of flow stability. A time-accurate analysis of the flow shows clearly that the modified casing treatment stabilizes the tip leakage vortex and reduces the influence on the flow inside the blade passage.
Skip Nav Destination
Article navigation
July 2004
Technical Papers
A Numerical Investigation of the Flow Mechanisms in a High Pressure Compressor Front Stage With Axial Slots
Ingo Wilke,
Ingo Wilke
Technical University of Munich, Ballzmannstr. 15, Garching 85747, Germany
Search for other works by this author on:
Hans-Peter Kau
Hans-Peter Kau
Technical University of Munich, Ballzmannstr. 15, Garching 85747, Germany
Search for other works by this author on:
Ingo Wilke
Technical University of Munich, Ballzmannstr. 15, Garching 85747, Germany
Hans-Peter Kau
Technical University of Munich, Ballzmannstr. 15, Garching 85747, Germany
Contributed by the International Gas Turbine Institute and presented at the International Gas Turbine and Aeroengine Congress and Exhibition, Atlanta, GA, June 16–19, 2003. Manuscript received by the IGTI Dec. 2002; final revision Mar. 2003. Paper No. 2003-GT-38481. Review Chair: H. R. Simmons.
J. Turbomach. Jul 2004, 126(3): 339-349 (11 pages)
Published Online: September 3, 2004
Article history
Received:
December 1, 2002
Revised:
March 1, 2003
Online:
September 3, 2004
Citation
Wilke , I., and Kau , H. (September 3, 2004). "A Numerical Investigation of the Flow Mechanisms in a High Pressure Compressor Front Stage With Axial Slots ." ASME. J. Turbomach. July 2004; 126(3): 339–349. https://doi.org/10.1115/1.1731465
Download citation file:
Get Email Alerts
Related Articles
Experimental Investigation of Unsteady Flow Field in the Tip Region of an Axial Compressor Rotor Passage at Near Stall Condition With Stereoscopic Particle Image Velocimetry
J. Turbomach (July,2004)
Prestall Behavior of a Transonic Axial Compressor Stage via Time-Accurate Numerical Simulation
J. Turbomach (October,2008)
An Investigation of Wake-Shock Interactions in a Transonic Compressor With Digital Particle Image Velocimetry and Time-Accurate Computational Fluid Dynamics
J. Turbomach (October,2006)
Influence of Flow Coefficient, Stagger Angle, and Tip Clearance on Tip Vortex in Axial Compressors
J. Fluids Eng (November,2006)
Related Proceedings Papers
Related Chapters
Aerodynamic Performance Analysis
Axial-Flow Compressors
Outlook
Closed-Cycle Gas Turbines: Operating Experience and Future Potential
Large Eddy Simulations of a Confined Tip-Leakage Cavitating Flow with Special Emphasis on Vortex Dynamics
Proceedings of the 10th International Symposium on Cavitation (CAV2018)