Journal of Turbomachinery

Volume: Page/CID:

A Review of Surface Roughness Effects in Gas Turbines
The effects of surface roughness on gas turbine performance are reviewed based on publications in the open literature over the past 60 years. Empirical roughness correlations routinely employed for dr...

Aerothermal Impact of Stator-Rim Purge Flow and Rotor-Platform Film Cooling on a Transonic Turbine Stage
The sealing of the stator-rotor gap and rotor-platform cooling are vital to the safe operation of the high-pressure turbine. Contrary to the experience in subsonic turbines, this paper demonstrates th...

J. Turbomach. / Volume 132 / Issue 2 / Research Papers

Predictions of Turbulent Flow for the Impeller of a NASA Low-Speed Centrifugal Compressor

J. Turbomach. -- April 2010 -- Volume 132, Issue 2, 021005 (8 pages)
doi:10.1115/1.3140824

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ABSTRACT

REFERENCES (16)

Author(s):
K. M. Guleren
Department of Mechanical Engineering, Faculty of Engineering, Cumhuriyet University, Sivas, 58140, Turkey

I. Afgan
Institute of Avionics and Aeronautical Engineering, Air University, Sector E-9, Islamabad, 44200, Pakistan

A. Turan
School of MACE, University of Manchester, George Begg Building, Sackville Street, P.O. Box 88, Manchester, M60 1QD, UK

Theturbulent flow inside a low-speed centrifugal compressor at design conditionis investigated using large-eddy simulation (LES) comprising of up to26×10⁶ computational volume cells. Unlike in the past, the currentstudy's special emphasis is placed on the turbulence field evolutioninside the impeller. LES predictions suggest that the Boussinesq hypothesisdoes not seem to be valid, especially near the exitof the impeller where the blade unloading takes place. Reynoldsstress variations show a tendency toward an “axisymmetric expansion” typeof turbulence after the impeller exit for which the subgrid-scalestress contribution shows a monotonic decrease. Probability density function analysisfor the leakage flow show that instantaneous velocities in thewake region are less intermittent as compared with those inthe jet. Time spectra analysis display also another feature thatthe energy cascade proceeds at a higher rate and lastslonger in the wake region than in the tip jetregion.