The effect of adding roughness and thickness to a transonic axial compressor rotor
- National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center
- Flow Application Research and Sermatech International Inc., Fremont, CA (United States)
The performance deterioration of a high-speed axial compressor rotor due to surface roughness and airfoil thickness variations is reported. A 0.025 mm (0.001 in.) thick rough coating with a surface finish of 2.54--3.18 rms {micro}m (100--125 rms {micro}in.) is applied to the pressure and suction surface of the rotor blades. Coating both surfaces increases the leading edge thickness by 10% at the hub and 20% at the tip. Application of this coating results in a loss in efficiency of 6 points and a 9% reduction in the pressure ratio across the rotor at an operating condition near the design point. To separate the effects of thickness and roughness, a smooth coating of equal thickness is also applied to the blade. The smooth coating surface finish is 0.254--0.508 rms {micro} (10--20 rms {micro}in.), compared to the bare metal blade surface finish of 0.508 rms {micro}m (20 rms {micro}in.). The smooth coating results in approximately half of the performance deterioration found from the rough coating. Both coatings are then applied to different portions of the blade surface to determine which portions of the airfoil are most sensitive to thickness/roughness variations. Aerodynamic performance measurements are presented for a number of coating configurations at 60, 80, and 100% of design speed. The results indicate that thickness/roughness over the first 2% of blade chord accounts for virtually all of the observed performance degradation for the smooth coating, compared to about 70% of the observed performance degradation for the rough coating. The performance deterioration is investigated in more detail at design speed using laser anemometer measurements as well as predictions generated by a quasi-three-dimensional Navier-Stokes flow solver, which includes a surface roughness model. Measurements and analysis are performed on the baseline blade and the full-coverage smooth and rough coatings.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 136529
- Report Number(s):
- CONF-940626-; ISSN 0889-504X; TRN: IM9552%%71
- Journal Information:
- Journal of Turbomachinery, Vol. 117, Issue 4; Conference: 39. international gas turbine and aeroengine congress and exposition, The Hague (Netherlands), 13-16 Jun 1994; Other Information: PBD: Oct 1995
- Country of Publication:
- United States
- Language:
- English
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