A new approach, steady micro air injection from the casing, is proposed to improve the stability of a three-stage low-speed axial compression system. Although the injection rate is designated to be only a few ten thousandth of the compressor flow rate, such an injection is able to trigger the unsteady response and thus lower the mass flow rate at stall for up to 5.83%. At the same time, it keeps the steady compressor characteristic with no injection unchanged. In order to verify that the compressor response is indeed unsteady, experiments at various injection configurations are performed, which include different injection angles, axial gaps between injector and blade leading edge, radial penetration of injector and the amount of injected air. Evidences of the unsteady response are further demonstrated through dynamic signal analysis using a wavelet-based method to show the behavior of early flow disturbances under the influence of injection. Numerical analyses performed at near stall condition show that the tip clearance vortices do response to the micro-injection, and thus delay the inception of stall.

Issue Section:
Technical Papers
Keywords:
gas turbines, compressors, flow instability, vortices, rotational flow
Topics:
Compressors, Ejectors, Flow (Dynamics), Blades
1.
Epstein
,
A. H.
,
Williams
,
J. E.
, and
Greitzer
,
E. M.
,
1989
, “
Active Suppression of Aerodynamic Instabilities in Turbomachinery
,”
J. Propul. Power
,
5
(
2
), pp.
204
–
211
.
2.
Greitzer
,
E. M.
, 1998, “Smart Jet Engines—Case History of a Multidisciplinary Research Program,” JSME Int. J. Series B,41, No. 1.
3.
Day
,
I. J.
,
1993
, “
Active Suppression of Rotating Stall and Surge in Axial Compressors
,”
ASME J. Turbomach.
,
115
, pp.
40
–
47
.
4.
Goto
,
A.
,
1994
, “
Suppression of Mixed-Flow Pump Instability and Surge by the Active Alteration of Impeller Secondary Flows
,”
ASME J. Turbomach.
,
116
, pp.
621
–
634
.
5.
Behnken, R. L., Leung, M., and Murray, R. M., 1997, “Characterizing the Effects of Air Injection on Compressor Performance for Use in Active Control of Rotating Stall,” ASME 97-GT-316.
6.
Weigl
,
H. J.
,
Paduano
,
J. D.
,
Frechette
,
L. G.
,
Epstein
,
A. H.
,
Greitzer
,
E. M.
,
Bright
,
M. M.
, and
Strazisar
,
A. J.
,
1998
, “
Active Stabilization of Rotating Stall and Surge in a Transonic Single Stage Axial Compressor
,”
ASME J. Turbomach.
,
120
, pp.
625
–
636
.
7.
Suder, K. L., Hathaway, M. D., Thorp, S. A., Strazisar, A. J., and Bright, M. B., 2000, “Compressor Stability Enhancement using Discrete Tip Injection,” ASME 2000-GT-650.
8.
Xu, G., Cheng, X., Nie, C., and Chen, J., 2001, “Unsteady Response to the Tip Injection in a Low-Speed Axial Compressor,” Proc., 5th ISAIF, Vol. 1, pp. 349–358, Gdansk, Poland.
9.
Lin, F., Chen, J., and Li, M., 2001, “Experimental Investigation on Unsteady Rotor Tip Flows in a High Speed Compressor Throttled to Stall,” ASME 2002-GT-30360.
10.
Hoying, D. A., Tan, C. S., Vo, H. D., and Greitzer, E. M., 1998, “Role of Blade Passage Flow Structures in Axial Compressor Rotating Stall Inception,” ASME 98-GT-588.
11.
Cheng, X., Chen, J., and Nie, C., 1999, “Investigation on the Precursor Behavior of Compressor Rotating Stall through Two-Dimensional Wavelet Transform,” Proc. ICET, pp. 278–284, Beijing, China.
Copyright © 2002
 by ASME
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