Effects of rotating inlet distortion on multistage compressor stability

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Journal of Turbomachinery

DOI:https://doi.org/10.1115/1.2836624· OSTI ID:250802

Longley, J P; Day, I J ^[1]; Shin, H W; Wisler, D C ^[2]; Plumley, R E; Silkowski, P D; Greitzer, E M; Tan, C S ^[3]

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1. Cambridge Univ. (United Kingdom). Whittle Lab.
2. GE Aircraft Engines, Cincinnati, OH (United States). Aerodynamics Research Lab.
3. Massachusetts Inst. of Technology, Cambridge, MA (United States). Gas Turbine Lab.

In multispool engines, rotating stall in an upstream compressor will impose a rotating distortion on the downstream compressor, thereby affecting its stability margin. In this paper experiments are described in which this effect was simulated by a rotating screen upstream of several multistage low-speed compressors. The measurements are complemented by, and compared with, a theoretical model of multistage compressor response to speed and direction of rotation of an inlet distortion. For corotating distortions, experiments show that the compressors exhibited significant loss in stability margin and that they could be divided into two groups according to their response. The first group exhibited a single peak in stall margin degradation when the distortion speed corresponded to roughly 50 percent of rotor speed. The second group showed two peaks in stall margin degradation corresponding to distortion speeds of approximately 25--35% and 70--75% of rotor speed. Detailed measurements suggest that the two types of behavior are linked to differences between the stall inception processes observed for the two groups of compressors and that a direct connection thus exists between the observed forced response and the unsteady flow phenomena at stall onset. For counterrotational distortions, all the compressors tested showed minimal loss of stability margin. The results imply that counterrotation of the fan and core compressor, or LP and HP compressors, could be a worthwhile design choice. Calculations based on the two-dimensional theoretical model show excellent agreement for the compressors, which had a single peak for stall margin degradation. Agreement is not good for compressors that had two peaks in the curve of stall margin shift versus distortion rotation speed. The discrepancy is attributed to the three-dimensional and short length scale nature of the stall inception process in these machines; this includes phenomena that have not yet been addressed in any model.

• Sponsoring Organization: USDOE
• OSTI ID: 250802
• Report Number(s): CONF-940626--
• Journal Information: Journal of Turbomachinery, Journal Name: Journal of Turbomachinery Journal Issue: 2 Vol. 118; ISSN JOTUEI; ISSN 0889-504X
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
FLOW RATE
GAS COMPRESSORS
GAS FLOW
GAS TURBINE ENGINES
STABILITY