Stall flutter prediction techniques for fan and compressor blades

El-Aini, Yehia M.; Capece, Vincent R.

doi:10.2514/6.1995-2652

Cited by 5 publications

(4 citation statements)

References 8 publications

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“…There have been few investigations that quantitatively evaluated fluid force and the blade vibration caused by turbulent flow or vortex shedding under near-stall conditions. Aerodynamic damping is an important factor in the evaluation of blade vibration responses, and there have been many studies on aerodynamic damping of a torsional mode [2,3,[5][6][7]. However, there have been few on aerodynamic damping of a bending mode.…”

Section: Introductionmentioning

confidence: 99%

“…While there have been many investigations of torsional stall flutter [1][2][3][4][5][6][7], which is self-excited vibration, there have been fewer investigations of separation bubbles [1,5,6,8] and turbulent flows [3], both of which are the causes of fluid excitation. There have been few investigations that quantitatively evaluated fluid force and the blade vibration caused by turbulent flow or vortex shedding under near-stall conditions.…”

Section: Introductionmentioning

confidence: 99%

“…Abdel-Rahim et al studied stall flutter numerically using a two-dimensional vortex method [1], They found that an entrainment of the stall propagation frequency and the blade natural frequency occurs when there is torsional vibra tion, resulting in pure torsional flutter, while their de-entrainment occurs when there is bending vibration, resulting in blade buffet ing. El-Aini and Capece developed a semi-empirical method for calculating torsional stall flutter that improved calculation accu racy [2]. It uses an empirical database combined with a linearized unsteady aerodynamic model of a flat plate.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Method for Predicting Unsteady Vibration of Gas Turbine Compressor Blades Under Subsonic Near-Stall Conditions

Yamaguchi

Takahashi

2014

Journal of Engineering for Gas Turbines and Power

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Wind tunnel tests and numerical calculations using computational fluid dynamics (CFD) analysis and structural finite element analysis were conducted to clarify the vibration characteristics of gas turbine compressor blades under subsonic near-stall conditions. The results show that discrete low-frequency components of pressure are created by vari ation o f the separation region and that discrete high-frequency components are created by vortex shedding when the compressor blade incidence angle is in the stall region. The natural frequency component resonated by the random fluid force is dominant in blade vibration. The numerically calculated phenomena agree well with the measured phenom ena. The vibration amplitude increases with the incidence angle and the Mach number, and it increases rapidly at higher angles. A simple method for predicting the vibration stress using static calculations is reasonably accurate.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Method for Predicting Unsteady Vibration of Gas Turbine Compressor Blades Under Subsonic Near-Stall Conditions

Yamaguchi

Takahashi

2014

Journal of Engineering for Gas Turbines and Power

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“…While considerable effort has been devoted to the development of unsteady aerodynamic models for flutter, accurate predictions of stall flutter have remained elusive. As a result, current stall flutter prediction systems rely on purely empirical correlations of flutter boundaries based on previous rig and engine testing, simplified separation models, or semi-empirical methods (EL-Aini and Capece, 1995).…”

Section: Introductionmentioning

confidence: 99%

Oscillating Cascade Aerodynamics at Large Mean Incidence

Buffum

Capece

King

et al. 1996

Volume 5: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation;

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The aerodynamics of a cascade of airfoils oscillating in torsion about the midchord is investigated experimentally at a large mean incidence angle and, for reference, at a low mean incidence angle. The airfoil section is representative of a modem, low aspect ratio, fan blade tip section. Time-dependent airfoil surface pressure measurements were made for reduced frequencies of up to i.2 for out-of-phase oscillations at a Mach number of 0.5 and chordal incidence angles of 0°and 10°; the Reynolds number was 0.gx10 6. For the 10°chordal incidence angle, a separation bubble formed at the leading edge of the suction surface. The separated flow field was found to have a dramatic effect on the chordwise distribution of the unsteady pressure.In this region, substantial deviations from the attached flow data were found with the deviations becoming less apparent in the aft region of the airfoil for all reduced frequencies. In particular, near the leading edge the separated flow had a strong destabilizing influence while the attached flow had a strong stabilizing influence.

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