Spike type of stall inception in the tandem rotor

Abstract

There are two known mechanisms of inception of rotating stall in the compressor, modal wave inception and spike inception. However, the stall inception mechanisms for a tandem-rotor have not been explored so far in detail. The paper explores the unsteady behaviour of the tandem rotor. Unsteady casing pressure measurements are carried out with the help of seven equispaced unsteady pressure sensors. The casing pressure traces are analysed using wavelet transforms, fast Fourier transform, discrete spatial Fourier series, travelling wave energy method and correlation techniques to identify the nature of the stall cells. The changes observed in the stall cells during the transition from the stable mode of operation to the fully stalled mode and back from the stall regime to the stable operating condition are investigated in detail. It is observed that the stall incepts in the form of a low-intensity spike, which later evolves as a long-length scale disturbance in the fully developed stall region. The initial stall disturbance is found to be rotating with 75% of the rotor speed. The speed of the stall cells is reduced to 61% of the rotor speed in a fully developed region. The number and size of stall cells increase as the mass flow is throttled. The number and size of the stall cells are strongly coupled with the leading-edge incidence pattern. During the transition from the stall regime to the stable operating condition, the mass flow of the compressor increases, which reduces the flow incidence angle of the tandem rotor. Thus, the separation region shrinks during this transition leading to a reduction in the size of the stall cells. The stall in the tandem-rotor is primarily associated with the tip leakage flow. The rotating disturbances in the tandem-rotor originate due to the leading-edge flow separation of the forward rotor blade. Leading-edge separation of the aft rotor, which arises due to interaction of the forward rotor tip leakage vortex, is effectively suppressed with the help of the gap-nozzle flow. For a comprehensive unsteady analysis, the different techniques need to be used in combination.

Keywords

compressor aerodynamics tandem rotor blade stall inception unsteady flow spike modal stall

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References

Guochuan

Biaonan

Bingheng

. Experimental investigation of tandem blade cascades with double-circular arc profiles. In: ASME 1985 Beijing international gas turbine symposium and exposition. New York, NY: American Society of Mechanical Engineers; 1985, pp. V001T02A036–V001T02A036.

Brent

. Single-stage experimental evaluation of tandem-airfoil rotor and stator blading for compressors. Part 2: Data and performance for stage A. Washington, D.C: NASA CR-120804; 1972.

Bammert

Beelte

. Investigations of an axial flow compressor with tandem cascades. Journal of Engineering for Power 1980; 102(4): 971–977.

Roy

Saha

. Experimental analysis of controlled diffusion compressor cascades with single and tandem airfoils. New York, NY: The American Society of Mechanical Engineers, 1995, Vol 7, p. 1995.

Falla

GAC

. Numerical investigation of the flow in tandem compressor cascades. Master’s thesis. Vienna, Austria: Institute of Thermal Power Plants, Vienna University of Technology, 2004.

McGlumphy

Wellborn

, et al. Numerical investigation of tandem airfoils for subsonic axial-flow compressor blades. J Turbomach 2009; 131(2): 021018.

Kumar

Pradeep

. Design methodology of a highly loaded tandem rotor and its performance analysis under clean and distorted inflows. Proc IME C J Mech Eng Sci 2021; 235: 6798–6821. DOI: 10.1177/09544062211016021.

Kumar

Pradeep

. Performance evaluation of a tandem rotor under design and off-design operation. In: Turbo Expo: Power For Land, Sea, and Air, Oslo, Norway. June 11–15, 2018, Vol. 50992. New York, NY: American Society of Mechanical Engineers, p. V02AT39A009.

Mohsen

Owis

Hashim

. The impact of tandem rotor blades on the performance of transonic axial compressors. Aero Sci Technol 2017; 67: 237–248.

10.

Schneider

Kožulović

. Flow characteristics of axial compressor tandem cascades at large off-design incidence angles. In: Turbo Expo: Power For Land, Sea, and Air, San Antonio, Texas, USA. June 3–7, 2013, Vol. 55225. New York, NY: American Society of Mechanical Engineers, p. V06AT35A011.

11.

Heinrich

Tiedemann

Peitsch

. Experimental investigations of the aerodynamics of highly loaded tandem vanes in a high-speed stator cascade. In: Turbo Expo: Power For Land, Sea, and Air, Charlotte, North Carolina, USA. June 26–30, 2017, Vol. 50787. New York, NY: American Society of Mechanical Engineers, p. V02AT39A005.

12.

Mao

Liu

Zhang

. Hub clearance effects of a cantilevered tandem stator on the performance and flow behaviors in a small-scale axial flow compressor. Aero Sci Technol 2019; 91: 219–230.

13.

Han

, et al. Improving the operating range using a centrifugal compressor with a tandem impeller. Aero Sci Technol 2020; 96: 105548.

14.

Konrath

Peitsch

Heinrich

. An analysis of the secondary flow around a tandem blade under the presence of a tip gap in a high-speed linear compressor cascade. In: Turbo Expo: Power For Land, Sea, and Air, Virtual, Online. September 21 -25, 2020. Vol. 84065. New York, NY: American Society of Mechanical Engineers, p. V02AT32A001.

15.

Day

I. J

. (January 1, 1993). “Stall Inception in Axial Flow Compressors.”

ASME.

J. Turbomach. January 1993; 115(1): 1–9.

16.

McDougall

Cumpsty

Hynes

. Stall inception in axial compressors. J Turbomach 1990; 112(1): 116–123.

17.

Inoue

Kuroumaru

Tanino

, et al. Propagation of multiple short-length-scale stall cells in an axial compressor rotor. J Turbomach 2000; 122(1): 45–54.

18.

Inoue

Kuroumaru

Yoshida

, et al. Short and long length-scale disturbances leading to rotating stall in an axial compressor stage with different stator/rotor gaps. J Turbomach 2002; 124(3): 376–384.

19.

Deppe

Saathoff

Stark

. Spike-type stall inception in axial-flow compressors. In: Proceeding of 6th Conference on Turbomachinery, Fluid Dynamics and Thermodynamics, Lille, France, March 7–11 2005.

20.

Lin

Chen

. Long-to-short length-scale transition: a stall inception phenomenon in an axial compressor with inlet distortion. J Turbomach 2006; 128(1): 130–140.

21.

Cameron

Bennington

Ross

, et al. Effects of steady tip clearance asymmetry and rotor whirl on stall inception in an axial compressor. Turbo Expo: Power for Land, Sea, and Air 2007; 47950: 457–468.

22.

Tan

Greitzer

. Criteria for spike initiated rotating stall. J Turbomach 2008; 130(1): 011023.

23.

Dejene Toge

Pradeep

. Experimental investigation of stall inception and its propagation in a contra rotating axial fan under radial inflow distortion. In: Turbo Expo: Power for Land, Sea, and Air, Charlotte, North Carolina, USA. June 26–30, 2017, Vol. 50817. New York, NY: American Society of Mechanical Engineers, p. V02DT46A006.

24.

Torrence

Compo

. A practical guide to wavelet analysis. Bull Am Meteorol Soc 1998; 79(1): 61–78.

25.

Cameron

Morris

. Analysis of axial compressor stall inception using unsteady casing pressure measurements. J Turbomach 2013; 135(2).

26.

Tryfonidis

Etchevers

Paduano

, et al. Pre-stall behavior of several high-speed compressors. J Turbomach 1995; 117(1): 62–80.

27.

Park

. Unsteady disturbance structures in axial flow compressor stall inception. Cambridge, MA: Massachusetts Institute of Technology, 1994.