Experimental Study of Surge Precursors in a High-Speed Multistage Compressor

2012 ◽  
Author(s):  
Nicolas Courtiade ◽  
Xavier Ottavy
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Rotation Speed ◽  
Critical Size ◽  
Rotating Stall ◽  
Characteristic Line ◽  
High Frequency Response ◽  
Stable Operating ◽  
Multistage Compressor ◽  
Operating Points

Pressure measurements using high frequency response sensors have been carried out on the 3rd rotor of the 3 1/2-stage high speed compressor CREATE (rotation speed: 11543 RPM, Rotor 1 tip speed: 313 m/s), over the complete characteristic line and during the surge transient. It seems that precursors to the instabilities occurring near surge are observable at stable operating points. Just before the surge, these precursors characterized as rotating disturbances transition smoothly to part span rotating stall cells, and bring the machine to surge as they grow and reach a critical size: this paper presents a detailed analysis of the phenomena of rotating stall and surge transient and shows that it is possible to develop an anti-surge active control system based on the early detection of the precursors.

Experimental Study of Surge Precursors in a High-Speed Multistage Compressor

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Nicolas Courtiade ◽  
Xavier Ottavy
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Rotation Speed ◽  
Characteristic Line ◽  
Pressure Measurements ◽  
High Frequency Response ◽  
Stable Operating ◽  
Variable Duration ◽  
Multistage Compressor ◽  
Operating Points

Pressure measurements using high frequency response sensors have been carried out on the third rotor of the 3.5-stage high speed compressor CREATE (rotation speed: 11,543 RPM, Rotor 1 tip speed: 313 m/s) over the complete characteristic line and during the surge transient. Precursors to the instabilities occurring near surge are observable at stable operating points. Just before surge, these precursors characterized as rotating disturbances grow in amplitude and provoke the onset a stall cell after a variable duration, which finally triggers surge. This paper presents a detailed analysis of the phenomena of rotating instabilities and surge transient and shows that it is possible to develop an antisurge active control system based on the early detection of the precursors.

Fan Stability With Leading Edge Damage: Blind Prediction and Validation

2021 ◽  
Author(s):  
E. J. Gunn ◽  
T. Brandvik ◽  
M. J. Wilson ◽  
R. Maxwell
Keyword(s):  
Supersonic Flow ◽  
High Speed ◽  
Leading Edge ◽  
Rotating Stall ◽  
Stall Inception ◽  
Blind Prediction ◽  
Edge Damage ◽  
The Impact ◽  
Operating Points ◽  
Relative Flow

Abstract This paper considers the impact of a damaged leading edge on the stall margin and stall inception mechanisms of a transonic, low pressure ratio fan. The damage takes the form of a squared-off leading edge over the upper half of the blade. Full-annulus, unsteady CFD simulations are used to explain the stall inception mechanisms for the fan at low- and high-speed operating points. A combination of steady and unsteady simulations show that the fan is predicted to be sensitive to leading edge damage at low speed, but insensitive at high speed. This blind prediction aligns well with rig test data. The difference in response is shown to be caused by the change between subsonic and supersonic flow regimes at the leading edge. Where the inlet relative flow is subsonic, rotating stall is initiated by growth and propagation of a subsonic leading edge flow separation. This separation is shown to be triggered at higher mass flow rates when the leading edge is damaged, reducing the stable flow range. Where the inlet relative flow is supersonic, the flow undergoes a supersonic expansion around the leading edge, creating a supersonic flow patch terminated by a shock on the suction surface. Rotating stall is triggered by growth of this separation, which is insensitive to leading edge shape. This creates a marked difference in sensitivity to damage at low- and high-speed operating points.

scholarly journals An Investigation of Surge in a High-Speed Centrifugal Compressor Using Digital PIV

2000 ◽  
Vol 123 (2) ◽  
pp. 418-428 ◽  
Author(s):  
Mark P. Wernet ◽  
Michelle M. Bright ◽  
Gary J. Skoch
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
High Speed ◽  
Transient Flow ◽  
Dynamic Pressure ◽  
Rotating Stall ◽  
Transient Pressure ◽  
Pressure Transducers ◽  
Stable Operating ◽  
Particle Imaging

Compressor stall is a catastrophic breakdown of the flow in a compressor, which can lead to a loss of engine power, large pressure transients in the inlet/nacelle, and engine flameout. The implementation of active or passive strategies for controlling rotating stall and surge can significantly extend the stable operating range of a compressor without substantially sacrificing performance. It is crucial to identify the dynamic changes occurring in the flow field prior to rotating stall and surge in order to control these events successfully. Generally, pressure transducer measurements are made to capture the transient response of a compressor prior to rotating stall. In this investigation, Digital Particle Imaging Velocimetry (DPIV) is used in conjunction with dynamic pressure transducers to capture transient velocity and pressure measurements simultaneously in the nonstationary flow field during compressor surge. DPIV is an instantaneous, planar measurement technique that is ideally suited for studying transient flow phenomena in high-speed turbomachinery and has been used previously to map the stable operating point flow field in the diffuser of a high-speed centrifugal compressor. Through the acquisition of both DPIV images and transient pressure data, the time evolution of the unsteady flow during surge is revealed.

Unsteady Viscous Flow in a High-Speed Core Compressor

1992 ◽  
Vol 114 (2) ◽  
pp. 287-294 ◽  
Author(s):  
M. A. Cherrett ◽  
J. D. Bryce
Keyword(s):  
High Speed ◽  
Secondary Flows ◽  
Pressure Measurements ◽  
High Frequency Response ◽  
Unsteady Viscous Flow ◽  
Novel Method ◽  
Multistage Compressor ◽  
Response Pressure ◽  
Random Fluctuations ◽  
Unsteady Pressure Measurements

A probe incorporating a miniature high-frequency response pressure transducer has been traversed behind the first three stages of a high-speed multistage compressor operating at throttle settings corresponding to near choke, peak efficiency, and near surge. A novel method of compensating for transducer temperature sensitivity was employed. Consequently, time-averaged pressures derived from the transducer were found to be in good agreement with pneumatic pressure measurements. Analysis of the unsteady pressure measurements revealed both the periodic and random fluctuations in the flow field. This provided information on rotor-rotor interaction effects and the nature of viscous blade wake and secondary flows in each stage.

Spatial Correlation Based Stall Inception Analysis

2007 ◽  
Author(s):  
Joshua D. Cameron ◽  
Scott C. Morris
Keyword(s):  
Spatial Correlation ◽  
High Speed ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Fourier Decomposition ◽  
Stall Inception ◽  
Pressure Transducers ◽  
High Frequency Response ◽  
Wide Range ◽  
Response Pressure

Investigations of stall inception and compressor pre-stall behavior have used a variety of techniques to make inferences about the mechanisms of rotating stall inception. Many of these techniques utilized data from arrays of circumferentially spaced hot-wires or high frequency response pressure transducers. This paper presents results from the application of several typical analysis techniques to the interpretation of unsteady casing pressure measurements recorded during two representative stall event in a high-speed axial compressor stage. Results from visual pressure trace inspection, spatial Fourier decomposition, wavelet filtering, and traveling wave energy techniques are presented and compared. The effects of measurement and analysis parameters are also briefly discussed. A new analysis technique based on windowed two-point spatial correlation between adjacent stall inception sensors is described. The method was found to provide both spatial and temporal information about rotating features in the compressor flow and is insensitive to low pass filtering and parameter selection over a wide range of values. It was also found to be valuable for analysis of both pre-stall and stall inception behavior.

An evaluation technique for high-frequency dynamic behavior of a sandwich microcantilever beam

2017 ◽  
Vol 21 (3) ◽  
pp. 1133-1149
Author(s):  
Yun Young Kim
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Beam Theory ◽  
Tone Burst ◽  
Ultrasonic Frequency ◽  
Vibration Modes ◽  
High Frequency Response ◽  
Frequency Regime ◽  
Contact Transducer ◽  
Microcantilever Beam

A method was developed to measure the first- and second-order vibration modes in a sandwich microcantilever beam oscillating in the megahertz frequency regime in the present study. Taking advantage of the ultrasonic frequency, a test platform was developed to induce free vibration of the microcantilever using a high-power radio frequency pulser that transmits tone burst signals to a contact transducer, and the resonant frequencies of the microcantilever were measured using a laser-optic interferometer. Results show that the microcantilever’s vibration above 8 MHz can be successfully detected, and its vibration modes were identified through a theoretical study based on the Euler–Bernoulli beam theory and a numerical analysis using the finite element method. The present study proposes a facile and effective way to actuate a high-speed sandwich microcantilever and detect its high-frequency response so that the technique can be employed to study the characteristics of micro- and nanomechanical sandwich structures and their properties.

scholarly journals Observations on Rotating Instabilities and Spike Type Stall Inception in a High-Speed Multistage Compressor

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Johannes Schreiber ◽  
Benoit Paoletti ◽  
Xavier Ottavy
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Stall Inception ◽  
Time Period ◽  
Type Flow ◽  
Different Types ◽  
Multistage Compressors ◽  
Multistage Compressor ◽  
Field Modulation ◽  
Rotating Instability

This work investigates high-frequency measurements for the contribution to the understanding of different stall inception types in high-speed multistage compressors. A 3.5-stage high-speed axial multistage compressor is investigated with a 2 MW test rig in the Laboratoire de Mécanique des Fluides et d’Acoustique (LMFA) at Ecole Centrale de Lyon, France. Two different types of instabilities arise in this compressor as a function of shaft speed. At part speed, a controversy called “rotating instability” type flow field modulation is identified with the measurements. New results are the demonstration of the periodic behavior of this instability and the analogy to classical frequency modulation, periodic to one revolution of the instability. Furthermore, the amplitude of the instability is modulated by the time period of a rotor revolution. At nominal speed, the abrupt spike type stall inception is detected, taking usually less than five rotor revolutions.

scholarly journals Unsteady Viscous Flow in a High Speed Core Compressor

1991 ◽  
Author(s):  
M. A. Cherrett ◽  
J. D. Bryce
Keyword(s):  
High Speed ◽  
Secondary Flows ◽  
Pressure Measurements ◽  
High Frequency Response ◽  
Unsteady Viscous Flow ◽  
Novel Method ◽  
Multistage Compressor ◽  
Response Pressure ◽  
Random Fluctuations ◽  
Unsteady Pressure Measurements

A probe incorporating a miniature high-frequency response pressure transducer has been traversed behind the first three stages of a high-speed multistage compressor operating at throttle settings corresponding to near choke, peak efficiency and near surge. A novel method of compensating for transducer temperature sensitivity was employed. Consequently, time-averaged pressures derived from the transducer were found to be in good agreement with pneumatic pressure measurements. Analysis of the unsteady pressure measurements revealed both the periodic and random fluctuations in the flowfield. This provided information on rotor-rotor interaction effects and the nature of viscous blade wake and secondary flows in each stage.

scholarly journals The impulsive motion of a liquid resulting from a particle collision

1998 ◽  
Vol 375 ◽  
pp. 345-361 ◽  
Author(s):  
R. ZENIT ◽  
M. L. HUNT
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Pressure Pulse ◽  
Fluid Pressure ◽  
Particle Diameter ◽  
Digital Camera ◽  
Particle Collision ◽  
High Frequency Response ◽  
Response Pressure ◽  
Impulse Pressure

When two particles collide in a liquid, the impulsive acceleration due to the rebound produces a pressure pulse that is transmitted through the fluid. Detailed measurements were made of the pressure pulse and the motion of the particles by generating controlled collisions with an immersed dual pendulum. The experiments were performed for a range of impact velocities, angles of incidence, and distances between the wall and the pairs of particles. The radiated fluid pressure was measured using a high-frequency-response pressure transducer, and the motion of the particles was recorded using a high-speed digital camera. The magnitude of the impulse pressure was found to scale with the particle velocity, the particle diameter and the density of the fluid. Additionally, a model is proposed to predict the impulse field in the fluid based on the impulse pressure theory. The model agrees well with the experimental measurements.

Influence of Rotor Tip Flow Field Mis-Prediction on Rotating Disturbance Near Surge in a High Speed Multistage Compressor

2016 ◽  
Author(s):  
Johannes Schreiber ◽  
Xavier Ottavy ◽  
Ghislaine Ngo Boum ◽  
Nicolas Gourdain
Keyword(s):  
Flow Field ◽  
High Frequency ◽  
High Speed ◽  
Periodic Oscillation ◽  
Aircraft Engine ◽  
Numerical Results ◽  
Operating Point ◽  
Stall Inception ◽  
Frequency Measurements ◽  
Multistage Compressor

In this work, unsteady numerical results and high-frequency measurements are investigated from nominal to loaded operating points with the objective to contribute to the understanding of pre-stall rotating disturbances. A 3.5 stages high speed axial multistage compressor is investigated on a 2 MW test rig in the laboratory of fluid mechanics (LMFA) at Ecole Centrale de Lyon, France. The compressor has been built by Snecma, and is representative of modern high-pressure rear blocks of a modern aircraft engine. The unsteady numerical results predict a rotating disturbance in the tip flow field of the rotor 2 at the loaded operating point. It causes a frequency which is not a multiple of the periodicity of the compressor, and is rotating at about 72% of the shaft speed. The mesh independency of this disturbance is ensured. The analysis of the circumferential and axial propagation of the disturbance reveals a rotating instability like phenomenon. Most characteristic is the very important periodic oscillation of the tip leakage vortex trajectory, leading to a modulation of the leakage flow in the neighboring tip gap. The influence of the neighboring blade rows is investigated by filtering their unsteady contribution by means of mixing planes up and/or downstream of the rotor 2. In either case, the rotating disturbance is found to be still present. There are no traces of this rotating disturbance in the high-frequency measurements investigated at a near surge operating point. A spike like stall inception and almost instantaneous surge inception is identified. The mis-prediction of the tip region flow field in the rotors 2 and 3 is believed to cause the mis-prediction of the pre-stall disturbance.

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