High Speed Compressor Surge With Application to Active Control

Author(s):  
A. M. Cargill ◽  
C. Freeman

This paper discusses the mechanics of surge as observed on the high speed axial compressors of modern aero-engines. It argues that the initial stage of the instability consists of a high amplitude blast wave that develops non-linearly from a small scale disturbance and is thus not correctly described by traditional small perturbation stability theories. It follows from this that active control schemes of the global type may be inappropriate, since to be effective, control would have to be applied in a short time and in a very detailed manner, requiring a large number of transducers and actuators. Active control may, though, be effective in controlling the disturbances that grow into the above blast wave and in the control of other phenomena such as rotating stall, given an adequate number of transducers.

1991 ◽  
Vol 113 (2) ◽  
pp. 303-311 ◽  
Author(s):  
A. M. Cargill ◽  
C. Freeman

This paper discusses the mechanics of surge as observed on the high-speed axial compressors of modern aero-engines. It argues that the initial stage of the instability consists of a high-amplitude blast wave that develops nonlinearly from a small-scale disturbance and is thus not correctly described by traditional small perturbation stability theories. It follows from this that active control schemes of the global type may be inappropriate, since to be effective, control would have to be applied in a short time and in a very detailed manner, requiring a large number of transducers and actuators. Active control may, though, be effective in controlling the disturbances that grow into the above blast wave and in the control of other phenomena such as rotating stall, given an adequate number of transducers.


Author(s):  
Matthew R. Feulner ◽  
Gavin J. Hendricks ◽  
James D. Paduano

Using a two dimensional compressible flow representation of axial compressor dynamics, a control-theoretic input-output model is derived which is of general utility in rotating stall/surge active control studies. The derivation presented here begins with a review of the fluid dynamic model, which is a 2D stage stacking technique that accounts for blade row pressure rise, loss and deviation as well as blade row and inter-blade row compressible flow. This model is extended to include the effects of the upstream and downstream geometry and boundary conditions, and then manipulated into a transfer function form that dynamically relates actuator motion to sensor measurements. Key relationships in this input-output form are then approximated using rational polynomials. Further manipulation yields an approximate model which is in standard form for studying active control of rotating stall and surge. As an example of high current relevance, the transfer function from an array of jet actuators to an array of static pressure sensors is derived. Numerical examples are also presented, including a demonstration of the importance of proper choice of sensor and actuator locations, as well as a comparison between sensor types. Under a variety of conditions, it was found that sensor locations near the front of the compressor or in the downstream gap are consistently the best choices, based on a quadratic optimization criterion and a specific 3-stage compressor model. The modeling and evaluation procedures presented here are a first step toward a rigorous approach to the design of active control systems for high speed axial compressors.


Author(s):  
I. J. Day ◽  
T. Breuer ◽  
J. Escuret ◽  
M. Cherrett ◽  
A. Wilson

As part of a European collaborative project, four high speed compressors were tested to investigate the generic features of stall inception in aero-engine type compressors. Tests were run over the full speed range to identify the design and operating parameters which influence the stalling process. A study of data analysis techniques was also conducted in the hope of establishing early warning of stall. The work presented here is intended to relate the physical happenings in the compressor to the signals that would be received by an active stall control system. The measurements show a surprising range of stall related disturbances and suggest that spike-type stall inception is a feature of low speed operation while modal activity is clearest in the mid speed range. High frequency disturbances were detected at both ends of the speed range and non-rotating stall, a new phenomenon, was detected in three out of the four compressors. The variety of the stalling patterns, and the ineffectiveness of the stall warning procedures, suggests that the ultimate goal of a flightworthy active control system remains some way off.


Author(s):  
S. P. C. Belfroid ◽  
J. Golliard ◽  
O. Vijlbrief

Pipes with a corrugated inner surface, as used in flexible pipes for gas production and transport, can generate a high amplitude tonal sound (singing). Small quantities of liquid can result in a significant amplitude reduction or total mitigation of this sound production. To evaluate different potential mechanisms, liquid injection tests were done in both a horizontal and vertical small scale (49 mm) setup including high speed camera recordings using a transparent corrugated section. The singing amplitude decreased linearly with the liquid injection rate for both orientations, although the effect in the vertical setup was even faster. Liquid injection resulted also in higher onset velocities. The video recordings showed partially filled corrugations. For horizontal corrugations, liquid crept upward in the corrugations. In the vertical test, liquid accumulated at the upward edge with intermitted liquid spill over to downstream corrugations. The liquid fill up did not change significantly with higher liquid loads. Taking the fill-up grade and additional damping into account, a match could be made between the measured singing amplitude and a predicted singing amplitude as function of liquid rate. However, no model has been found to predict the liquid fill-up yet.


Author(s):  
Paul Xiubao Huang ◽  
JianAn Yin

Compressor surge is a complete breakdown in compression resulting in an abrupt momentary reversal of gas flow and the violent pressure fluctuation with relatively low frequency and high amplitude. It commonly exists in dynamic type turbo compressors, particularly axial compressor and jet engine, or turbo charger for reciprocating engines. It is generally accepted that surge is preceded by a rotating stall, a situation of a few stalled blades rotating around compressor annulus (cascade) with much higher frequency. In jet engine, violent surge event typically produces a frightening loud bang, lots of vibrations and could cause catastrophic structural failures if not timely managed. Naturally, as important matters as rotating stall and surge, there have been tremendous R/D efforts from academia, government and industry devoted to this area, especially since jet engines became the prime powerhouses for modern airplanes. Despite of all the efforts, there still seems to be a more urgent need to understand the physical characteristics of the transition from a rotating stall to surge that has mystified researchers due to its transient nature. Fundamental questions remain unanswered even today, such as: What exactly triggers the surge to take place from a rotating stall? What is the physical nature of a compressor system or a local incipient surge: is it a movement of wave or fluid particles or both? How to estimate the quantitative destructive forces of a severe surge, that is, the maximum possible surge strength? This paper attempts to answer these questions by applying the classical Shock Tube Theory to the transient process from rotating stall to surge. The Shock Tube analogy is established with the hypothesis (implied from experimental observations) that an instant zero through flow condition exists inside a stalled cascade cell or dynamic compressor that triggers surge. It is revealed that surge event consists of a pair of non-linear compression and expansion waves (CW & EW) that instantly reverse gas flow (IRFF) by the pushing force of upstream propagating CW and the pulling force from downstream travelling EW. The surge strength is shown to be proportional to the square root of the pressure ratio of the involved cascade or compressor. Surge Rules are deduced to predict the location of surge initiation, the minimum and maximum surge strengths, travelling directions and speed. Moreover, a pro-active control strategy called SEWI (Surge Early Warning Initiative) is proposed using the unique characteristics of CW-IRFF-EW formation of a cascade cell induced surge as precursors for subsequent warning and controls before the destructive compressor surge takes place.


Author(s):  
Dirk C. Leinhos ◽  
Stephen G. Scheidler ◽  
Leonhard Fottner ◽  
Frank Grauer ◽  
Jakob Hermann ◽  
...  

The aerodynamic stability of aero engine compressors must be assured by active control systems in all operating conditions when the design surge margin is reduced in order to improve efficiency. While this has been investigated only on compressor rigs and single-spool engines in the past, this study focuses on the active control of the LARZAC 04 twin-spool turbofan. The objective is to demonstrate potential benefits, problems and solutions and also to provide a data base for numerical modeling and simulation of the capabilities of active control. Three different control strategies have been employed each of which refers to a specific operating condition and instability inception of the engine: The attenuation of disturbances travelling at rotor speed by modulated air injection into the LPC in the high speed range, the recovery of fully developed LPC stall at low speeds with a minimized amount of air and finally a constant air recirculation (HPC exit to LPC inlet) for stabilizing the compression system at different speeds based on the monitoring of a stability parameter. The injector is mounted upstream of the LPC and has ten circumferentially distributed nozzles for air injection into the tip region of the first rotor. The injected air which is either taken from an external source or from bleed air ports at the HPC exit is controlled by high-bandwidth direct-drive-valves. Disturbances travelling at rotor speed can be detected and attenuated with modulated air injection leading to a delay of stall onset. Fully developed rotating stall in the LPC was eliminated by asymmetric injection based on modal control strategies with less air than needed with constant air injection. By using online-stability-monitoring it is possible to initiate constant air recirculation when approaching the surge line, though the current design of the injector does not allow for large extension of the operating range for all spool speeds.


Author(s):  
K. M. Eveker ◽  
D. L. Gysling ◽  
C. N. Nett ◽  
O. P. Sharma

Aeroengines operate in regimes for which both rotating stall and surge impose low flow operability limits. Thus, active control strategies designed to enhance operability of aeroengines must address both rotating stall and surge as well as their interaction. In this paper, a previously developed nonlinear control strategy that achieves simultaneous active control of rotating stall and surge is applied to a high-speed 3-stage axial flow compression system with operating parameters representative of modern aeroengines. The controller is experimentally validated for 2 compressor builds and its robustness to radial distortion assessed. For actuation, the control strategy utilizes an annulus-averaged bleed valve with bandwidth on the order of the rotor frequency. For sensing, measurements of the circumferential asymmetry and annulus-averaged unsteadiness of the flow through the compressor are used. Experimental validation of simultaneous control of rotating stall and surge in a high-speed environment with minimal sensing and actuation requirements is viewed as another important step towards applying active control to enhance operability of compression systems in modem aeroengines.


1996 ◽  
Vol 118 (1) ◽  
pp. 1-10 ◽  
Author(s):  
M. R. Feulner ◽  
G. J. Hendricks ◽  
J. D. Paduano

Using a two-dimensional compressible flow representation of axial compressor dynamics, a control-theoretic input–output model is derived, which is of general utility in rotating stall/surge active control studies. The derivation presented here begins with a review of the fluid dynamic model, which is a two-dimensional stage stacking technique that accounts for blade row pressure rise, loss, and deviation as well as blade row and interblade row compressible flow. This model is extended to include the effects of the upstream and downstream geometry and boundary conditions, and then manipulated into a transfer function form that dynamically relates actuator motion to sensor measurements. Key relationships in this input–output form are then approximated using rational polynomials. Further manipulation yields an approximate model in standard form for studying active control of rotating stall and surge. As an example of high current relevance, the transfer function from an array of jet actuators to an array of static pressure sensors is derived. Numerical examples are also presented, including a demonstration of the importance of proper choice of sensor and actuator locations, as well as a comparison between sensor types. Under a variety of conditions, it was found that sensor locations near the front of the compressor or in the downstream gap are consistently the best choices, based on a quadratic optimization criterion and a specific three-stage compressor model. The modeling and evaluation procedures presented here are a first step toward a rigorous approach to the design of active control systems for high-speed axial compressors.


1998 ◽  
Vol 120 (3) ◽  
pp. 440-445 ◽  
Author(s):  
K. M. Eveker ◽  
D. L. Gysling ◽  
C. N. Nett ◽  
O. P. Sharma

Aeroengines operate in regimes for which both rotating stall and surge impose low-flow operability limits. Thus, active control strategies designed to enhance operability of aeroengines must address both rotating stall and surge as well as their interaction. In this paper, a previously developed nonlinear control strategy that achieves simultaneous active control of rotating stall and surge is applied to a high-speed three-stage axial flow compression system with operating parameters representative of modern aeroengines. The controller is experimentally validated for two compressor builds and its robustness to radial distortion assessed. For actuation, the control strategy utilizes an annulus-averaged bleed valve with bandwidth on the order of the rotor frequency. For sensing, measurements of the circumferential asymmetry and annulus-averaged unsteadiness of the flow through the compressor are used. Experimental validation of simultaneous control of rotating stall and surge in a high-speed environment with minimal sensing and actuation requirements is viewed as another important step toward applying active control to enhance operability of compression systems in modern aeroengines.


2021 ◽  
Vol 11 (15) ◽  
pp. 6899
Author(s):  
Abdul Aabid ◽  
Sher Afghan Khan ◽  
Muneer Baig

In high-speed fluid dynamics, base pressure controls find many engineering applications, such as in the automobile and defense industries. Several studies have been reported on flow control with sudden expansion duct. Passive control was found to be more beneficial in the last four decades and is used in devices such as cavities, ribs, aerospikes, etc., but these need additional control mechanics and objects to control the flow. Therefore, in the last two decades, the active control method has been used via a microjet controller at the base region of the suddenly expanded duct of the convergent–divergent (CD) nozzle to control the flow, which was found to be a cost-efficient and energy-saving method. Hence, in this paper, a systemic literature review is conducted to investigate the research gap by reviewing the exhaustive work on the active control of high-speed aerodynamic flows from the nozzle as the major focus. Additionally, a basic idea about the nozzle and its configuration is discussed, and the passive control method for the control of flow, jet and noise are represented in order to investigate the existing contributions in supersonic speed applications. A critical review of the last two decades considering the challenges and limitations in this field is expressed. As a contribution, some major and minor gaps are introduced, and we plot the research trends in this field. As a result, this review can serve as guidance and an opportunity for scholars who want to use an active control approach via microjets for supersonic flow problems.


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