Integrated Control of Rotating Stall and Surge in High-Speed Multi-Stage Compression Systems

1997 ◽  
Author(s):  
K. M. Eveker ◽  
D. L. Gysling ◽  
C. N. Nett ◽  
O. P. Sharma
Keyword(s):  
Active Control ◽  
Control Strategy ◽  
High Speed ◽  
Control Strategies ◽  
Integrated Control ◽  
Axial Flow ◽  
Rotating Stall ◽  
Low Flow ◽  
Multi Stage ◽  
Simultaneous Control

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.

Integrated Control of Rotating Stall and Surge in High-Speed Multistage Compression Systems

1998 ◽  
Vol 120 (3) ◽  
pp. 440-445 ◽  
Author(s):  
K. M. Eveker ◽  
D. L. Gysling ◽  
C. N. Nett ◽  
O. P. Sharma
Keyword(s):  
Active Control ◽  
Control Strategy ◽  
High Speed ◽  
Control Strategies ◽  
Integrated Control ◽  
Axial Flow ◽  
Rotating Stall ◽  
Low Flow ◽  
Simultaneous Control ◽  
Flow Compression

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.

Experiments in Active Stall Control of a Twin-Spool Turbofan Engine

2002 ◽  
Author(s):  
Dirk C. Leinhos ◽  
Stephen G. Scheidler ◽  
Leonhard Fottner ◽  
Frank Grauer ◽  
Jakob Hermann ◽  
...  
Keyword(s):  
Active Control ◽  
High Speed ◽  
Control Strategies ◽  
External Source ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Air Injection ◽  
Rotor Speed ◽  
Direct Drive ◽  
Specific Operating Condition

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.

A Method for Evaluating the Effect of Circumferential Inlet Distortion on the Aerodynamic Stability of Multi-Stage Axial-Flow Compressors

2010 ◽  
Author(s):  
Tsuguji Nakano ◽  
Andy Breeze-Stringfellow
Keyword(s):  
Steady State ◽  
High Speed ◽  
Axial Flow ◽  
Pressure Rise ◽  
Stability Limit ◽  
Rotating Stall ◽  
Classical Dynamic ◽  
Inlet Flow ◽  
Inlet Distortion ◽  
Multi Stage

A simple engineering parameter to evaluate the stability of high-speed multi-stage compressors with distorted inlet flow has been derived based on a simplified semi-compressible linear stability model. The parameter consists of steady-state flow quantities and geometric parameters of the compressor and it indicates that the circumferential integral of the slope of the steady-state individual blade row static pressure rise characteristics is important in the determination of the compressor stability limit in the presence of distortion. The parameter reduces to the author’s rotating stall inception parameter in the limit of non-distorted inlet flow. Since the model includes a downstream plenum and throttle, a condition for pure surge inception with undistorted inlet flow has been deduced. The pure surge conditions can be reduced to the classical dynamic and static instability conditions in the limit of a constant annulus area incompressible compressor. The results indicate that rotating stall always precedes surge instability, as many engineers and researchers would expect from experience. The parameter for instability with inlet distortion was calculated using test data measured in a high-speed 5-stage compressor with two different types of circumferential inlet distortion, and the results show that the parameter has a strong correlation with the data and is an improvement over the classical incompressible stability parameter. The results demonstrate that the parameter captures much of the physics important during the instability inception in a high-speed multi-stage compressor subjected to circumferential inlet distortion. The parameter clearly shows how each compressor component’s characteristics contribute to the overall stability in a high speed axial multi-stage compressor, therefore, it will aid engineers and designers in their understanding and prediction of the aerodynamic instability inception phenomena.

Analysis of Instability Inception in High-Speed Multi-Stage Axial-Flow Compressors

1996 ◽  
Author(s):  
Gavin J. Hendricks ◽  
Jayant S. Sabnis ◽  
Matthew R. Feulner
Keyword(s):  
High Speed ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Rotating Stall ◽  
Two Dimensional ◽  
One Dimensional ◽  
High Pressure Ratio ◽  
Multi Stage ◽  
Dimensional Domain ◽  
Axial Flow Compressors

A nonlinear, two-dimensional, compressible dynamic model has been developed to study rotating stall/surge inception and development in high speed, multi-stage, axial flow compressors. The flow dynamics are represented by the unsteady Euler equations, solved in each interblade row gap and inlet and exit ducts as two-dimensional domains, and in each blade passage as a one-dimensional domain. The resulting equations are solved on a computational grid. The boundary conditions between domains are represented by ideal turning coupled with empirical loss and deviation correlations. Results are presented comparing model simulations to instability inception data of an eleven stage, high pressure ratio compressor operating at part-power, and the results analyzed in the context of linear modal analysis.

The application of compound proportional resonant control strategy in multiple PV inverters system

2018 ◽  
Vol 32 (34n36) ◽  
pp. 1840098
Author(s):  
Yuan Li ◽  
Huifang Shen ◽  
Chao Xiong ◽  
Yaofei Han ◽  
Guofeng He
Keyword(s):  
Control Strategy ◽  
Closed Loop ◽  
Control Strategies ◽  
Integrated Control ◽  
Reference Signal ◽  
Loop Model ◽  
Harmonic Compensation ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Set Up

In order to eliminate the effect on the grid current caused by the background harmonic voltage and the reference signal on the grid connected multi-inverter, this paper adopts the double closed-loop feed-forward control strategy. This strategy is based on the inductor voltage and the grid-connected current, and the integrated control strategy of quasi-proportional resonance loop parallel to a specific harmonic compensation loop. Based on the closed-loop model of multiple inverters, the change curves of the transfer function of the two control strategies are compared with the feed-forward control and the composite proportional resonance. The two corresponding control methods are used to analyze the current quality of the multi-inverter impact. Finally, the MATLAB/Simulink simulation model is set up to verify the proposed control strategies. The simulation results show that the proposed method can achieve better tracking of the sinusoidal command signal at the fundamental frequency, and enhance the anti-interference ability of the system at the 3rd, 5th, and 7th harmonic frequency.

scholarly journals A New Active Control Strategy for Pantograph in High-Speed Electrified Railways Based on Multi-Objective Robust Control

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 173719-173730 ◽  
Author(s):  
Jing Zhang ◽  
Hantao Zhang ◽  
Baolin Song ◽  
Songlin Xie ◽  
Zhigang Liu
Keyword(s):  
Robust Control ◽  
Active Control ◽  
Control Strategy ◽  
High Speed ◽  
Multi Objective ◽  
Active Control Strategy ◽  
Electrified Railways

The Measurement and Interpretation of Flow within Rotating Stall Cells in Axial Compressors

1978 ◽  
Vol 20 (2) ◽  
pp. 101-114 ◽  
Author(s):  
I. J. Day ◽  
N.A. Cumpsty
Keyword(s):  
Flow Direction ◽  
Axial Flow ◽  
Tangential Direction ◽  
Rotating Stall ◽  
Design Flow ◽  
Flow Measurements ◽  
Axial Compressors ◽  
Multi Stage ◽  
Wide Range ◽  
Flow Compressor

Detailed flow measurements obtained by a new measuring technique are presented for the flow in a stalled axial-flow compressor. Results were obtained from a wide range of compressor builds, including multi-stage and single-stage configurations of various design flow rates and degrees of reaction. Instantaneous recordings of absolute velocity, flow direction and total and static pressures have been included for both full-span and part-span stall. With the aid of these results, it has been shown that the conventional model of the flow in a stall cell is erroneous. An alternative model is proposed, based on the observation that the fluid must cross from one side of the cell to the other in order to preserve continuity in the tangential direction. An investigation of the experimental results also reveals the finer details of the flow in the cell and shows how these details are related to the design flow rate of the compressor. The influence of these cell details on the power absorbed by a stalled compressor are investigated, and consideration is given to the complex pressure patterns encountered in the compressor.

Fuzzy Semi-Active Control of Multi-Degree-of-Freedom Structure Using Magnetorheological Elastomers

2017 ◽  
Author(s):  
Nguyen Xuan Bao ◽  
Toshihiko Komatsuzaki ◽  
Yoshio Iwata ◽  
Haruhiko Asanuma
Keyword(s):  
Active Control ◽  
Control Strategy ◽  
Control Strategies ◽  
Excitation Frequency ◽  
Harmonic Excitation ◽  
Effective Control ◽  
Magnetic Flux Density ◽  
Model Parameters ◽  
Structural Vibrations ◽  
Standard Linear Solid

Magnetorheological elastomer (MRE), used in semi-active control, has recently emerged as a smart material that could potentially improve traditional systems in controlling structural vibrations. This study considers two main issues concerning the application of an MRE. The first issue is the modelling and identification of the viscoelastic property, and the second is the formulation of an effective control strategy based on the fuzzy logic system. Firstly, a nonlinear dynamic MRE model was developed to simulate the dynamic behavior of MRE. In this model, the viscoelastic force of the material as an output was calculated from displacement, frequency, and magnetic flux density as inputs. The MRE model consisted of three components including the viscoelasticity of host elastomer, magnetic field-induced property, and interfacial slippage that were modeled by analogy with a standard linear solid model (Zener model), a stiffness variable spring, and a smooth Coulomb friction, respectively. The model parameters were identified by manipulating two sets of data that were measured by changing applied electric current and harmonic excitation frequency. A good agreement was obtained between numerical and experimental results. The proposed model offers a beneficial solution to numerically investigate vibration control strategies. Secondly, a fuzzy semi-active controller was designed for seismic protection of building with an MRE-based isolator. The control strategy was designed to determine the command applied current. The proposed strategy is fully adequate to the nonlinearity of the isolator and works independently with the building structure. The efficiency of the proposed fuzzy semi-active controller was investigated numerically by MATLAB simulations, whose performance was compared with that of passive systems and a system with traditional semi-active controller. Numerical results show that the developed fuzzy semi-active controller not only mitigates the responses of both the base floor and the superstructure, but also has an ability to control structural vibrations adaptively to the different intensity ground motions.

Rotating Stall Observations in a High Speed Compressor—Part II: Numerical Study

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
J. Dodds ◽  
M. Vahdati
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Axial Flow ◽  
Leading Edge ◽  
Rotating Stall ◽  
Tip Clearance ◽  
Tip Clearance Flow ◽  
Numerical Predictions ◽  
Stage 1 ◽  
Variable Stator

In this two-part paper the phenomenon of part span rotating stall is studied. The objective is to improve understanding of the physics by which stable and persistent rotating stall occurs within high speed axial flow compressors. This phenomenon is studied both experimentally (Part I) and numerically (Part II). The experimental observations reported in Part I are now explored through the use of 3D unsteady Reynolds-averaged Navier–Stokes (RANS) simulation. The objective is to both validate the computational model and, where possible, explore some physical aspects of the phenomena. Unsteady simulations are presented, performed at a fixed speed with the three rows of variable stator vanes adjusted to deliberately mismatch the front stages and provoke stall. Two families of rotating stall are identified by the model, consistent with experimental observations from Part I. The first family of rotating stall originates from hub corner separations developing on the stage 1 stator vanes. These gradually coalesce into a multicell rotating stall pattern confined to the hub region of the stator and its downstream rotor. The second family originates from regions of blockage associated with tip clearance flow over the stage 1 rotor blade. These also coalesce into a multicell rotating stall pattern of shorter length scale confined to the leading edge tip region. Some features of each of these two patterns are then explored as the variable stator vanes (VSVs) are mismatched further, pushing each region deeper into stall. The numerical predictions show a credible match with the experimental findings of Part I. This suggests that a RANS modeling approach is sufficient to capture some important aspects of part span rotating stall behavior.

High Speed Compressor Surge With Application to Active Control

1990 ◽  
Author(s):  
A. M. Cargill ◽  
C. Freeman
Keyword(s):  
Active Control ◽  
Blast Wave ◽  
High Speed ◽  
High Amplitude ◽  
Rotating Stall ◽  
Effective Control ◽  
Small Scale ◽  
Compressor Surge ◽  
Aero Engines ◽  
Global Type

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.

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