Local L2 Gain of Axial Flow Compressor Control

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Tiebao Yang ◽  
Xiang Chen
Keyword(s):  
Axial Flow ◽  
Pressure Rise ◽  
Engine Performance ◽  
Rotating Stall ◽  
Robust Controller ◽  
Stabilizing Controllers ◽  
Stable Operating ◽  
Flow Compressor ◽  
Hamilton Jacobi Bellman ◽  
L2 Gain

Feedback control has been pursued to stabilize the bifurcated operating solution near the rotating stall point in axial-flow compressors. These controllers can extend the stable operating range and hence improve engine performance. However, the local L2 gain of these controllers still remains unknown. In this paper, a family of Lyapunov functions is first constructed, and then the local L2 gain is derived through Hamilton–Jacobi–Bellman inequality for a class of stabilizing controllers with throttle position as actuator and pressure rise as measurement. The results obtained in this paper provide useful guidance for selecting the most robust controller from a given class of stabilizing controllers in terms of L2 gain.

scholarly journals Robustness of Rotating Stall Control for Axial-Flow Compressors*

2003 ◽  
Vol 125 (3) ◽  
pp. 424-428 ◽  
Author(s):  
Ali Tahmasebi ◽  
Xiang Chen
Keyword(s):  
Axial Flow ◽  
Engine Performance ◽  
Rotating Stall ◽  
Stabilizing Controllers ◽  
Stable Operating ◽  
Uncertainty Set ◽  
The Stability ◽  
Stall Control ◽  
Admissible Uncertainty ◽  
Axial Flow Compressors

Feedback control has been pursued to address the rotating stall problem in axial flow compressors in order to extend the stable operating range and to improve engine performance. These controllers guarantee the stability of the bifurcated operating solution near the stall point. In this paper, an analytic approach is developed to characterize the robustness of some stabilizing controllers for rotating stall in axial-flow compressors. The numerical examples show that the size of the admissible uncertainty set changes for stabilizing controllers with different feedback gains. It is also proved that a nonlinear stabilizing control is not necessarily superior to a linear one.

Numerical Results for Axial Flow Compressor Instability

1989 ◽  
Vol 111 (4) ◽  
pp. 434-441 ◽  
Author(s):  
F. E. McCaughan
Keyword(s):  
Guide Vane ◽  
Axial Flow ◽  
Pressure Rise ◽  
Companion Paper ◽  
Extensive Study ◽  
Rotating Stall ◽  
Numerical Results ◽  
Flow Diagram ◽  
Inlet Guide Vane ◽  
Flow Compressor

Using Cornell’s supercomputing facilities, we have carried out an extensive study of the Moore–Greitzer model, which gives accurate and reliable information about compressor instability. The bifurcation analysis in the companion paper shows the dependence of the mode of compressor response on the shape of the rotating stall characteristic. The numerical results verify and extend this with a more accurate representation of the characteristic. The effect of the parameters on the shape of the rotating stall characteristic is investigated, and it is found that the parameters with the strongest effects are the inlet length, and the shape of the compressor pressure rise versus mass flow diagram (i.e., tall diagrams versus shallow diagrams). We also discuss the effects of inlet guide vane loss on the characteristic. An evaluation is made of the h′ = −g approximation, and a spectral analysis of the rotating stall cell given by the full model suggests why this breaks down.

scholarly journals A Review of Recent Research on Contra-Rotating Axial Flow Compressor Stage

1996 ◽  
Author(s):  
P. B. Sharma ◽  
A. Adekoya
Keyword(s):  
Axial Flow ◽  
Pressure Rise ◽  
Rotating Stall ◽  
Flow Capacity ◽  
Through Flow ◽  
Theoretical Investigations ◽  
Aero Engines ◽  
Flow Compressor ◽  
The Stability ◽  
Future Work

Aero compressor technology has seen a significant advancement during the last two decades. Research on Rotor-Stator stage has focused on improvements in the design as well as off-design performance. Work has also been carried out to improve the clearance losses, stage loading as well as the stability of the operation. In this connection, the work on end-bend rotor-stator and variable geometry stators is specially significant. These efforts have however, yielded marginal improvements as far as the capability of the stage to produce pressure rise and its through-flow capacity are concerned. The interest in contra-rotation has emerged with a view to achieve considerable high pressure rise per stage besides its effects on stability of the stage to rotating stall/surge suppression. Contra-rotation concept has already found its acceptability in the development of future fuel efficient gas turbine plants and aero engines. This paper presents a review of the experimental and theoretical investigations on the aero-dynamic and aero-acoustic performance of the contra-rotating pressure stage. The areas of future work on contra-rotation are also outlined.

Application of Bifurcation Theory to Axial Flow Compressor Instability

1989 ◽  
Vol 111 (4) ◽  
pp. 426-433 ◽  
Author(s):  
F. E. McCaughan
Keyword(s):  
Parameter Space ◽  
Bifurcation Theory ◽  
Qualitative Difference ◽  
Axial Flow ◽  
Complete Information ◽  
Rotating Stall ◽  
Numerical Work ◽  
System Parameters ◽  
Parametric Effects ◽  
Flow Compressor

When a compression system becomes unstable, the mode of response depends on the operating and system parameters, such as throttle setting and B parameter. Previous numerical work on the model developed by Moore and Greitzer has provided a limited picture of the parametric effects. Applying bifurcation theory to a single-harmonic version of the model has supplied much more complete information, defining the boundaries of each mode of response in the parameter space. Specifically this is shown in a plot of B versus throttle setting, which compares well with the corresponding map produced experimentally. We stress the importance of the shape of the rotating stall characteristic. The analysis shows the qualitative difference between classic surge and deep surge.

scholarly journals A 3D Rotating Stall Stability Model for Axial Flow Compressor

1997 ◽  
Author(s):  
Ren-Jing Cao ◽  
Sheng Zhou
Keyword(s):  
Axial Flow ◽  
Rotating Stall ◽  
3D Flow ◽  
Aerodynamic Stability ◽  
Stall Margin ◽  
Spatial Variables ◽  
Stability Behavior ◽  
Stability Model ◽  
Flow Effects ◽  
Flow Compressor

Rotating stall phenomenon is usually characterized by 3D aerodynamic stability behavior. The earlier models mainly considered the flow effects in terms of 1D and 2D spatial variables. In order to involve the characteristics of the 3D flow of the compressor, it is necessary to improve the existing rotating stall stability models and further develop the models to consider the effects of the 3D disturbance. In this paper, a new aerodynamic stability model concerning the effects of a radial disturbance produced by the compressor, and explaining more mechanisms about the aerodynamic stability of compressor is presented. Using the developed rotating stall stability model, the stall margins are calculated and compared to experimental data for two axial flow compressors. The calculated results show that the developed 3D rotating stall stability model gives better stall margin prediction than that by the 2D model.

Distributed Control of Rotating Stall in an Axial Flow Compressor With Actuator Constraints

2000 ◽  
Author(s):  
Craig A. Buhr ◽  
Matthew A. Franchek ◽  
Sanford Fleeter
Keyword(s):  
Absolute Stability ◽  
Closed Loop ◽  
Axial Flow ◽  
Gain Control ◽  
Rotating Stall ◽  
Control Law ◽  
Circle Criterion ◽  
Axial Flow Compressor ◽  
Flow Compressor ◽  
Stall Control

Abstract Presented in this paper is an analytical study evaluating the closed loop stability of rotating stall control in an axial flow compressor subject to a nonlinear spatial actuation constraint that limits the amplitude of a spatial mode input. Absolute stability of the rotating stall control system is investigated by applying the circle criterion to a linearized model of an axial compressor in series with the saturation element. This stability analysis is then used to design the gain and phase of the ‘classical’ complex gain feedback control law. Resulting is a systematic method for designing the parameters of the complex gain control law which increases the region of absolute stability guaranteed by the circle criterion for the closed-loop system.

scholarly journals 3D Flow Field Measurement Around a Rotating Stall Cell

1998 ◽  
Author(s):  
C. Palomba ◽  
P. Puddu ◽  
F. Nurzia
Keyword(s):  
Flow Field ◽  
Axial Flow ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Field Pattern ◽  
Mean Flow ◽  
Axial Section ◽  
Average Technique ◽  
Compressor Rotor ◽  
Flow Compressor

Rotating stall is an unsteady phenomenon that arises in axial and radial flow compressors. Under certain operating conditions a more or less regular cell of turbulent flow develops and propagates around the annulus at a speed lower than rotor speed. Recently little work has been devoted to the understanding of the flow field pattern inside a rotating cell. However, this knowledge could be of help in the understanding of the interaction between the cell and the surrounding flow. Such information could be extremely important during the modelling process when some hypothesis have to be made about the cell behaviour. A detailed experimental investigation has been conducted during one cell operation of an isolated low-speed axial flow compressor rotor using a slanted hot wire and an ensemble average technique based on the cell revolution time. The three flow field components have been measured on 9 axial section for 800 circumferential points and on 21 radial stations to give a complete description of the flow field upstream and downstream of the rotor. Interpretation of data can give a description of the mean flow field patterns inside and around the rotating cell.

Influence of Rain Ingestion on the Endwall Treatment in an Axial Flow Compressor

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Jichao Li ◽  
Juan Du ◽  
Mingzhen Li ◽  
Feng Lin ◽  
Hongwu Zhang ◽  
...  
Keyword(s):  
Rotor Blade ◽  
Axial Flow ◽  
Pressure Rise ◽  
Water Film ◽  
Stall Margin ◽  
Axial Flow Compressor ◽  
Water Ingestion ◽  
Blade Row ◽  
Flow Compressor ◽  
The Stability

The effects of water ingestion on the performance of an axial flow compressor are experimentally studied with and without endwall treatment. The background to the work is derived from the assessment of airworthiness for an aero-engine. The stability-enhancing effects with endwall treatments under rain ingestion are not previously known. Moreover, all the endwall treatments are designed under dry air conditions in the compressor. Water ingestion at 3% and 5% relative to the design mass flow proposed in the airworthiness standard are applied to initially investigate the effects on the performance under smooth casing (SC). Results show that the water ingestions are mainly located near the casing wall after they move through the rotor blade row. The pressure rise coefficient increases, efficiency declines, and torque increases under the proposed water ingestion. The increase of the inlet water increases the thickness of the water film downstream the rotor blade row and aggravates the adverse effects on the performances. Subsequently, three endwall treatments, namely circumferential grooves, axial slots, and hybrid slots–grooves, are tested with and without water ingestion. Compared with no water ingestion, the circumferential grooves basically have no resistance to the water ingestion. The axial slots best prevent the drop of the pressure rise coefficient induced by water ingestion, and hybrid slots–grooves are the second-best place owing to the contribution of the front axial slots. Therefore, the hybrid slots–grooves can not only extend the stall margin with less efficiency penalty compared with axial slots, but also prevent rain ingestion from worsening the compressor performance.

Experimental Investigation on the Effect of Porosity of Bend Skewed Casing Treatment on a Single Stage Transonic Axial Flow Compressor

2014 ◽  
Author(s):  
Dilipkumar B. Alone ◽  
Subramani Satish Kumar ◽  
Shobhavathy Thimmaiah ◽  
Janaki Rami Reddy Mudipalli ◽  
A. M. Pradeep ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Axial Flow ◽  
Compressor Stage ◽  
Casing Treatment ◽  
Operating Range ◽  
Axial Flow Compressor ◽  
Transonic Compressor ◽  
Stable Operating ◽  
Flow Compressor ◽  
Casing Treatments

A bend skewed casing treatment was designed, to study the influence of one of its geometrical parameter porosity on the stable performance of single stage transonic axial flow compressor. The compressor was designed for the stage total-to-total pressure ratio of 1.35, corrected mass flow rate of 22 kg/s at corrected design speed of 12930 RPM. Bend skewed casing treatment has an axial inlet segment till 50% of the total length and rear segment that is skewed by 45° in the direction of the rotor tip section stagger. Both the sections were oriented at a skew angle of 45° to the radial plane such that the flow exiting the slot is in counter-clockwise direction to that of the rotor direction. The casing treatment slot width was equal to the maximum thickness of the rotor blades. Three casing treatment configurations were identified for the current experimental investigation. All the treatment geometries considered for the experimental research have lower porosities than reported in the open literatures. The effect of the porosity parameter on the performance of transonic compressor stage was evaluated at two axial coverages of 20% and 40% relative to the rotor tip axial chord. Performance maps were obtained for the solid casing and casing treatment with three different porosities. Comparative studies were carried out and experimental results showed a maximum of 65% improvement in the stable operating range of the compressor for one of the treatment configurations. It was also observed that the stable operating range of the compressor increases with an increase in the casing treatment porosity. All the casing treatment configurations showed that the compressor stall occurs at lower mass flows as compared to the solid casing. Compressor stage peak efficiency shows significant degradations with increase in the porosity as compared to solid casing. Detailed blade element performances were also obtained using calibrated multi-hole aerodynamic probe. Comparative variations of flow parameters like absolute flow angle, Mach number were studied at full flow and near stall conditions for the solid casing and casing treatment configurations. Hot wire measurements show very high fluctuation in the inlet axial velocity in the presence of solid casing as compared to casing treatments. Experimental investigation revealed that the porosity of the casing treatments has strong influence on the transonic compressor stage performance.

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.

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