Active control of combustion instabilities

Demonstration of Active Control of Combustion Instabilities on a Full-Scale Gas Turbine Combustor

Volume 2: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations ◽

10.1115/2001-gt-0519 ◽

2001 ◽

Cited By ~ 14

Author(s):

C. E. Johnson ◽

Y. Neumeier ◽

M. Neumaier ◽

B. T. Zinn ◽

D. D. Darling ◽

...

Keyword(s):

Gas Turbine ◽

Active Control ◽

Fast Response ◽

Dominant Mode ◽

Broadband Noise ◽

Full Scale ◽

Operating Conditions ◽

Combustion Instabilities ◽

Gas Turbine Combustor ◽

Airflow Distribution

This paper presents the results of an investigation of active control of combustion instabilities in a natural gas, high-pressure, full-scale gas turbine combustor that was retrofitted with an Active Control System (ACS). The combustor test rig simulates the geometry, inlet airflow distribution, and pressurization of a can-type combustor that exhibits dynamic flame instabilities at some off-design operating conditions. Two essential features of the investigated ACS are 1) a real-time mode observer that identified the frequencies, amplitudes and phases of the dominant modes in the pressure signal and 2) a fast response servo valve that can modulate a large portion of the gaseous fuel. Two active control configurations were studied. In the first configuration, the actuator was mounted on one of two premixed fuel stages, and in the second configuration it was mounted on the inlet to the stabilizing diffusion stage. In both configurations, the ACS damped combustion instabilities, attenuating the dominant mode by up to 15dB and reducing the overall broadband noise by 30-40%. NOx emissions were also reduced by approximately 10% when control was applied. Finally, this study demonstrated the importance of having a fast multiple-mode observer when dealing with complex combustion processes with inherently large time delays.

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Smart Combustors: Just Around the Corner

Volume 2: Turbo Expo 2005 ◽

10.1115/gt2005-69138 ◽

2005 ◽

Cited By ~ 4

Author(s):

Ben T. Zinn

Keyword(s):

Control System ◽

Control Systems ◽

Gas Turbine ◽

Active Control ◽

Health Monitoring ◽

State Of The Art ◽

The State ◽

Research Needs ◽

Combustion Instabilities ◽

Lean Blowout

This paper reviews the state of the art of active control systems (ACS) for gas turbine combustors. Specifically, it discusses the manner in which ACS can improve the performance of combustors, the architecture of such ACS, and the designs and promising performance of ACS that have been developed to control combustion instabilities, lean blowout and pattern factor. The paper closes with a discussion of research needs, with emphasis on the integration of utilized engine ACS, health monitoring and prognostication systems into a single control system that could survive in the harsh combustor environment.

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Suppression of Instabilities in Gaseous Fuel High-Pressure Combustor Using Non-Coherent Oscillatory Fuel Injection

Volume 2: Turbo Expo 2003 ◽

10.1115/gt2003-38103 ◽

2003 ◽

Cited By ~ 7

Author(s):

D. Shcherbik ◽

E. Lubarsky ◽

Y. Neumeier ◽

B. T. Zinn ◽

K. McManus ◽

...

Keyword(s):

High Pressure ◽

Active Control ◽

Fuel Injection ◽

Injection Rate ◽

Open Loop ◽

Combustion Instabilities ◽

Open Loop Control ◽

Pressure Oscillations ◽

Loop Control ◽

Fuel Injection Rate

This paper describes the application of active, open loop, control in effective damping of severe combustion instabilities in a high pressure (i.e., around 520 psi) gas turbine combustor simulator. Active control was applied by harmonic modulation of the fuel injection rate into the combustor. The open-loop active control system consisted of a pressure sensor and a fast response actuating valve. To determine the dependence of the performance of the active control system upon the frequency, the fuel injection modulation frequency was varied between 300 and 420 Hz while the frequency of instability was around 375 Hz. These tests showed that the amplitude of the combustor pressure oscillations strongly depended upon the frequency of the open loop control. In fact, the amplitude of the combustor pressure oscillations varied ten fold over the range of investigated frequencies, indicating that applying the investigated open loop control approach at the appropriate frequency could effectively damp detrimental combustion instabilities. This was confirmed in subsequent tests in which initiation of open loop modulation of the fuel injection rate at a non resonant frequency of 300Hz during unstable operation with peak to peak instability amplitude of 114 psi and a frequency of 375Hz suppressed the instability to a level of 12 psi within approximately 0.2 sec (i.e., 75 periods). Analysis of the time dependence of the spectra of the pressure oscillations during suppression of the instability strongly suggested that the open loop fuel injection rate modulation effectively damped the instability by “breaking up” (or preventing the establishment of) the feedback loop between the reaction rate and combustor oscillations that drove the instability.

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Combustor Model for Simulation of Combustion Instabilities and Their Active Control

Journal of Propulsion and Power ◽

10.2514/2.5594 ◽

2000 ◽

Vol 16 (3) ◽

pp. 485-491 ◽

Cited By ~ 6

Author(s):

Rajendran Mohanraj ◽

Yedidia Neumeier ◽

Ben T. Zinn

Keyword(s):

Active Control ◽

Combustion Instabilities

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Sub-Scale Demonstration of the Active Feedback Control of Gas-Turbine Combustion Instabilities

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.483204 ◽

2000 ◽

Vol 122 (2) ◽

pp. 262-268 ◽

Cited By ~ 31

Author(s):

Stanley S. Sattinger ◽

Yedidia Neumeier ◽

Aharon Nabi ◽

Ben T. Zinn ◽

David J. Amos ◽

...

Keyword(s):

Control System ◽

Feedback Control ◽

Gas Turbine ◽

Active Control ◽

Combustion Instabilities ◽

Engine Operation ◽

Turbine Engine ◽

Control Approach ◽

Active Feedback ◽

Active Feedback Control

Described are sub-scale tests that successfully demonstrate active feedback control as a means of suppressing damaging combustion oscillations in natural-gas-fueled, lean-premix combustors. The control approach is to damp the oscillations by suitably modulating an auxiliary flow of fuel injected near the flame. The control system incorporates state observer software that can ascertain the frequency, amplitude, and phase of the dominant modes of combustion oscillation, and a sub-scale fuel flow modulator that responds to frequencies well above 1 kHz. The demonstration was conducted on a test combustor that could sustain acoustically coupled combustion instabilities at preheat and pressurization conditions approaching those of gas-turbine engine operation. With the control system inactive, two separate instabilities occurred with combined amplitudes of pressure oscillations exceeding 70 kPa (10 psi). The active control system produced four-fold overall reduction in these amplitudes. With the exception of an explainable control response limitation at one frequency, this reduction represented a major milestone in the implementation of active control. [S0742-4795(00)00702-X]

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Active Control of Combustion Instability in a Liquid–Fueled Sector Combustor

Volume 2: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations ◽

10.1115/99-gt-215 ◽

1999 ◽

Cited By ~ 28

Author(s):

J. R. Hibshman ◽

J. M. Cohen ◽

A. Banaszuk ◽

T. J. Anderson ◽

H. A. Alholm

Keyword(s):

Active Control ◽

Combustion Instability ◽

Full Scale ◽

Instability Mode ◽

Combustion Instabilities ◽

Fuel Flow ◽

Lean Premixed

A system for the active control of combustion instabilities in liquid-fueled, lean, premixed combustors was demonstrated in a three-nozzle sector combustor, using full-scale engine hardware. Modulation of a portion of the premixed fuel flow led to a reduction of 6.5 dB (2.1X) in the amplitude of the dominant instability mode. Combustor emissions were not adversely affected by the control.

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