Active control of the field scattered by the rigid wall of a semi-anechoic room - Simulations and full-scale off-line experiment

2021 ◽  
pp. 116134
Author(s):  
C. Pinhède ◽  
D. Habault ◽  
E. Friot ◽  
Ph. Herzog
Keyword(s):  
Active Control ◽  
Rigid Wall ◽  
Full Scale

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

2001 ◽  
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.

Full‐Scale Implementation of Active Control. I: Design and Simulation

1991 ◽  
Vol 117 (11) ◽  
pp. 3516-3536 ◽  
Author(s):  
T. T. Soong ◽  
A. M. Reinhorn ◽  
Y. P. Wang ◽  
R. C. Lin
Keyword(s):  
Active Control ◽  
Full Scale

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

1999 ◽  
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.

Active Control of Pressure Oscillations in a Liquid-Fueled Sector Combustor

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
J. M. Cohen ◽  
A. Banaszuk ◽  
J. R. Hibshman ◽  
T. J. Anderson ◽  
H. A. Alholm
Keyword(s):  
Active Control ◽  
Full Scale ◽  
Pressure Oscillations ◽  
Fuel Flow ◽  
Lean Premixed

A system for the active control of combustor pressure oscillations 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 (2.1 times) in the amplitude of the dominant pressure oscillations mode. Combustor emissions were not adversely affected by the control.

Active control in civil engineering: From conception to full scale applications

2001 ◽  
Vol 8 (2) ◽  
pp. 123-178 ◽  
Author(s):  
M. Aupérin ◽  
C. Dumoulin ◽  
G. E. Magonette ◽  
F. Marazzi ◽  
H. Försterling ◽  
...  
Keyword(s):  
Active Control ◽  
Civil Engineering ◽  
Full Scale

Flight Validation of a System for Autonomous Rotorcraft Multilift

2019 ◽  
Vol 64 (3) ◽  
pp. 1-13
Author(s):  
Marc D. Takahashi ◽  
Matthew S. Whalley ◽  
Marcos G. Berrios ◽  
Gregory J. Schulein
Keyword(s):  
Active Control ◽  
Flight Test ◽  
Maximum Load ◽  
Full Scale ◽  
Test Results

A system for rotorcraft dual lift was developed and flight-tested using two Yamaha RMAX helicopters equipped with customized avionics and sling–load hardware. Important features of the system were tested, including precision dual-lift maneuvering, load tension equalization, and load motion damping. Flight-test results are presented that include autonomous takeoff and landing and an oval racetrack pattern flying at 5 m/s carrying 171% of the rated maximum load for one aircraft. Results of formation changes while flying oval patterns are also presented as well as results on active control to equalize the sling tensions between the two aircraft. In addition, sling–load feedback results to increase the sling damping in hover are presented. Finally, the feasibility of migrating the concept to full-scale is shown in simulation using two UH-60 models in a dual-lift configuration carrying 6000 lb at 80 kt.

Full‐Scale Implementation of Active Control. II: Installation and Performance

1993 ◽  
Vol 119 (6) ◽  
pp. 1935-1960 ◽  
Author(s):  
A. M. Reinhorn ◽  
T. T. Soong ◽  
M. A. Riley ◽  
R. C. Lin ◽  
S. Aizawa ◽  
...  
Keyword(s):  
Active Control ◽  
Full Scale ◽  
And Performance

Active Control of the Acoustic Boundary Conditions of Combustion Test Rigs: Extension to Actuators With Non-Linear Response

2009 ◽  
Author(s):  
Mirko R. Bothien ◽  
Christian Oliver Paschereit
Keyword(s):  
Boundary Conditions ◽  
Active Control ◽  
Linear Response ◽  
Full Scale ◽  
Operating Conditions ◽  
Test Rig ◽  
Acoustic Boundary Conditions ◽  
Control Scheme ◽  
Resonance Frequencies ◽  
Non Linear

In the design process, new burners are generally tested in combustion test rigs. With these experiments, as well as with CFD, finite element calculations, and low-order network models, the burner’s performance in the full-scale engine is sought to be predicted. Especially, information about the thermoacoustic behaviour and the emissions is very important. As the thermoacoustics strongly depend on the acoustic boundary conditions of the system, it is obvious that test rig conditions should match or be close to those of the full-scale engine. This is, however, generally not the case. Hence, if the combustion process in the test rig is stable at certain operating conditions, it may show unfavourable dynamics at the same conditions in the engine. In previous works, the authors introduced an active control scheme which is able to mimic almost arbitrary acoustic boundary conditions. Thus, the test rig properties can be tuned to correspond to those of the full-scale engine. The acoustic boundary conditions were manipulated using woofers. In the present study, an actuator with higher control authority is investigated, which could be used to apply the control scheme in industrial test rigs. The actuator modulates an air mass flow to generate an acoustic excitation. However, in contrast to the woofers, it exhibits a strong non-linear response regarding amplitude and frequency. Thus, the control scheme is further developed to account for these non-linear transfer characteristics. This modified control scheme is then applied to change the acoustic boundary conditions of an atmospheric swirl-stabilized combustion test rig. Excellent results were obtained in terms of changing the reflection coefficient to different levels. By manipulating its phase, different resonance frequencies could be imposed without any hardware changes. The non-linear control approach is not restricted to the actuator used in this study and might therefore be of use for other actuators as well.

Tuning of the Acoustic Boundary Conditions of Combustion Test Rigs With Active Control: Extension to Actuators With Nonlinear Response

2010 ◽  
Vol 132 (9) ◽  
Author(s):  
Mirko R. Bothien ◽  
Christian Oliver Paschereit
Keyword(s):  
Boundary Conditions ◽  
Active Control ◽  
Nonlinear Response ◽  
Combustion Process ◽  
Full Scale ◽  
Operating Conditions ◽  
Test Rig ◽  
Acoustic Boundary Conditions ◽  
Control Scheme ◽  
Resonance Frequencies

In the design process, new burners are generally tested in combustion test rigs. With these experiments, as well as with computational fluid dynamics, finite element calculations, and low-order network models, the burner’s performance in the full-scale engine is sought to be predicted. Especially, information about the thermoacoustic behavior and the emissions is very important. As the thermoacoustics strongly depend on the acoustic boundary conditions of the system, it is obvious that test rig conditions should match or be close to those of the full-scale engine. This is, however, generally not the case. Hence, if the combustion process in the test rig is stable at certain operating conditions, it may show unfavorable dynamics at the same conditions in the engine. In previous works, the authors introduced an active control scheme, which is able to mimic almost arbitrary acoustic boundary conditions. Thus, the test rig properties can be tuned to correspond to those of the full-scale engine. The acoustic boundary conditions were manipulated using woofers. In the present study, an actuator with higher control authority is investigated, which could be used to apply the control scheme in industrial test rigs. The actuator modulates an air mass flow to generate an acoustic excitation. However, in contrast to the woofers, it exhibits a strong nonlinear response regarding amplitude and frequency. Thus, the control scheme is further developed to account for these nonlinear transfer characteristics. This modified control scheme is then applied to change the acoustic boundary conditions of an atmospheric swirl-stabilized combustion test rig. Excellent results were obtained in terms of changing the reflection coefficient to different levels. By manipulating its phase, different resonance frequencies could be imposed without any hardware changes. The nonlinear control approach is not restricted to the actuator used in this study and might therefore be of use for other actuators as well.

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