Download or read book Active Control of Combustion Instabilities in Gas Turbine Engines for Low Emissions Part II Adaptive Control Algorithm Development Demonstration and Performance Limitations written by Andrzej Banaszuk and published by . This book was released on 2001 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present results of experiment with two distinct extremum-seeking adaptive algorithms for control of combustion instability suitable for reduction of acoustic pressure oscillations in gas turbine over large range of operating conditions. The algorithms consists of a frequency tracking Extended Kalman Filter to determine the in-phase component, the quadrature component, and the magnitude of the acoustic mode of interest, and a phase shifting controller with the controller phase tuned using an extremum-seeking algorithms. The algorithms are also applicable for control of oscillations of systems whose oscillation frequency and optimal control phase shift depends on operating conditions, and which are driven by strong broad-band disturbance. The algorithms have been tested in combustion experiments involving full-scale engine hardware and during simulated fast engine transients.

Download or read book Applied Combustion Diagnostics written by Katharina Kohse-Hoinghaus and published by CRC Press. This book was released on 2002-04-26 with total page 734 pages. Available in PDF, EPUB and Kindle. Book excerpt: The editors have assembled a world-class group of contributors who address the questions the combustion diagnostic community faces. They are chemists who identify the species to be measured and the interfering substances that may be present; physicists, who push the limits of laser spectroscopy and laser devices and who conceive suitable measuremen

Download or read book Thermoacoustic Combustion Instability Control written by Dan Zhao and published by Academic Press. This book was released on 2023-02-13 with total page 1145 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoacoustic Combustion Instability Control: Engineering Applications and Computer Codes provides a unique opportunity for researchers, students and engineers to access recent developments from technical, theoretical and engineering perspectives. The book is a compendium of the most recent advances in theoretical and computational modeling and the thermoacoustic instability phenomena associated with multi-dimensional computing methods and recent developments in signal-processing techniques. These include, but are not restricted to a real-time observer, proper orthogonal decomposition (POD), dynamic mode decomposition, Galerkin expansion, empirical mode decomposition, the Lattice Boltzmann method, and associated numerical and analytical approaches. The fundamental physics of thermoacoustic instability occurs in both macro- and micro-scale combustors. Practical methods for alleviating common problems are presented in the book with an analytical approach to arm readers with the tools they need to apply in their own industrial or research setting. Readers will benefit from practicing the worked examples and the training provided on computer coding for combustion technology to achieve useful results and simulations that advance their knowledge and research. Focuses on applications of theoretical and numerical modes with computer codes relevant to combustion technology Includes the most recent modeling and analytical developments motivated by empirical experimental observations in a highly visual way Provides self-contained chapters that include a comprehensive, introductory section that ensures any readers new to this topic are equipped with required technical terms

Download or read book Real Time Optimization by Extremum Seeking Control written by Kartik B. Ariyur and published by John Wiley & Sons. This book was released on 2003-10-03 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: An up-close look at the theory behind and application of extremum seeking Originally developed as a method of adaptive control for hard-to-model systems, extremum seeking solves some of the same problems as today's neural network techniques, but in a more rigorous and practical way. Following the resurgence in popularity of extremum-seeking control in aerospace and automotive engineering, Real-Time Optimization by Extremum-Seeking Control presents the theoretical foundations and selected applications of this method of real-time optimization. Written by authorities in the field and pioneers in adaptive nonlinear control systems, this book presents both significant theoretic value and important practical potential. Filled with in-depth insight and expert advice, Real-Time Optimization by Extremum-Seeking Control: * Develops optimization theory from the points of dynamic feedback and adaptation * Builds a solid bridge between the classical optimization theory and modern feedback and adaptation techniques * Provides a collection of useful tools for problems in this complex area * Presents numerous applications of this powerful methodology * Demonstrates the immense potential of this methodology for future theory development and applications Real-Time Optimization by Extremum-Seeking Control is an important resource for both students and professionals in all areas of engineering-electrical, mechanical, aerospace, chemical, biomedical-and is also a valuable reference for practicing control engineers.

Download or read book Control of Fluid Flow written by Petros Koumoutsakos and published by Springer. This book was released on 2010-04-06 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph presents the state of the art of theory and applications in fluid flow control, assembling contributions by leading experts in the field. The book covers a wide range of recent topics including vortex based control algorithms, incompressible turbulent boundary layers, aerodynamic flow control, control of mixing and reactive flow processes or nonlinear modeling and control of combustion dynamics.

Download or read book Active Control of Combustion Instabilities in Gas Turbine Engines for Low Emissions Part I Physics Based and Experimentally Identified Models of Combustion Instability written by C. A. Jacobson and published by . This book was released on 2000 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper details the development of a thermoacoustic model and associated dynamic analysis. The model describes the results obtained in a gas fueled experimental combustion program carried out at UTRC. The contents of the paper are (a) the development of a thermoacoustic model composed of acoustic and heat release components, (b) the dynamic analysis of the resulting non-linear model using harmonic balance methods to compute linear stability boundaries and the amplitudes of oscillations and (c) the calibration of the model to experimental data.

Download or read book Active Combustion Control for Aircraft Gas Turbine Engines written by and published by . This book was released on 2000 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiparameter Extremum Seeking and Applications to Propulsion and Aerodynamics Problems written by Kartik Balasubramanian Ariyur and published by . This book was released on 2002 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Validation of an Adaptive Combustion Instability Control Method for Gas Turbine Engines written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-20 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes ongoing testing of an adaptive control method to suppress high frequency thermo-acoustic instabilities like those found in lean-burning, low emission combustors that are being developed for future aircraft gas turbine engines. The method called Adaptive Sliding Phasor Averaged Control, was previously tested in an experimental rig designed to simulate a combustor with an instability of about 530 Hz. Results published earlier, and briefly presented here, demonstrated that this method was effective in suppressing the instability. Because this test rig did not exhibit a well pronounced instability, a question remained regarding the effectiveness of the control methodology when applied to a more coherent instability. To answer this question, a modified combustor rig was assembled at the NASA Glenn Research Center in Cleveland, Ohio. The modified rig exhibited a more coherent, higher amplitude instability, but at a lower frequency of about 315 Hz. Test results show that this control method successfully reduced the instability pressure of the lower frequency test rig. In addition, due to a certain phenomena discovered and reported earlier, the so called Intra-Harmonic Coupling, a dramatic suppression of the instability was achieved by focusing control on the second harmonic of the instability. These results and their implications are discussed, as well as a hypothesis describing the mechanism of intra-harmonic coupling. Kopasakis, George and DeLaat, John C. and Chang, Clarence T. Glenn Research Center NASA/TM-2004-213198, AIAA Paper 2004-4028, E-14698

Download or read book Active Control of High Frequency Combustion Instability in Aircraft Gas Turbine Engines written by and published by . This book was released on 2003 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Active Control of Combustion and Its Applicatons written by A. J. Moran and published by . This book was released on 2001 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ducted flame in any of its forms can have the tendency to interact with its surroundings. When this interaction takes the form of thermo-acoustic instabilities the consequences can be grave. These instabilities have been recognised as a problem for many decades and have appeared in many forms of engine including rocket motors, ramjets, main engine gas turbine combustors and after burning system. It is true to say that the phenomena has not been truly understood and that many researchers have come up with several theories as to how these thermo-acoustic instabilities occur. In the field of engineering, the ability to fix the problem rather than fully understand the problem has been a principle that has been applied for many years. The approaches taken to fixing thermo-acoustic, problems have been either radical re-design of the combustion system or the application of passive damping techniques. In the past decade, however, a further technique has been given to the combustion designer, that technique being the ability to use active control. This paper outlines how the technique has been developed, from small scale pilot rig testing through to full engine demonstration, and how active control may be applied to land-based gas turbines in the future. With the introduction of ultra low emission lean pre-mixed combustion systems to land based gas turbines the propensity to exhibit thermo-acoustic instabilities has increased. Actively controlling the instability is a real option, the benefits of gaining extensive experience with the technology on land will help to promote the technology for future application to aircraft.

Download or read book Towards Verifiable Adaptive Control of Gas Turbine Engines written by Mehrdad Pakmehr and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation investigates the problem of developing verifiable stable control architectures for gas turbine engines. First, a nonlinear physics-based dynamic model of a twin spool turboshaft engine which drives a variable pitch propeller is developed. In this model, the dynamics of the engine are defined to be the two spool speeds, and the two control inputs to the system are fuel flow rate and prop pitch angle. Experimental results are used to verify the dynamic model of JetCat SPT5 turboshaft engine. Based on the experimental data, performance maps of the engine components including propeller, high pressure compressor, high pressure, and low pressure turbines are constructed. The engine numerical model is implemented using Matlab. Second, a stable gain scheduled controller is described and developed for a gas turbine engine that drives a variable pitch propeller. A stability proof is developed for a gain scheduled closed-loop system using global linearization and linear matrix inequality (LMI) techniques. Using convex optimization tools, a single quadratic Lyapunov function is computed for multiple linearizations near equilibrium and non-equilibrium points of the nonlinear closed-loop system. This approach guarantees stability of the closed-loop gas turbine engine system. To verify the stability of the closed-loop system on-line, an optimization problem is proposed which is solvable using convex optimization tools. Through simulations, we show the developed gain scheduled controller is capable to regulate a turboshaft engine for large thrust commands in a stable fashion with proper tracking performance. Third, a gain scheduled model reference adaptive control (GS-MRAC) concept for multi-input multi-output (MIMO) nonlinear plants with constraints on the control inputs is developed and described. Specifically, adaptive state feedback for the output tracking control problem of MIMO nonlinear systems is studied. Gain scheduled reference model system is used for generating desired state trajectories, and the stability of this reference model is also analyzed using convex optimization tools. This approach guarantees stability of the closed-loop gain scheduled gas turbine engine system, which is used as a gain scheduled reference model. An adaptive state feedback control scheme is developed and its stability is proven, in addition to transient and steady-state performance guarantees. The resulting closed-loop system is shown to have ultimately bounded solutions with a priori adjustable bounded tracking error. The results are then extended to GS-MRAC with constraints on the magnitudes of multiple control inputs. Sufficient conditions for uniform boundedness of the closed-loop system is derived. A semi-global stability result is proven with respect to the level of saturation for open-loop unstable plants, while the stability result is shown to be global for open-loop stable plants. Simulations are performed for three different models of the turboshaft engine, including the nominal engine model and two models where the engine is degraded. Through simulations, we show the developed GS-MRAC architecture can be used for the tracking problem of degraded turboshaft engine for large thrust commands with guaranteed stability. Finally, a decentralized linear parameter dependent representation of the engine model is developed, suitable for decentralized control of the engine with core and fan/prop subsystems. Control theoretic concepts for decentralized gain scheduled model reference adaptive control (D-GS-MRAC) systems is developed. For each subsystem, a linear parameter dependent model is available and a common Lyapunov matrix can be computed using convex optimization tools. With this control architecture, the two subsystems of the engine (i.e., engine core and engine prop/fan) can be controlled with independent controllers for large throttle commands in a decentralized manner. Based on this D-GS-MRAC architecture, a "plug and play" (PnP) technology concept for gas turbine engine control systems is investigated, which allows us to match different engine cores with different engine fans/propellers. With this plug and play engine control architecture, engine cores and fans/props could be used with their on-board subordinate controllers ready for integration into a functional propulsion system. Simulation results for three different models of the engine, including the nominal engine model, the model with a new prop, and the model with a new engine core, illustrate the possibility of PnP technology development for gas turbine engine control systems.

Download or read book Adaptive Control of Combution Instabilities Using Real time Modes Observation written by Clifford Edgar Johnson and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion instabilities are a significant problem in combustion systems, particularly in Low NOx Gas Turbine combustors. These instabilities result in large-scale pressure oscillations in the combustor, leading to degraded combustor performance, shortened lifetime, and catastrophic combustor failure. The objective of this research was to develop a practical adaptive active control system that, coupled with an appropriate actuator, is capable of controlling the combustor pressure oscillations without a priori knowledge of the combustor design, operating conditions or instability characteristics. The adaptive controller utilizes an observer that determines the frequencies, phases and amplitudes of the dominant modes of the oscillations in real time. The research included development and testing of the adaptive controller on several combustors and on an unstable acoustic feedback system in order to analyze its performance. The research also included investigations of combustor controllability and combustor stability margin, which are critical issues for practical implementation of an active control system on an industrial combustor. The results of this research are directly applicable to a variety of combustors and can be implemented on full-scale industrial combustion systems.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1990 with total page 996 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Causes of Combustion Instabilities with Passive and Active Methods of Control for Practical Application to Gas Turbine Engines written by Michael D. Cornwell and published by . This book was released on 2011 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion at high pressure in applications such as rocket engines and gas turbine engines commonly experience destructive combustion instabilities. These instabilities results from interactions between combustion heat release, fluid mechanics and acoustics. This research explores the significant affect of unstable fluid mechanics processes in augmenting unstable periodic combustion heat release. The frequency of the unstable heat release may shift to match one of the combustors natural acoustic frequencies which then can result in significant energy exchange from chemical to acoustic energy resulting in thermoacoustic instability. The mechanisms of the fluid mechanics in coupling combustion to acoustics are very broad with many varying mechanisms explained in detail in the first chapter. Significant effort is made in understanding these mechanisms in this research in order to find commonalities, useful for mitigating multiple instability mechanisms. The complexity of combustion instabilities makes mitigation of combustion instabilities very difficult as few mitigation methods have historically proven to be very effective for broad ranges of combustion instabilities. This research identifies turbulence intensity near the forward stagnation point and movement of the forward stagnation point as a common link in what would otherwise appear to be very different instabilities. The most common method of stabilization of both premixed and diffusion flame combustion is through the introduction of swirl. Reverse flow along the centerline is introduced to transport heat and chemically active combustion products back upstream to sustain combustion. This research develops methods to suppress the movement of the forward stagnation point without suppressing the development of the vortex breakdown process which is critical to the transport of heat and reactive species necessary for flame stabilization. These methods are useful in suppressing the local turbulence at the forward stagnation point, limiting dissipation of heat and reactive species significantly improving stability. Combustion hardware is developed and tested to demonstrate the stability principles developed as part of this research. In order to more completely understand combustion instability a very unique method of combustion was researched where there are no discrete points of combustion initiation such as the forward stagnation point typical in many combustion systems including swirl and jet wake stabilized combustion. This class of combustion which has empirical evidence of great stability and efficient combustion with low CO, NOx and UHC emissions is described as high oxidization temperature distributed combustion. This mechanism of combustion is shown to be stable largely because there are no stagnations points susceptible to fluid mechanic perturbations. The final topic of research is active combustion control by fuel modulation. This may be the only practical method of controlling most instabilities with a single technique. As there are many papers reporting active combustion control algorithms this research focused on the complexities of the physics of fuel modulation at frequencies up to 1000 Hz with proportionally controlled flow amplitude. This research into the physics of high speed fluid movement, oscillation mechanical mechanisms and electromagnetics are demonstrated by development and testing of a High Speed Latching Oscillator Valve.

Download or read book An Adaptive Instability Suppression Controls Method for Aircraft Gas Turbine Engine Combustors written by George Kopasakis and published by BiblioGov. This book was released on 2013-07 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: An adaptive controls method for instability suppression in gas turbine engine combustors has been developed and successfully tested with a realistic aircraft engine combustor rig. This testing was part of a program that demonstrated, for the first time, successful active combustor instability control in an aircraft gas turbine engine-like environment. The controls method is called Adaptive Sliding Phasor Averaged Control. Testing of the control method has been conducted in an experimental rig with different configurations designed to simulate combustors with instabilities of about 530 and 315 Hz. Results demonstrate the effectiveness of this method in suppressing combustor instabilities. In addition, a dramatic improvement in suppression of the instability was achieved by focusing control on the second harmonic of the instability. This is believed to be due to a phenomena discovered and reported earlier, the so called Intra-Harmonic Coupling. These results may have implications for future research in combustor instability control.

Download or read book Reduced order Modeling and Active Control of Dry low emission Combustion written by Tongxun Yi and published by . This book was released on 2007 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation is a complementary experimental and theoretical investigation of combustion instability and lean blowout (LBO) in dry-low-emission (DLE) gas turbine engines, aiming to understand the fundamental mechanisms and shed light on active combustion control.