Download or read book Wide range Robust Control of Combustion Instabilities written by Boe-Shong Hong and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wide Range Robust Control of Combustion Instability written by Boe-Shong Hong and published by . This book was released on 2001 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents the concept and design of a two-layer robust control system for suppression of combustion instabilities over a wide range of operation. The control law synthesis based on a multiple-time-scale model of combustion dynamics. Control actions on the fast-time scale are provided by secondary fuel injection realized as modulation of the primary fuel flow and are gain-scheduled according to the variations of mean-flow temperature and velocity on the slow-time scale. A linear parameter varying (LPV) L2 -gain control law is formulated in the setting of differential generic theory. Simulation experiments have been conducted to evaluate the control law under wide-range operation of a generic combustor in terms of the trade-off among: (i) fuel injection rate and pressure oscillation: (ii) transient and steady responses: and (iii) stability robustness and performance.
Download or read book Robust Feedback Control of Combustion Instability with Model Uncertainty written by B. S. Hong and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Adaptive Robust Control Systems written by Anh Tuan Le and published by BoD – Books on Demand. This book was released on 2018-03-07 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the applications of robust and adaptive control approaches to practical systems. The proposed control systems hold two important features: (1) The system is robust with the variation in plant parameters and disturbances (2) The system adapts to parametric uncertainties even in the unknown plant structure by self-training and self-estimating the unknown factors. The various kinds of robust adaptive controls represented in this book are composed of sliding mode control, model-reference adaptive control, gain-scheduling, H-infinity, model-predictive control, fuzzy logic, neural networks, machine learning, and so on. The control objects are very abundant, from cranes, aircrafts, and wind turbines to automobile, medical and sport machines, combustion engines, and electrical machines.
Download or read book CHARACTERIZATION OF COMBUSTION INSTABILITY IN A MODIFIED RIJKE TUBE FOR OPTIMAL EXPERIMENTAL DESIGN written by Evan Jay Dillen and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion instability, or the coupling between acoustic oscillations and heat release rate fluctuations, is one of the most expensive problems facing power generation gas turbines today. The push to produce power with fewer emissions and increased cycling requirements brought on by alternative energy sources have made operating conditions prone to combustion instability more prevalent and in need of effective control measures. The potential solution for controlling these instabilities is active control systems, but a robust, active control system has not yet been developed for implementation on a full scale system.Key to developing such a system is model parameter estimation. Without accurate model parameters, active control cannot be done. This thesis details the design, construction, and data acquisition capability of a modified Rijke tube built by the author for this investigation. The thermoacoustic behavior of the Rijke tube is mapped as a function of co-flow velocity and flame height. Sensitivity to system parameters is investigated. The results of the instability mapping and sensitivity analysis are used to inform the optimal experimental design. Finally, optimal experimental design for estimation of combustion model parameters of a linear time-delay thermoacoustic instability model is performed and results discussed.
Download or read book Robust Control written by Moises Rivas-Lopez and published by BoD – Books on Demand. This book was released on 2016-07-06 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need to be tolerant to changes in the control systems or in the operational environment of systems subject to unknown disturbances has generated new control methods that are able to deal with the non-parametrized disturbances of systems, without adapting itself to the system uncertainty but rather providing stability in the presence of errors bound in a model. With this approach in mind and with the intention to exemplify robust control applications, this book includes selected chapters that describe models of H-infinity loop, robust stability and uncertainty, among others. Each robust control method and model discussed in this book is illustrated by a relevant example that serves as an overview of the theoretical and practical method in robust control.
Download or read book Lean Combustion written by Derek Dunn-Rankin and published by Academic Press. This book was released on 2011-07-28 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion under sufficiently fuel-lean conditions can have the desirable attributes of high efficiency and low emissions, this being particularly important in light of recent and rapid increases in the cost of fossil fuels and concerns over the links between combustion and global climate change. Lean Combustion is an eminently authoritative, reference work on the latest advances in lean combustion technology and systems. It will offer engineers working on combustion equipment and systems both the fundamentals and the latest developments in more efficient fuel usage and in much-sought-after reductions of undesirable emissions, while still achieving desired power output and performance. This volume brings together research and design of lean combustion systems across the technology spectrum in order to explore the state-of-the-art in lean combustion and its role in meeting current and future demands on combustion systems. Readers will learn about advances in the understanding of ultra lean fuel mixtures and how new types of burners and approaches to managing heat flow can reduce problems often found with lean combustion such as slow, difficult ignition and frequent flame extinction. The book will also offer abundant references and examples of recent real-world applications. Covers all major recent developments in lean combustion science and technology, with new applications in both traditional combustion schemes as well as such novel uses as highly preheated and hydrogen-fueled systems Offers techniques for overcoming difficult ignition problems and flame extinction with lean fuel mixtures Covers new developments in lean combustion using high levels of pre-heat and heat re-circulating burners, as well as the active control of lean combustion instabilities
Download or read book Combustion Instabilities in Gas Turbine Engines written by Timothy C. Lieuwen and published by AIAA (American Institute of Aeronautics & Astronautics). This book was released on 2005 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers gas turbine users and manufacturers a valuable resource to help them sort through issues associated with combustion instabilities. In the last ten years, substantial efforts have been made in the industrial, governmental, and academic communities to understand the unique issues associated with combustion instabilities in low-emission gas turbines. The objective of this book is to compile these results into a series of chapters that address the various facets of the problem. The Case Studies section speaks to specific manufacturer and user experiences with combustion instabilities in the development stage and in fielded turbine engines. The book then goes on to examine The Fundamental Mechanisms, The Combustor Modeling, and Control Approaches.
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 Gasoline Compression Ignition Technology written by Gautam Kalghatgi and published by Springer Nature. This book was released on 2022-01-17 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on gasoline compression ignition (GCI) which offers the prospect of engines with high efficiency and low exhaust emissions at a lower cost. A GCI engine is a compression ignition (CI) engine which is run on gasoline-like fuels (even on low-octane gasoline), making it significantly easier to control particulates and NOx but with high efficiency. The state of the art development to make GCI combustion feasible on practical vehicles is highlighted, e.g., on overcoming problems on cold start, high-pressure rise rates at high loads, transients, and HC and CO emissions. This book will be a useful guide to those in academia and industry.
Download or read book Thermoacoustic Instability written by R. I. Sujith and published by Springer Nature. This book was released on 2021-12-14 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book systematically presents the consolidated findings of the phenomenon of self-organization observed during the onset of thermoacoustic instability using approaches from dynamical systems and complex systems theory. Over the last decade, several complex dynamical states beyond limit cycle oscillations such as quasiperiodicity, frequency-locking, period-n, chaos, strange non-chaos, and intermittency have been discovered in thermoacoustic systems operated in laminar and turbulent flow regimes. During the onset of thermoacoustic instability in turbulent systems, an ordered acoustic field and large coherent vortices emerge from the background of turbulent combustion. This emergence of order from disorder in both temporal and spatiotemporal dynamics is explored in the contexts of synchronization, pattern formation, collective interaction, multifractality, and complex networks. For the past six decades, the spontaneous emergence of large amplitude, self-sustained, tonal oscillations in confined combustion systems, characterized as thermoacoustic instability, has remained one of the most challenging areas of research. The presence of such instabilities continues to hinder the development and deployment of high-performance combustion systems used in power generation and propulsion applications. Even with the advent of sophisticated measurement techniques to aid experimental investigations and vast improvements in computational power necessary to capture flow physics in high fidelity simulations, conventional reductionist approaches have not succeeded in explaining the plethora of dynamical behaviors and the associated complexities that arise in practical combustion systems. As a result, models and theories based on such approaches are limited in their application to mitigate or evade thermoacoustic instabilities, which continue to be among the biggest concerns for engine manufacturers today. This book helps to overcome these limitations by providing appropriate methodologies to deal with nonlinear thermoacoustic oscillations, and by developing control strategies that can mitigate and forewarn thermoacoustic instabilities. The book is also beneficial to scientists and engineers studying the occurrence of several other instabilities, such as flow-induced vibrations, compressor surge, aeroacoustics and aeroelastic instabilities in diverse fluid-mechanical environments, to graduate students who intend to apply dynamical systems and complex systems approach to their areas of research, and to physicists who look for experimental applications of their theoretical findings on nonlinear and complex systems.
Download or read book Feedback Control of Combustion Instabilities written by Anil Gulati and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1987 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling and Control of Thermoacoustics in a One dimensional Combustor written by Xiaoling Chen and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation examines the model-based optimization of sensor placement, estimation, and control for the active suppression of thermoacoustic instabilities in a one-dimensional combustor. This research is motivated by the increasing use of lean premixed combustion for emission reduction in gas turbine combustors. Thermoacoustic instability is a potentially damaging side effect of lean premixed combustion, caused by the unstable coupling between acoustics and unsteady heat release. There is extensive existing literature on the suppression of this instability, using both passive means such as Helmholtz resonators and active stability control. Much of the work on active combustion stability control relies on the injection of an additional acoustic excitation or fuel supply to break the above undesirable unstable coupling, thereby suppressing instability. Researchers have shown the promise of active combustion instability control both in simulations and laboratory experiments, for both single and multiple modes of instability. Active combustion stability control remains relatively scarce in industrial practice, despite the rich existing literature indicating its potential for success. Several important research questions need to be answered in order to help bridge this gap. First, while much of the recent research on active combustion stability control assumes one-dimensional combustion dynamics, an open question remains regarding the importance of other dynamic effects in the combustor, such as the dynamic interactions between multiple flames. Second, the degree to which the placement of sensors and actuators in a combustor affects the accuracy with which combustion instability dynamics can be estimated remains relatively unexplored in the literature. Third, the suitability of traditional linear model-based estimation and control techniques for stabilizing combustion instabilities with nonlinear heat release dynamics also remains relatively unexplored in the literature. The overarching goal of this dissertation is to address the above gaps using a combination of optimal sensor placement, optimal estimation, and optimal control. Towards this goal, the dissertation makes six specific contributions to the literature: 1. First, the author performs an experimental comparison between thermoacoustic instabilities in single- versus multi-nozzle combustion systems (Chapter 2). This study shows that the dynamic interactions between multiple flames in a multi-nozzle combustor have a non-trivial impact on thermoacoustic instability, especially the time scales of the transient instabilities. This helps characterize and understand the constraints on the practical applicability of one-dimensional combustion instability models for multi-nozzle systems, including the models used in the remainder of this dissertation. 2. Second, the author optimizes the design of a laboratory characterization experiment for a one-dimensional combustor (Chapter 3). This optimization utilizes Fisher information analysis for optimal combustion instability characterization, for the first time. 3. Third, the dissertation shows, using a mix of simulation-based and experimental studies, that the above use of optimal experimental design improves combustion instability parameterization accuracy (Chapter 4). Moreover, by furnishing more accurate combustion instability models, one is able to achieve higher levels of confidence in the robustness of the resulting combustion stability controllers. 4. Fourth, the dissertation presents a novel algorithm that makes it possible to estimate combustion heat release rates from multi-microphone measurements of the resulting acoustic signatures, in a manner that does not require the modeling of heat release dynamics (Chapter 5). This is important because it simplifies the online estimation of heat release dynamics, compared to model-based estimation methods requiring a heat release model. 5. Fifth, the dissertation studies the impact of sensor placement on the observability and LQG control of combustion instabilities governed by a linear $n-\tau$ heat release model (Chapter 6). This work highlights the importance of placing acoustic sensors at specific locations like the pressure mode anti-node points, including the acoustically closed combustor boundary. 6. Finally, the author develops a computational framework for the co-simulation of linear combustor acoustics, model-based combustion stability control, and nonlinear heat release dynamics governed by a level-set solver (Chapter 7). To the best of the author's knowledge, this is the first framework in the literature enabling the simulation-based study of the efficacy of linear control for combustion instabilities characterized by nonlinear heat release dynamics. In making the above contributions to the literature, this dissertation builds on the well-established idea that linear model-based estimation and control can be effective in suppressing combustion instability. The novelty of the dissertation lies in: 1. Pushing the above idea further by examining the degree to which its efficacy can be enhanced further through the use of information theory to optimize sensor placement and experimental design for estimation/control applications. 2. Building a framework that makes it possible to study the efficacy of model-based linear estimation/control in the context of thermo-acoustic instabilities driven by nonlinear heat release dynamics.
Download or read book Feedback Control of Oscillations in Combustion and Cavity Flows written by Simon J. Illingworth and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis considers the control of combustion oscillations, motivated by the susceptibility of lean premixed combustion to such oscillations, and the long and expensive development and commissioning times that this is giving rise to. The controller used is both closed-loop, employing an actuator to modify some system parameter in response to a measured signal, and adaptive, meaning that it is able to maintain control over a wide range of operating conditions. The controller is applied to combustion systems with annular geometries, where instabilities can occur both longitudinally and azimuthally, and which require multiple sensors and multiple actuators for control. One of the requirements of Lyapunov-based adaptive control which is particularly troublesome for combustion systems is then addressed: that the sign of the high-frequency gain of the open-loop system is known. We address it by using an adaptive controller which employs a Nussbaum gain, and successfully apply it experimentally to combustion oscillations in a Rijke tube. Another type of fluid-acoustic resonance is then considered: the compressible flow past a shallow cavity. We start by finding a linear model of the cavity flow's dynamics, or its `transfer function', which we identify from direct numerical simulations. We compare this measured transfer function to that given by a conceptual model which is based on the Rossiter mechanism, and which models each component of the flow physics separately. We then look at using closed-loop control to eliminate these cavity oscillations. We start by designing a robust $\mathcal{H}-2$ controller based on a balanced reduced order model of the system, the model being provided by the Eigensystem Realization Algorithm (ERA). The robust controller provides closed-loop stability over a much wider Mach number range than seen in previous studies. Finally, we look at the suitability of the adaptive controller, earlier developed for combustion oscillations, for the cavity. Based on some general properties of the cavity flow, and by using collocated control, the oscillations are eliminated at all Mach numbers tested in the range $0.4 \le M \le 0.8$.
