Download or read book A Combustor Model for Control oriented Simulation of Combustion Instabilities written by Rajendran Mohanraj and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation and Active Control of Combustion Instability in a Ramjet Combustor written by S. Menon and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Characterization and Simulation of the Thermoacoustic Instability Behavior of an Advanced Low Emissions Combustor Prototype written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2019-01-13 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extensive research is being done toward the development of ultra-low-emissions combustors for aircraft gas turbine engines. However, these combustors have an increased susceptibility to thermoacoustic instabilities. This type of instability was recently observed in an advanced, low emissions combustor prototype installed in a NASA Glenn Research Center test stand. The instability produces pressure oscillations that grow with increasing fuel/air ratio, preventing full power operation. The instability behavior makes the combustor a potentially useful test bed for research into active control methods for combustion instability suppression. The instability behavior was characterized by operating the combustor at various pressures, temperatures, and fuel and air flows representative of operation within an aircraft gas turbine engine. Trends in instability behavior versus operating condition have been identified and documented, and possible explanations for the trends provided. A simulation developed at NASA Glenn captures the observed instability behavior. The physics-based simulation includes the relevant physical features of the combustor and test rig, employs a Sectored 1-D approach, includes simplified reaction equations, and provides time-accurate results. A computationally efficient method is used for area transitions, which decreases run times and allows the simulation to be used for parametric studies, including control method investigations. Simulation results show that the simulation exhibits a self-starting, self-sustained combustion instability and also replicates the experimentally observed instability trends versus operating condition. Future plans are to use the simulation to investigate active control strategies to suppress combustion instabilities and then to experimentally demonstrate active instability suppression with the low emissions combustor prototype, enabling full power, stable operation. DeLaat, John C. and Paxson, Daniel E. Glenn Research Cent

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 A Sectored One Dimensional Model for Simulating Combustion Instabilities in Premix Combustors written by Daniel E. Paxson and published by . This book was released on 1999 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Longitudinal Mode Combustion Instabilities Modeling and Experiments written by and published by . This book was released on 2000 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling and Simulation of Combustion Chamber and Propellant Dynamics and Issues in Active Control of Combustion Instabilities written by Giorgio C. Isella and published by . This book was released on 2001 with total page 342 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 A Sectored One Dimensional Model for Simulating Combustion Instabilities in Premix Combustors written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-15 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A one-dimensional, CFD based combustor simulation has been developed that exhibits self-excited, thermoacoustic oscillations in premixed combustor geometries that typically have large, abrupt changes in cross sectional area. The combustor geometry is approximated by dividing it into a finite number of one-dimensional sectors. Within each sector, the equations of motion are integrated numerically, along with a species transport and a reaction equation. Across the sectors, mass and energy are conserved, and momentum loss is prescribed using appropriately compatible boundary conditions that account for the area change. The resulting simulation and associated boundary conditions essentially represent a one-dimensional, multi-block technique. Details of the simulation code are presented herein. Results are then shown comparing experimentally observed and simulated operation of a particular combustor rig that exhibited different instabilities at different operating points. It will be shown that the simulation closely matched the rig data in oscillation amplitudes, frequencies, and operating points at which the instabilities occurred. Finally, advantages and limitations of the simulation technique are discussed. Paxson, Daniel E. Glenn Research Center NASA/TM-1999-209771, NAS 1.15:209771, AIAA Paper 2000-0313, E-12051

Download or read book Predicton of Combustion Driven Dynamic Instability for High Performance Gas Turbine Combustors written by B. Sekar and published by . This book was released on 2001 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes the development and application of a combined detailed three-dimensional large eddy simulation (LES) and one-dimensional analysis tool to predict and actively control combustion-driven dynamic instabilities in gas turbine combustors. The integration of detailed finite-rate kinetics into LES and use of In-situ Adaptive Tabulation (ISAT) to efficiently calculate multi-species finite-rate kinetics in LES along with the use of global kinetics in the one-dimensional analysis tool was demonstrated. The results showed that LES can be effectively used to simulate complex reacting flows in gas turbine combustors and to identify regions of combustion instabilities. The results also showed that the one-dimensional combustor analysis with global kinetics can then be used both to capture the combustor unstable modes of the predicted regions of instabilities and to actively control these instabilities. In particular, the results demonstrated that by modulating the primary fuel injection rates and the time-lag between the instant of fuel-air mixture injection and heat release, damping out the instabilities may be achieved.

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 Unsteady Combustor Physics written by Tim C. Lieuwen and published by Cambridge University Press. This book was released on 2012-08-27 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developing clean, sustainable energy systems is a pre-eminent issue of our time. Most projections indicate that combustion-based energy conversion systems will continue to be the predominant approach for the majority of our energy usage. Unsteady combustor issues present the key challenge associated with the development of clean, high-efficiency combustion systems such as those used for power generation, heating or propulsion applications. This comprehensive study is unique, treating the subject in a systematic manner. Although this book focuses on unsteady combusting flows, it places particular emphasis on the system dynamics that occur at the intersection of the combustion, fluid mechanics and acoustic disciplines. Individuals with a background in fluid mechanics and combustion will find this book to be an incomparable study that synthesises these fields into a coherent understanding of the intrinsically unsteady processes in combustors.

Download or read book Modeling and Control of Combustion Instability written by Jean-Pierre Hathout and published by . This book was released on 2000 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Combustion Instabilities written by Claude Seywert and published by . This book was released on 2001 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Active Control of Combustion Instabilities with Real time Observation of Unstable Combustor Modes written by Y. Neumeier and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: