Download or read book Tuned Passive Control of Combustion Instabilities written by Dan Zhao and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Actively tuned Passive Control of Combustion Instabilities written by Chuan-Han Wang and published by . This book was released on 2004 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 Passive control of combustion instability in lean premixed combustors ASME 99 GT 52 written by Robert C. Steele and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented at the International Gas Turbine & Aeroengine Congress & Exhibition, Indianapolis, Indiana, June 7-June 10, 1999.
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 An Experimental Study of the Effect of a Pilot Flame on Technically Pre mixed Self excited Combustion Instabilities written by Bridget O'meara and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion instabilities are a problem facing the gas turbine industry in the operation of lean, pre-mixed combustors. Secondary flames known as "pilot flames" are a common passive control strategy for eliminating combustion instabilities in industrial gas turbines, but the underlying mechanisms responsible for the pilot flame's stabilizing effect are not well understood. This dissertation presents an experimental study of a pilot flame in a single-nozzle, swirl-stabilized, variable length atmospheric combustion test facility and the effect of the pilot on combustion instabilities. A variable length combustor tuned the acoustics of the system to excite instabilities over a range of operating conditions without a pilot flame. The inlet velocity was varied from 25 -- 50 m/s and the equivalence ratio was varied from 0.525 -- 0.65. This range of operating conditions was determined by the operating range of the combustion test facility. Stability at each operating condition and combustor length was characterized by measurements of pressure oscillations in the combustor. The effect of the pilot flame on the magnitude and frequency of combustor stability was then investigated. The mechanisms responsible for the pilot flame effect were studied using chemiluminescence flame images of both stable and unstable flames. Stable flame structure was investigated using stable flame images of CH* chemiluminescence emission. The effect of the pilot on stable flame metrics such as flame length, flame angle, and flame width was investigated. In addition, a new flame metric, flame base distance, was defined to characterize the effect of the pilot flame on stable flame anchoring of the flame base to the centerbody. The effect of the pilot flame on flame base anchoring was investigated because the improved stability with a pilot flame is usually attributed to improved flame anchoring through the recirculation of hot products from the pilot to the main flame base.Chemiluminescence images of unstable flames were used to identify several instability mechanisms and infer how these mechanisms are affected by the pilot flame. Flame images of cases in which the pilot flame did not eliminate the instability were investigated to understand why the pilot flame is not effective in certain cases. The phase of unstable pilot flame oscillations was investigated to determine how the phase of pilot flame oscillations may affect its ability to interfere with instability mechanisms in the main flame. A forced flame response study was conducted to determine the effect of inlet velocity oscillation amplitude on the pilot flame. The flame response was characterized by measurements of velocity oscillations in the injector and chemiluminescence intensity oscillations determined from flame images. As the forcing amplitude increases, the pilot flame's effect on the flame transfer function magnitude becomes weaker. Flame images show that as the forcing amplitude increases, the pilot flame oscillations increase, leading to an ineffective pilot. The results of the flame response portion of this study highlight the effect of instability amplitude on the ability of a pilot flame to eliminate a combustion instability.
Download or read book An Experimental Study of the Effect of a Pilot Flame on Combustion Instabilities written by Jihang Li and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Lean-premixed gas turbines, due to their superior emission performance, have been widely used in the industry. However, lean-premixed combustion is susceptible to combustion instability, which has become a major concern in the design and operation of lean-premixed gas turbines. Passive secondary flames, also known as pilot flames, are commonly used for control of combustion instability. However, the underlying mechanism whereby a pilot flame suppresses combustion instability is not fully understood. This limits the improvement of pilot systems.This dissertation presents an experimental study on the effect of a pilot flame on combustion instabilities in an atmospheric, laboratory-scale, single-nozzle, swirl-stabilized, lean-premixed combustor. The pilot flame is a central jet flame injected from the centerbody, which can operate in either the technically-premixed or the fully-premixed modes, depending on the types of pilot injectors. Piezoelectric sensors are utilized to measure the pressure fluctuation and the velocity fluctuation. High speed CH* chemiluminescence techniques are used to measure the dynamics of the flame. The instability characteristics of the technically-premixed unpiloted flame are measured at varying combustor length. Four distinct instability modes with different frequencies are observed. A one-dimensional simulation is conducted to calculate the natural frequencies and mode shapes of the instabilities. The effect of varying the percent pilot of a technically-premixed pilot flame on the technically-premixed combustion instabilities in different modes is studied. Instability maps to the percent pilot and the overall equivalence ratio are presented and discussed. The instability boundaries in each instability map, which separates the unstable regions from the stable regions, are discussed in detail by analyzing the high-speed images and Rayleigh index images. The results show that the pilot flame affects the main flame dynamics primarily through enhancing flame attachment and flame oscillation in the inner shear layer. The effect of independently varying the pilot air, pilot fuel and pilot mixture flow rates on the technically-premixed combustion instabilities are studied by utilizing a modified pilot injector. The results show that the effect of the pilot flame on the combustion instability is primarily determined by the equivalence ratio, but not the mixture flow rate of the pilot flame. The results support the statement that pilot flames influence the main flame dynamics by heat recirculation and demonstrate that the effect of the pilot flame is determined by its ability to change the time-averaged recirculation zone temperature. The structures of the pilot flame are presented and discussed.Fully-premixed flame transfer functions under the influence of a premixed pilot flame are investigated. The flame transfer functions show distinct behaviors at low frequencies and high frequencies. At low frequencies, the pilot flame has a weak effect on the FTF gain and phase, while at high frequencies, increasing the percent pilot reduces the FTF gain and shifts the FTF phase. High-speed chemiluminescence images show the pilot flame enhances the fluctuation near the base of the flame, which enhances the destructive interference within the inner shear layer, reduces the FTF gain and shifts the FTF phase at high frequencies. By separating the flame transfer function into different regions, it was found that a pilot flame only influences the inner shear layer, but not the near-wall region and the outer recirculation zone.
Download or read book An Overview of Active Control of Combustion Instabilities written by B. T. Zinn 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 Active Control of Combustion Instabilities written by and published by . This book was released on 2001 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Active Control of Combustion Instabilities written by Daniel Clay Allgood and published by . This book was released on 2001 with total page 312 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:
Download or read book System Design Methods for Simultaneous Optimal Control of Combustion Instabilities and Efficiency written by and published by . This book was released on 2002 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work under this contract primarily involved the design, analysis and testing of control algorithms aimed at the suppression of thermoacoustic instabilities and the optimization of combustor performance. Three different types of algorithms were considered in this work: Pattern search, explicit gradient, and least-mean-square based feedback, which we have designated filtered-E. The algorithms are listed in order of increasing speed and increasing amount of a priori information required. Both pattern search and explicit gradient algorithms are useful for the optimization of combustion performance as well as the suppression of thermoacoustic instabilities. Filtered-E is intended solely for the fast suppression of thermoacoustic instabilities. All of the algorithms were successful in suppressing thermoacoustic instabilities in an experimental combustor. In addition, we provide an analysis of the mechanism for achieving control using on-off actuators pulsed subharmonically, validate the analysis with experimental results and propose a variable- subharmonic controller. Control systems using on-off actuation can be adaptively tuned using pattern search or explicit gradient algorithms with little modification. The filtered-E algorithm has also been effective when applied to on-off actuation, even though the implicit gradient is not quite correct.
Download or read book Suppression of Combustion Instabilities by Active Control written by T. Poinsot and published by . This book was released on 1987 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Premixed Flames written by Nedunchezhian Swaminathan and published by Cambridge University Press. This book was released on 2011-04-25 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: A work on turbulent premixed combustion is important because of increased concern about the environmental impact of combustion and the search for new combustion concepts and technologies. An improved understanding of lean fuel turbulent premixed flames must play a central role in the fundamental science of these new concepts. Lean premixed flames have the potential to offer ultra-low emission levels, but they are notoriously susceptible to combustion oscillations. Thus, sophisticated control measures are inevitably required. The editors' intent is to set out the modeling aspects in the field of turbulent premixed combustion. Good progress has been made on this topic, and this cohesive volume contains contributions from international experts on various subtopics of the lean premixed flame problem.
Download or read book Active Control of Combustion Instabilities written by Nidal Al-Masoud and published by . This book was released on 2002 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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:
