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Dissertations / Theses on the topic 'Combustion Acoustic'

Author: Grafiati

Published: 4 June 2021

Last updated: 6 February 2022

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1

Botura, César Augusto [UNESP]. "Desenvolvimento de um sistema de incineração de resíduos sólidos para utilização com combustão pulsante." Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/106449.

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Made available in DSpace on 2014-06-11T19:35:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-11Bitstream added on 2014-06-13T20:27:54Z : No. of bitstreams: 1 botura_ca_dr_guara.pdf: 4170323 bytes, checksum: 21316bd955d294e528bc1edcbfa2bd8b (MD5)<br>Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)<br>Universidade Estadual Paulista (UNESP)<br>Este trabalho tem a finalidade de investigar a incineração de resíduos sólidos na presença de ondas acústicas para incrementar o processo de combustão. Para tanto foi projetado e construído um forno rotativo para incineração de resí

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2

Nair, Suraj. "Acoustic Characterization of Flame Blowout Phenomenon." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10413.

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Combustor blowout is a very serious concern in modern land-based and aircraft engine combustors. The ability to sense blowout precursors can provide significant payoffs in engine reliability and life. The objective of this work is to characterize the blowout phenomenon and develop a sensing methodology which can detect and assess the proximity of a combustor to blowout by monitoring its acoustic signature, thus providing early warning before the actual blowout of the combustor. The first part of the work examines the blowout phenomenon in a piloted jet burner. As blowout was approached, the fl

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3

Ichihashi, Fumitaka. "Investigation of Combustion Instability in a Single Annular Combustor." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1299617901.

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4

Magri, Luca. "Adjoint methods in thermo-acoustic and combustion instability." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709417.

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5

Ibrahim, Zuhair M. A. "An acoustic energy framework for predicting combustion-driven acoustic instabilities in premixed gas-turbines." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3257392.

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Thesis (Ph. D.)--University of California, San Diego, 2007.<br>Title from first page of PDF file (viewed May 17, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 105-109).

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6

Austarheim, Nikolai. "DNS of acoustic Instabilities in low Emission Combustion Systems." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22356.

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In a state of the art gas turbine using Lean Pre-Mixed fuels one of the main challenges is efficient and reliable control of sound generated during combustion. Knowledge of sound generation in gas turbine combustion chambers has to be enhanced in order to develop a reliable model with predictive capabilites.In this thesis Direct Numerical Simulations of two dimensional laminar imploding circular flame fronts have been performed. One dimensional simulations of laminar opposing flame fronts have been performed to establish modeling conditions for the two dimensional simulations, evaluate the bou

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7

Dalamagas, B. C. "A non-linear acoustic source mechanism in gaseous combustion." Thesis, London South Bank University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355123.

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8

Lee, Doh-Hyoung. "Premixed flame kinematics in a longitudinal acoustic field." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/12134.

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9

Karkow, Douglas W. "Combustion instabilities: an experimental investigation on the effects of hydrogen in a lean premixed combustor." Thesis, University of Iowa, 2012. https://ir.uiowa.edu/etd/2911.

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10

Botura, César Augusto. "Desenvolvimento de um sistema de incineração de resíduos sólidos para utilização com combustão pulsante /." Guaratinguetá : [s.n.], 2005. http://hdl.handle.net/11449/106449.

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Resumo: Este trabalho tem a finalidade de investigar a incineração de resíduos sólidos na presença de ondas acústicas para incrementar o processo de combustão. Para tanto foi projetado e construído um forno rotativo para incineração de resíduo sólido industrial. Um combustor do tipo sintonizável foi desenvolvido e acoplado ao forno rotativo para indução de oscilações acústicas, além de outros acessórios utilizados no processo de combustão (alimentador de resíduos, ejetor, sonda para análise de gases). Os resultados obtidos mostram que a presença do campo acústico melhora o processo de combustã

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11

O'Connor, Jacqueline. "Response of a swirl-stabilized flame to transverse acoustic excitation." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43756.

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This work addresses the issue of transverse combustion instabilities in annular gas turbine combustor geometries. While modern low-emissions combustion strategies have made great strides in reducing the production of toxic emissions in aircraft engines and power generation gas turbines, combustion instability remains one of the foremost technical challenges in the development of next generation combustor technology. To that end, this work investigates the response of a swirling flow and swirl-stabilized flame to a transverse acoustic field is using a variety of high-speed laser techniques, e

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12

Davis, James Arthur. "Acoustic-vortical-combustion interaction in a solid fuel ramjet simulator." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/12947.

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13

Dutko, Alexander C. "Acoustic enhancement of water spray evaporation within a pulse combustor." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/17872.

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14

Mohan, Sripathi. "Acoustic radiation from premixed flames disturbed by turbulent velocity fluctuations." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/7938.

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15

Alves, Marcel Martins. "Employment of acoustic field for pollutant emission reduction under lean combustion." Instituto Tecnológico de Aeronáutica, 2011. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1930.

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Pulsating combustion is a technique that directly intervenes in combustion processes modifying pollutant emissions and increasing thermal efficiency by varying pressure and temperature in the flame region. The pulsations accelerate mixture rate between oxidant and fuel, resulting in a more intense combustion process, with low fuel waste and potential for low emission of pollutants originated by partial combustion, such as carbon monoxide, unburned hydrocarbons, and soot. The flame structure is modified by introducing an acoustic field in the process, and the flame has its color changed from ye

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16

Douasbin, Quentin. "Acoustic waves in combustion devices : interactions with flames and boundary conditions." Phd thesis, Toulouse, INPT, 2018. http://oatao.univ-toulouse.fr/20204/7/douasbin_quentin.pdf.

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Combustion devices are prone to combustion instabilities. They arise from a constructive coupling between the unsteady heat release rate of the flame and the resonant acoustic modes of the entire system. The occurence of such instabilities can pose a threat to both performance and integrity of combustion systems. Although these phenomena have been known for more than a century, avoiding their appearance in industrial engines is still challenging. The objective of this thesis is threefold: (1) study the dynamics of the resonant acoustic modes, (2) investigate the flame response of a liquid rock

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17

Cuquel, Alexis. "Dynamics and nonlinear thermo-acoustic stability analysis of premixed conical flames." Phd thesis, Ecole Centrale Paris, 2013. http://tel.archives-ouvertes.fr/tel-01000271.

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Thermo-acoustic instabilities in combustion chambers are generated by the interactions between a flame and the combustor acoustics, leading to a resonant coupling. These self-sustained oscillations may be observed in many practical systems such as domestic boilers, industrial furnaces, gas turbines or rocket engines. Although this phenomenon has already been the topic of many investigations, there is yet no generalized robust framework to predict the onset of these self-sustained oscillations and to determine the evolution of the flow variables within the combustor during unstable operation. T

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18

Chen, Tzengyuan. "Driving of axial acoustic fields by sidewall stabilized diffusion flames." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/12969.

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19

Mohan, Sripathi. "Acoustic radiation from premixed flames disturbed by turbulent velocity fluctuations." Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-06072004-131254/unrestricted/mohan%5Fsripathi%5F200405%5Fms.pdf.

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20

Blimbaum, Jordan Matthew. "Finite element analysis of acoustic wave transverse to longitudinal coupling during transverse combustion instability." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44757.

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Velocity-coupled combustion instability is a major issue facing lean combustor design in modern gas turbine applications. In this study, we analyze the complex acoustic field excited by a transverse acoustic mode in an annular combustor. This work is motivated by the need to understand the various velocity disturbance mechanisms present in the flame region during a transverse instability event. Recent simulation and experimental studies have shown that much of the flame response during these transverse instabilities may be due to the longitudinal motion induced by the fluctuating pressure fiel

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21

Macquisten, M. A. "The pulsed electric discharge as an acoustic probe for combustion chamber diagnostics." Thesis, London South Bank University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373899.

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22

Junior, Avandelino Santana. "Investigation of passive control devices to suppress acoustic instability in combustion chambers." Instituto Tecnológico de Aeronáutica, 2008. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=590.

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Combustion instability problems have been experienced during nearly every rocket engine development program, characterized by chamber pressure oscillations and high density of energy release in a volume having relatively low losses. Several distinct types of instability and their physical manifestations have been observed, although the frequency and amplitude of these oscillations and their external manifestations normally vary with the type of instability. The most destructive type of instability is referred to as high frequency instability, resonant combustion or acoustic instability, which

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23

Ni, Franchine. "Accounting for complex flow-acoustic interactions in a 3D thermo-acoustic Helmholtz solver." Phd thesis, Toulouse, INPT, 2017. http://oatao.univ-toulouse.fr/17930/7/NI_Franchine.pdf.

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Environmental concerns have motivated turbine engine manufacturers to create new combustor designs with reduced fuel consumption and pollutant emissions. These designs are however more sensitive to a mechanism known as combustion instabilities, a coupling between flame and acoustics that can generate dangerous levels of heat release and pressure fluctuations. Combustion instabilities can be predicted at an attractive cost by Helmholtz solvers. These solvers describe the acoustic behavior of an inviscid fluid at rest with a thermoacoustic Helmholtz equation, that can be solved in the frequency

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24

Hemchandra, Santosh. "Dynamics of turbulent premixed flames in acoustic fields." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29615.

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Thesis (Ph.D)--Aerospace Engineering, Georgia Institute of Technology, 2009.<br>Committee Chair: Lieuwen, Tim; Committee Member: Menon, Suresh; Committee Member: Peters, Norbert; Committee Member: Yang, Vigor; Committee Member: Zinn, Benjamin. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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25

Knadler, Michael. "Validation of a Physics-Based Low-Order Thermo-Acoustic Model of a Liquid-Fueled Gas Turbine Combustor and its Application for Predicting Combustion Driven Oscillations." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511861629413018.

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26

Emadi, Majid. "Flame structure and thermo-acoustic coupling for the low swirl burner for elevated pressure and syngas conditions." Diss., University of Iowa, 2012. https://ir.uiowa.edu/etd/4968.

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Reduction of the pollutant emissions is a challenge for the gas turbine industry. A solution to this problem is to employ the low swirl burner which can operate at lower equivalence ratios than a conventional swirl burner. However, flames in the lean regime of combustion are susceptible to flow perturbations and combustion instability. Combustion instability is the coupling between unsteady heat release and combustor acoustic modes where one amplifies the other in a feedback loop. The other method for significantly reducing NOx and CO2 is increasing fuel reactivity, typically done through the

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27

Martin, Christopher Reed. "Reduced-Order Models for the Prediction of Unsteady Heat Release in Acoustically Forced Combustion." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/30238.

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This work presents novel formulations for models describing acoustically forced combustion in three disjoint regimes; highly turbulent, laminar, and the moderately turbulent flamelet regime. Particular emphasis is placed on simplification of the models to facilitate analytical solutions while still reflecting real phenomenology. Each derivation is treated by beginning with general reacting flow equations, identifying a small subset of physics thought to be dominant in the corresponding regime, and making appropriate simplifications. Each model is non-dimensionalized and both naturally occur

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28

Bellows, Benjamin Davis. "Characterization of nonlinear heat release-acoustic interactions in gas turbine combustors." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-03262006-205604/.

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Thesis (Ph. D.)--Aerospace Engineering, Georgia Institute of Technology, 2006.<br>Dr. Jeffrey Cohen, Committee Member ; Dr. Jerry Seitzman, Committee Member ; Dr. Jeff Jagoda, Committee Member ; Dr. Ben Zinn, Committee Member ; Dr. Tim Lieuwen, Committee Chair.

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29

Wright, Andrew D. "Acoustic boundary condition estimation in a near-scale gas-turbine combustor." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-08222008-063430/.

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30

Abdou, Wael Saber Soliman. "Identification of acoustic emission sources in machinery : application to injection/combustion processes in diesel engines." Thesis, Heriot-Watt University, 2015. http://hdl.handle.net/10399/2979.

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The high temporal resolution of Acoustic Emission offers great promise in the on-line monitoring of complex machines such as diesel engines. The fuel injection process is one of the most important processes in the diesel engine and its timing and fuel delivery control are critical in combustion efficiency. In this work, the phenomena leading to the generation of acoustic emission during injection are investigated by simulation of the injection process in a specially designed rig and through test in running engines on a test-bed. Signal processing approaches are devised to produce diagnostic in

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31

Caceres, Marcos. "Impact of transverse acoustic modes on a linearly arranged two-phase flow swirling flames." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMIR01/document.

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Les besoins énergétiques de la population mondiale ne cessent d’augmenter. Les prévisions indiquent par exemple une forte croissance de la demande du secteur du transport aéronautique. La recherche de systèmes toujours plus performants et moins polluants est nécessaire. Des nouveaux concepts pour la combustion ont été mis au point et appliqués aux turbines à gaz. Parmi eux il existe ceux basés sur la combustion en prémélange pauvre ou en prémélange pauvre pré-vaporisé dans le cas où le carburant utilisé est liquide. Les nouveaux systèmes énergétiques basés sur la combustion en régime pauvre so

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32

Massey, Jeffery A. "Indication of cylinder pressure rise rate by means of vibration and acoustic emissions of an internal combustion engine." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2008. http://scholarsmine.mst.edu/thesis/pdf/Massey_09007dcc804cc3c8.pdf.

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Thesis (M.S.)--Missouri University of Science and Technology, 2008.<br>Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed April 1, 2008) Includes bibliographical references (p. 127-128).

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Tran, Nicolas. "Influence de la condition limite acoustique amont sur les instabilités de combustion de grande amplitude : conception d’un système robuste de contrôle d’impédance." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2009. http://www.theses.fr/2009ECAP0013/document.

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Les contraintes économiques, environnementales et sociétales de ces vingt dernières années notamment dans les domaines de l’énergie et des transports ont débouché sur le développement de nouvelles technologies faisant intervenir la combustion pauvre et prémélangée. Ce mode de combustion à partir d'un mélange homogène conduit à des températures de flamme plus faibles qui permettent de réduire les émissions d'oxydes d'azote tout en limitant la production d'oxydes de carbone. Pour autant, la combustion pauvre prémélangée présente le désavantage d’être sensible à toute forme de couplage notamment

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Narra, Venkateswarlu. "High Frequency Acoustic Wave Scattering From Turbulent Premixed Flames." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22689.

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This thesis describes an experimental investigation of high frequency acoustic wave scattering from turbulent premixed flames. The objective of this work was to characterize the scattered incoherent acoustic field and determine its parametric dependence on frequency, flame brush thickness, incident and measurement angles, mean velocity and flame speed. The experimental facility consists of a slot burner with a flat flame sheet that is approximately 15 cm wide and 12 cm tall. The baseline cold flow characteristics and flame sheet statistics were extensively characterized. Studies were performed

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35

Silva, Camilo F. "Numerical study of combustion noise in gas turbines." Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20240/document.

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La recherche en bruit de combustion est de nos jours majoritairement consacrée au développement d'outils de calcul du bruit rayonné par les flammes. Les méthodes actuelles de CFD telles que la LES ou la DNS sont capables de fournir le champ acoustique rayonné par des sources de bruit, mais elles sont cependant limitées à des domaines de faible taille, ceci dû à leur fort coût de calcul. Pour surmonter cette limitation, on a vu l'émergence de méthodes hybrides. Dans cette approche, les sources de bruit sont découplées du son rayonné. Les sources sont alors calculées par les méthodes de DNS et d

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36

Trouvé, Arnaud. "Instabilités hydrodynamiques et instabilités de combustion de flammes turbulentes prémélangées." Châtenay-Malabry, Ecole centrale de Paris, 1989. http://www.theses.fr/1989ECAP0097.

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Etude des modes de combustion instable observes sur une maquette de statoréacteur ou l'instabilité est le résultat d'interactions complexes entre la dynamique de l'écoulement dans la zone de réaction, les processus de dégagement de chaleur et le comportement acoustique du système confine. Etude des modes hydrodynamiques au cours d'un régime de combustion stable

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37

Méry, Yoann. "Mécanismes d'instabilités de combustion haute-fréquence et application aux moteurs-fusées." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2010. http://www.theses.fr/2010ECAP0012.

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Cette thèse présente une étude des instabilités haute-fréquence dans les moteurs-fusées. Ce phénomène, qui a posé de nombreux problèmes dans les programmes de développement de moteur, est abordé de trois façons complémentaires : expérimentalement, théoriquement et numériquement. Premièrement, des expériences sont menées afin d’identifier les principaux processus et d’apporter les mécanismes ayant lieu lorsque le moteur devient instable. Pour parvenir à ce stade, un nouveau modulateur (VHAM), capable de créer des ondes acoustiques représentatives de ce qui se produit dans un moteur réel, est co

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Cavaglieri, Marcelo Renato 1975. "Estudo experimental do fenômeno de onda em coletores de admissão para motores de combustão interna : Experimental study of the wave phenomena into the intake manifolds for internal combustion engines." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265919.

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Orientador: Rogério Gonçalves dos Santos<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica<br>Made available in DSpace on 2018-08-24T21:02:17Z (GMT). No. of bitstreams: 1 Cavaglieri_MarceloRenato_M.pdf: 17998120 bytes, checksum: 987df39d379a639bae4123aeab57a9d6 (MD5) Previous issue date: 2014<br>Resumo: Com o intuito de otimizar o Motor de Combustão Interna e encontrar aplicações que o utilizem de forma racional e eficiente, nessa dissertação estuda-se o comportamento dinâmico da pressão na cavidade dos Coletores de admissão, já que o escoamento

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Idahosa, Uyi. "COMBUSTION DYNAMICS AND FLUID MECHANICS IN ACOUSTICALLY PERTURBED NON-PREMIXED SWIRL-STABILIZED FLAMES." Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2721.

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The prevalence of gas turbines operating in primarily lean premixed modes is predicated on the need for lower emissions and increased efficiency. An enhancement in the mixing process through the introduction of swirl in the combustion reactants is also necessary for flame stabilization. The resulting lean swirling flames are often characterized by a susceptibility to feedback between velocity, pressure and heat release perturbations with a potential for unstable self-amplifying dynamics. The existing literature on combustion dynamics is predominantly dedicated to premixed flame configurations

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Hernández, Vera Ignacio. "Soot modelling in flames and Large-Eddy Simulation of thermo-acoustic instabilities." Thesis, Toulouse, INPT, 2011. http://www.theses.fr/2011INPT0134/document.

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Dans la première partie de cette thèse de doctorat une méthodologie est présentée qui permet de prédire les niveaux de suies produits dans des flammes laminaires monodimensionnelles, ou un modèle semi-empirique de suies est utilisé en combinaison avec une chimie complexe et un solveur radiatif détaillé. La méthodologie est appliquée au calcul de suies dans une série de flammes de diffusion à contre-courant d'éthylène/air. Plusieurs modèles d'oxydation de suies sont testés et les constantes du modèle sont ajustées afin de retrouver un meilleur accord avec les expériences. L'effet des pertes the

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Farina, Jordan T. "Application of Multi-Port Mixing for Passive Suppression of Thermo-Acoustic Instabilities in Premixed Combustors." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/50533.

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The utilization of lean premixed combustors has become attractive to designers of industrial gas turbines as a means of meeting strict emissions standards without compromising efficiency. Mixing the fuel and air prior to combustion allows for lower temperature flame zones, creating the potential for drastically reduced nitrous oxide emissions. While effective, these systems are commonly plagued by combustion driven instabilities. These instabilities produce large pressure and heat release rate fluctuations due to a resonant interaction between the combustor acoustics and the flame. A prima

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Zhou, Limin. "ASSESSING AND MITIGATING AIRBORNE NOISE FROM POWER GENERATION EQUIPMENT." UKnowledge, 2013. http://uknowledge.uky.edu/me_etds/22.

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This dissertation examines the assessment and mitigation of airborne noise from power generation equipment. The first half of the dissertation investigates the diagnosis and treatment of combustion oscillations in boilers. Sound is produced by the flame and is reflected downstream from the combustion chamber. The reflected sound waves perturb the mixture flow or equivalence ratio increasing the heat release pulsations and the accompanying sound produced by the flame. A feedback loop model for determining the likelihood of and diagnosing combustion oscillations was reviewed, enhanced, and then

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Motheau, Emmanuel. "Accounting for mean flow effects in a zero-Mach number thermo-acoustic solver : application to entropy induced combustion instabilities." Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2013. http://tel.archives-ouvertes.fr/tel-00983655.

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Pratiquement toutes les chambres de combustion présentent des instabilités. Par conséquent, il est nécessaire de mieux les comprendre afin de les contrôler. Une possibilité est de simuler l'écoulement réactif à l'intérieur d'une chambre de combustion grâce à la Simulation aux Grandes Echelles (SGE). Cependant la SGE est très coûteuse en terme de capacité de calcul. Une autre possibilité est de réduire la complexité du problème à une simple équation d'onde thermoacoustique (équation dite de Helmholtz), qui peut être résolue en fréquence comme un problème aux valeurs propres. Le couplage entre l

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Howard, Randall E. "Acoustical behavior of a turbulent, ducted, premixed, hydrogen- flame burner." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/91121.

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The acoustic source structure, acoustic farfield, and duct terminating impedances fully describe the acoustics of a source within a duct. A main goal in the study of noise generated by turbulent combustion is to characterize the structure of the flame as an acoustic source. Data describing the farfield and duct terminating conditions allow for the testing of combustion noise models. The acoustic farfield of a premixed flame burner is documented for various power levels and air-to-fuel ratios. The terminating impedance of the burner exhaust is determined by a method using the transfer functio

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Gunasekaran, Barani. "Development and validation of a pressure based CFD methodology for acoustic wave propagation and damping." Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/8740.

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Combustion instabilities (thermo-acoustic pressure oscillations) have been recognised for some time as a problem limiting the development of low emissions (e.g., lean burn) gas turbine combustion systems, particularly for aviation propulsion applications. Recently, significant research efforts have been focused on acoustic damping for suppression of combustion instability. Most of this work has either been experimental or based on linear acoustic theory. The last 3-5 years has seen application of density based CFD methods to this problem, but no attempts to use pressure-based CFD methods which

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Crawford, Jackie H. III. "Factors that limit control effectiveness in self-excited noise driven combustors." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43647.

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A full Strouhal number thermo-acoustic model is purposed for the feedback control of self excited noise driven combustors. The inclusion of time delays in the volumetric heat release perturbation models create unique behavioral characteristics which are not properly reproduced within current low Strouhal number thermo acoustic models. New analysis tools using probability density functions are introduced which enable exact expressions for the statistics of a time delayed system. Additionally, preexisting tools from applied mathematics and control theory for spectral analysis of time delay sy

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Merlin, Cindy. "Simulation numérique de la combustion turbulente : Méthode de frontières immergées pour les écoulements compressibles, application à la combustion en aval d’une cavité." Thesis, Rouen, INSA, 2011. http://www.theses.fr/2011ISAM0020/document.

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Une méthode de frontières immergées est développée pour la simulation d’écoulements compressibles et validée au travers de cas-tests spécifiques (réflexion d’ondes acoustiques et quantification de la conservation de la masse dans des canaux inclinés). La simulation aux grandes échelles (LES) d’une cavité transsonique est ensuite présentée. Le bouclage aéro-acoustique, très sensible aux conditions aux limites, est reproduit avec précision par la LES dans le cas où les parois sont immergées dans un maillage structurée. La comparaison des stratégies de modélisation de sous-maille pour cet écoulem

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Lagimoniere, Ernest Eugene Jr. "The Design and Construction of a High Bandwidth Proportional Fuel Injection System for Liquid Fuel Active Combustion Control." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34693.

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This last decade experienced a sudden increase of interest in the control of thermo-acoustic instabilities, in particular through the use of fuel modulation techniques. The primary goal of this research was to design, construct and characterize a high bandwidth proportional fuel injection system, which could be used to study the effect of specific levels of fuel modulation on the combustion process and the reduction of thermo-acoustic instabilities. A fuel injection system, incorporating the use of a closed loop piston and check valve, was designed to modulate the primary fuel supply of an

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Reichling, Gilles [Verfasser], and Manfred [Akademischer Betreuer] Aigner. "Development of numerical methods for the calculation of thermo-acoustic interactions in gas turbine combustion chambers / Gilles Reichling. Betreuer: Manfred Aigner." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2015. http://d-nb.info/1072073056/34.

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Sánchez, Orgaz Eva María. "Advanced numerical techniques for the acoustic modelling of materials and noise control devices in the exhaust system of internal combustion engines." Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/64090.

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[EN] This Thesis is focused on the development and implementation of efficient numerical methods for the acoustic modelling and design of noise control devices in the exhaust system of combustion engines. Special attention is paid to automotive perforated dissipative silencers, in which significant differences are likely to appear in their acoustic behaviour, depending on the temperature variations within the absorbent material. Also, material heterogeneities can alter the silencer attenuation performance. Therefore, numerical techniques considering all these features are required to guarantee

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