Relevant bibliographies by topics / Combustion; Flame dynamics

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
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Academic literature on the topic 'Combustion; Flame dynamics'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Combustion; Flame dynamics"

1

Ju, Yiguang, Kaoru Maruta, and Takashi Niioka. "Combustion Limits." Applied Mechanics Reviews 54, no. 3 (May 1, 2001): 257–77. http://dx.doi.org/10.1115/1.3097297.

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Combustion limits and related flame behaviors are reviewed, especially with regard to fundamental problems. As for premixed flames, after a brief historical overview of research on the flammability limit, recent trends of research on planar propagating flames, curved propagating flames, flame balls, and stretched premixed flames are discussed, and then all types of flames are summarized. Finally, instability and dynamics near limits is discussed. With regard to combustion limits of counterflow diffusion flames and droplet flames, their instability is demonstrated, then an explanation of lifted flames and edge flames is presented. Suggestions for future work are also discussed in the concluding remarks. There are 166 references cited in this review article.
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Innocenti, Alessandro, Antonio Andreini, Bruno Facchini, and Antonio Peschiulli. "Numerical analysis of the dynamic flame response of a spray flame for aero-engine applications." International Journal of Spray and Combustion Dynamics 9, no. 4 (May 16, 2017): 310–29. http://dx.doi.org/10.1177/1756827717703577.

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Incoming standards on NO x emissions are motivating many aero-engine manufacturers to adopt the lean burn combustion concept. One of the most critical issues affecting this kind of technology is the occurrence of thermo-acoustic instabilities that may compromise combustor life and integrity. Therefore the prediction of the thermo-acoustic behaviour of the system becomes of primary importance. In this paper, the complex interaction between the system acoustics and a turbulent spray flame for aero-engine applications is numerically studied. The dynamic flame response is computed exploiting reactive URANS simulations and system identification techniques. Great attention has been devoted to the impact of liquid fuel evolution and droplet dynamics. For this purpose, the GE Avio PERM (partially evaporating and rapid mixing) lean injection system has been analysed, focussing attention on the effect of several modelling parameters on the combustion and on the predicted flame response. A frequency analysis has also been set up and exploited to obtain even more insight on the dynamic flame response of the spray flame. The application is one of the few in the literature where the dynamic flame response of spray flames is numerically investigated, providing a description in terms of flame transfer function and detailed information on the physical phenomena.
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Barmina, I., R. Valdmanis, M. Zake, H. Kalis, M. Marinaki, and U. Strautins. "Magnetic Field Control of Combustion Dynamics." Latvian Journal of Physics and Technical Sciences 53, no. 4 (August 1, 2016): 36–47. http://dx.doi.org/10.1515/lpts-2016-0027.

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AbstractExperimental studies and mathematical modelling of the effects of magnetic field on combustion dynamics at thermo-chemical conversion of biomass are carried out with the aim of providing control of the processes developing in the reaction zone of swirling flame. The joint research of the magnetic field effect on the combustion dynamics includes the estimation of this effect on the formation of the swirling flame dynamics, flame temperature and composition, providing analysis of the magnetic field effects on the flame characteristics. The results of experiments have shown that the magnetic field exerts the influence on the flow velocity components by enhancing a swirl motion in the flame reaction zone with swirl-enhanced mixing of the axial flow of volatiles with cold air swirl, by cooling the flame reaction zone and by limiting the thermo-chemical conversion of volatiles. Mathematical modelling of magnetic field effect on the formation of the flame dynamics confirms that the electromagnetic force, which is induced by the electric current surrounding the flame, leads to field-enhanced increase of flow vorticity by enhancing mixing of the reactants. The magnetic field effect on the flame temperature and rate of reactions leads to conclusion that field-enhanced increase of the flow vorticity results in flame cooling by limiting the chemical conversion of the reactants.
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Palies, Paul, Milos Ilak, and Robert Cheng. "Transient and limit cycle combustion dynamics analysis of turbulent premixed swirling flames." Journal of Fluid Mechanics 830 (October 5, 2017): 681–707. http://dx.doi.org/10.1017/jfm.2017.575.

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Premixed low swirling flames (methane–air and hydrogen–methane–air) are experimentally investigated for three different regimes. Stable, local transient to instability and limit cycle regimes corresponding to three distinct equivalence ratios are considered. Dynamic mode decomposition is applied to the hydrogen–air–methane flame to retrieve the modes frequencies, growth rates and spatial distributions for each regime. The results indicate that a vortical wave propagating along the flame front is associated with the transition from stability to instability. In addition, it is shown that a key effect on stability is the location of the non-oscillating (0 Hz) flame component. The phase-averaged unsteady motion of the flames over one cycle of oscillation shows the vortical wave rolling up the flame front. The Rayleigh index maps are formed to identify the region of driving and damping of the self-sustained oscillation, while the flame transfer function phase leads to the propagation mode of the perturbations along the flame front. The second mechanism identified concerns the swirl number fluctuation induced by the mode conversion. By utilizing hypotheses for the flow field and the flame structure, it is pointed out that those mechanisms are at work for both flames (methane–air and hydrogen–methane–air) and their effects on the unsteady heat release are determined. Both unsteady heat release contributions, the vortical wave induces flame surface fluctuations and swirl number oscillation induces unsteady turbulent burning velocity, are in phase opposition and of similar amplitudes.
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Yakovenko, Ivan, Alexey Kiverin, and Ksenia Melnikova. "Ultra-Lean Gaseous Flames in Terrestrial Gravity Conditions." Fluids 6, no. 1 (January 3, 2021): 21. http://dx.doi.org/10.3390/fluids6010021.

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Development of the combustion process in the gaseous mixtures of near-limit composition is of great interest for fundamental aspects of combustion theory and fire-safety applications. The dynamics of ultra-lean gaseous flames in near-limit mixtures is governed by many effects, such as buoyancy, preferential diffusion, radiation, and instability development. Though ultra-lean combustion was extensively studied in microgravity conditions, the influence of gravity on the ultra-lean flame structure and stability is still poorly understood. The paper is devoted to deepening the knowledge of ultra-lean flame dynamics in hydrogen-air mixtures under terrestrial gravity conditions. The spatial structures of the flame developing under the effect of buoyancy forces are investigated employing detailed numerical analysis. Different modes of near-limit flame evolution are observed depending on the mixture concentration. In particular, we registered and described three distinct spatial structures: individual kernels tending to extinguish in leanest compounds, complex multi-kernel structures in marginal compositions, and stable cap-shaped flames in more chemically active mixtures. We apply the flame-bubble analogy to interpret flame dynamics. On this basis, the diagram in the Re-Fr plane is developed. That allows classifying the emerging flame structures and determine flame stability. Additionally, different ignition modes are studied, and the mechanisms determining the impact of ignition mode on the flammability limits are distinguished. Obtained results provide useful insights into the processes of flame quenching and development in near-limit hydrogen-air mixtures under real gravity conditions and can be applied in the design of contemporary fire-safety systems.
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Ravikrishna, RV, and AB Sahu. "Advances in understanding combustion phenomena using non-premixed and partially premixed counterflow flames: A review." International Journal of Spray and Combustion Dynamics 10, no. 1 (November 14, 2017): 38–71. http://dx.doi.org/10.1177/1756827717738168.

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Counterflow flames provide an ideal platform for understanding the flame structure and as a model to study the effect of physical and chemical perturbations on the flame structure. This article reviews the advances made in the understanding of combustion dynamics and chemistry through experimental and numerical studies in counterflow non-premixed and partially premixed flames. Key contributions on fundamental aspects such as extinction, ignition and effect of perturbations on the stability of diffusion flames are first summarized and analysed. The review then focuses on the progress made in the understanding of the effect of inert particles and flame suppressants on the flame characteristics. A review of detailed studies on edge flames facilitates further understanding of local quenching and re-ignition phenomena in highly turbulent flames. The influence of radiation model and unsteady flow-conditions on the flame kinetics and dynamics along with work on NOx kinetics has been discussed. The review also outlines that specific experiments need to be carried out over a wide range of conditions for further understanding and validation of numerical models.
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Chorpening, B. T., J. D. Thornton, E. D. Huckaby, and K. J. Benson. "Combustion Oscillation Monitoring Using Flame Ionization in a Turbulent Premixed Combustor." Journal of Engineering for Gas Turbines and Power 129, no. 2 (August 30, 2006): 352–57. http://dx.doi.org/10.1115/1.2431390.

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To achieve very low NOx emission levels, lean-premixed gas turbine combustors have been commercially implemented that operate near the fuel-lean flame extinction limit. Near the lean limit, however, flashback, lean blow off, and combustion dynamics have appeared as problems during operation. To help address these operational problems, a combustion control and diagnostics sensor (CCADS) for gas turbine combustors is being developed. CCADS uses the electrical properties of the flame to detect key events and monitor critical operating parameters within the combustor. Previous development efforts have shown the capability of CCADS to monitor flashback and equivalence ratio. Recent work has focused on detecting and measuring combustion instabilities. A highly instrumented atmospheric combustor has been used to measure the pressure oscillations in the combustor, the OH emission, and the flame ion field at the premix injector outlet and along the walls of the combustor. This instrumentation allows examination of the downstream extent of the combustion field using both the OH emission and the corresponding electron and ion distribution near the walls of the combustor. In most cases, the strongest pressure oscillation dominates the frequency behavior of the OH emission and the flame ion signals. Using this highly instrumented combustor, tests were run over a matrix of equivalence ratios from 0.6 to 0.8, with an inlet reference velocity of 25m∕s(82ft∕s). The acoustics of the fuel system for the combustor were tuned using an active-passive technique with an adjustable quarter-wave resonator. Although several statistics were investigated for correlation with the dynamic pressure in the combustor, the best correlation was found with the standard deviation of the guard current. The data show a monotonic relationship between the standard deviation of the guard current (the current through the flame at the premix injector outlet) and the standard deviation of the chamber pressure. Therefore, the relationship between the standard deviation of the guard current and the standard deviation of the pressure is the most promising for monitoring the dynamic pressure of the combustor using the flame ionization signal. This addition to the capabilities of CCADS would allow for dynamic pressure monitoring on commercial gas turbines without a pressure transducer.
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Gutmark, E., T. P. Parr, D. M. Parr, and K. C. Schadow. "Planar Imaging of Vortex Dynamics in Flames." Journal of Heat Transfer 111, no. 1 (February 1, 1989): 148–55. http://dx.doi.org/10.1115/1.3250637.

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The interaction between the fluid dynamics and the combustion process in an annular diffusion flame was studied experimentally using the Planar Laser Induced Fluorescence (PLIF) technique. The local temperature and OH radical fluorescence signals were mapped in the entire flame cross section. The flame was forced at different instability frequencies, thus enabling the study of the evolution and interaction of large-scale structures in the flame shear layer. The present study of the effect of fluid dynamics on combustion is part of a more comprehensive program aimed at understanding and controlling the effect of heat release, density variations, and reaction parameters on the shear layer evolution.
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Murugesan, Meenatchidevi, Balasubramanian Singaravelu, Abhijit K. Kushwaha, and Sathesh Mariappan. "Onset of flame-intrinsic thermoacoustic instabilities in partially premixed turbulent combustors." International Journal of Spray and Combustion Dynamics 10, no. 3 (February 21, 2018): 171–84. http://dx.doi.org/10.1177/1756827718758511.

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We investigate the onset of thermoacoustic instabilities in a turbulent combustor terminated with an area contraction. Flow speed is varied in a swirl-stabilized, partially premixed combustor and the system is observed to undergo a dynamical transition from combustion noise to instability via intermittency. We find that the frequency of thermoacoustic oscillations does not lock-on to any of the acoustic modes. Instead, we observe that the dominant mode in the dynamics of combustion noise, intermittency and thermoacoustic instability is a function of the flow speed. We also find that the observed mode is insensitive to the changes in acoustic field of the combustor, but it varies as a function of upstream flow time scale. This new kind of thermoacoustic instability was independently discovered in the recent theoretical analysis of premixed flames. They are known as intrinsic thermoacoustic modes. In this paper, we report the experimental observation and the route to flame intrinsic thermoacoustic instabilities in partially premixed flame combustors. A simplified low-order network model analysis is performed to examine the driving mechanism. Frequencies predicted by the network model analysis match well with the experimentally observed dominant frequencies. Intrinsic flame-acoustic coupling between the unsteady heat release rate and equivalence ratio fluctuations occurring at the location of fuel injection is found to play a key role. Further, we observe intrinsic thermoacoustic modes to occur only when the acoustic reflection co-efficients at the exit are low. This result indicates that thermoacoustic systems with increased acoustic losses at the boundaries have to consider the possibility of flame intrinsic thermoacoustic oscillations.
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Pun, W., S. L. Palm, and F. E. C. Culick. "Combustion dynamics of an acoustically forced flame." Combustion Science and Technology 175, no. 3 (March 2003): 499–521. http://dx.doi.org/10.1080/00102200302384.

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Dissertations / Theses on the topic "Combustion; Flame dynamics"

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Altay, Hurrem Murat. "Vortex driven flame dynamics and combustion instability." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32379.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
Includes bibliographical references (leaves 87-93).
Combustion instability in premixed combustors mostly arises due to the coupling between heat release rate dynamics and system acoustics. It is crucial to understand the instability mechanisms to design reliable, high efficiency, low emission gas turbine combustors. In this thesis, elementary processes acting as a source of unsteady heat release rate are described. These elementary processes are acoustic wave-flame interactions, flame-vortex interactions, equivalence ratio fluctuations, flame-wall interactions and the unsteady stretch rate. To investigate the flame- vortex interaction mechanism, a parametric study is performed in single and double expansion dump combustors. 2-D simulations are performed using the random vortex method combined with thin flame model of premixed combustion. The inlet velocity of the combustor is forced sinusoidally at various amplitudes and frequencies, and the heat release rate response is evaluated. It is shown that the heat release rate dynamics are governed by the cyclical formation of a large wake vortex and its interaction with the flame. Maximum heat release rate in a cycle is reached a short time after the breakup of the vortex, which causes rapid burning of the reactants trapped within the structure. The geometry and operating conditions of the combustor control the mechanism by which the vortex breakup is initiated. For short cavities, the impingement of the large wake vortex onto the forward facing step is responsible from the vortex breakup.
(cont.) On the other hand, in long cavities, the vortex breakup is initiated as the wake vortex impinges on the upper cavity wall in single expansion dump combustor, or the vortex forming in the other half of the combustor in double expansion dump combustor. Furthermore, the effect of the air injection in the cross stream direction close to the dump plane on equivalence ratio is investigated. It is shown experimentally that high amplitude pressure oscillation in the combustor during unstable operation causes fluctuation in the injected jet velocity. The oscillatory jet velocity affects the incoming equivalence ratio depending on the momentum ratio of the jet to the primary stream. A critical momentum ratio is defined at which the amplitude of the equivalence ratio oscillations reaches a maximum.
by Hurrem Murat Altay.
S.M.
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Preetham, Preetham. "Modeling the Response of Premixed Flames to Flow Disturbances." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19817.

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Modeling the Response of Premixed Flames to Flow Disturbances Preetham 178 pages Directed by Dr. Tim Lieuwen Low emissions combustion systems for land based gas turbines rely on a premixed or partially premixed combustion process. These systems are exceptionally prone to combustion instabilities which are destructive to hardware and adversely affect performance and emissions. The success of dynamics prediction codes is critically dependent on the heat release model which couples the flame dynamics to the system acoustics. So the principal objective of the current research work is to predict the heat release response of premixed flames and to isolate the key non-dimensional parameters which characterize its linear and nonlinear dynamics. Explicit analytical solutions of the G- equation are derived in the linear and weakly nonlinear regime using the Small Perturbation Method (SPM). For the fully nonlinear case, the flame-flow interaction effects are captured by developing an unsteady, compressible, coupled Euler-G-equation solver with a Ghost Fluid Method (GFM) module for applying the jump conditions across the flame. The flame s nonlinear response is shown to exhibit two qualitatively different behaviors. Depending on the operating conditions and the disturbance field characteristics, it is shown that a combustor may exhibit supercritical bifurcations leading to a single stable limit cycle amplitude or exhibit sub-critical bifurcations wherein multiple stable solutions for the instability amplitude are possible. In addition, this study presents the first analytical model which captures the effects of unsteady flame stretch on the heat release response and thus extends the applicability of current models to high frequency instabilities, such as occurring during screech. It is shown that unsteady stretch effects, negligible at low frequencies (100 s of Hz) become significant at screeching frequencies (1000 s of Hz). Furthermore, the analysis also yields insight into the significant spatial dependence of the mean and perturbation velocity field induced by the coupling between the flame and the flow field. In order to meaningfully compare the heat release response across different flame configurations, this study has identified that the reference velocity (for defining the transfer function) should be based on the effective normal velocity perturbing the flame and the Strouhal number should be based on the effective residence time of the flame wrinkles.
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Plaks, Dmitriy Vital. "Dynamics of longitudinally forced bluff body flames with varying dilatation ratios." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31767.

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Thesis (M. S.)--Aerospace Engineering, Georgia Institute of Technology, 2010.
Committee Chair: Tim Lieuwen; Committee Member: Jeff Jagoda; Committee Member: Suresh Menon. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Shin, Dong-hyuk. "Premixed flame kinematics in a harmonically oscillating velocity field." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45950.

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Air pollution regulations have driven modern power generation systems to move from diffusion to premixed combustion. However, these premixed combustion systems are prone to combustion instability, causing high fluctuations in pressure and temperature. This results in shortening of component life, system failure, or even catastrophic disasters. A large number of studies have been performed to understand and quantify the onset of combustion instability and the limit cycle amplitude. However, much work remains due to the complexity of the process associated with flow dynamics and chemistry. This thesis focuses on identifying, quantifying and predicting mechanisms of flame response subject to disturbances. A promising tool for predicting combustion instability is a flame transfer function. The flame transfer function is obtained by integrating unsteady heat release over the combustor domain. Thus, the better understanding of spatio-temporal characteristics of flame is required to better predict the flame transfer function. The spatio-temporal flame response is analyzed by the flame kinematic equation, so called G-equation. The flame is assumed to be a thin interface separating products and reactant, and the interface is governed by the local flow and the flame propagation. Much of the efforts were done to the flame response subject to the harmonic velocity disturbance. A key assumption allowing for analytic solutions is that the velocity is prescribed. For the mathematical tools, small perturbation theory, Hopf-Lax formula and numerical simulation were used. Solutions indicated that the flame response can be divided into three regions, referred to here as the near-field, mid-field, and farfield. In each regime, analytical expressions were derived, and those results were compared with numerical and experimental data. In the near field, it was shown that the flame response grows linearly with the normal component of the velocity disturbance. In the mid field, the flame response shows peaks in gain, and the axial location of these peaks can be predicted by the interference pattern by two characteristic waves. Lastly, in the far field where the flame response decreases, three mechanisms are studied; they are kinematic restoration, flame stretch, and turbulent flow effects. For each mechanism, key parameters are identified and their relative significances are compared.
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Wheater, Guy. "Laser tomography of a buoyant turbulent diffusion flame." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358848.

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Petchenko, Arkady. "Numerical study of flame dynamics." Doctoral thesis, Umeå : Institute of Physics, Umeå Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1313.

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Ahmed, Mahbub. "Investigation on the flame dynamics of meso-combustors." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.

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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 flame detached from one side of the burner and showed increased flame tip fluctuations, resulting in an increase in low frequency acoustics. Work was then focused on swirling combustion systems. Close to blowout, localized extinction/re-ignition events were observed, which manifested as bursts in the acoustic signal. These events increased in number and duration as the combustor approached blowout, resulting an increase in low frequency acoustics. A variety of spectral, wavelet and thresholding based approaches were developed to detect precursors to blowout. The third part of the study focused on a bluff body burner. It characterized the underlying flame dynamics near blowout in greater detail and related it to the observed acoustic emissions. Vorticity was found to play a significant role in the flame dynamics. The flame passed through two distinct stages prior to blowout. The first was associated with momentary strain levels that exceed the flames extinction strain rate, leading to flame holes. The second was due to large scale alteration of the fluid dynamics in the bluff body wake, leading to violent flapping of the flame front and even larger straining of the flame. This led to low frequency acoustic oscillations, of the order of von Karman vortex shedding. This manifested as an abrupt increase in combustion noise spectra at 40-100 Hz very close to blowout. Finally, work was also done to improve the robustness of lean blowout detection by developing integration techniques that combined data from acoustic and optical sensors.
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Kaiser, Thomas. "Impact of Flow Rotation on Flame Dynamics and Hydrodynamic Stability." Thesis, Toulouse, INPT, 2019. http://oatao.univ-toulouse.fr/24115/1/Kaiser_Thomas.pdf.

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This thesis investigates large scale flow rotation in two configurations. In the first, the effect of flow rotation on a laminar flame is investigated. The flame is anchored in the wake of a cylindrical bluff body. The flow rotation is introduced by turning the cylinder along its axis. It is shown by Direct Numerical Simulation (DNS), that the cylinder rotation breaks the symmetry of both flame branches. Flame Transfer Function (FTF) measurements performed by the Wiener-Hopf Inversion suggest, that low rotation rates lead to deep gaps in the gain and the flame becomes almost insensitive to acoustic perturbation at a specific frequency. It furthermore is demonstrated that this decrease in gain of the FTF is due to destructive interference of the heat release signals caused by the two flame branches. The frequency at which the gain becomes almost zero can be adjusted by tuning the cylinder rotation rate. The study suggests that controlling the symmetry of the flame could be a tool of open-loop control of thermoacoustic instabilities.
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Thumuluru, Sai Kumar. "Effect of harmonic forcing on turbulent flame properties." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37099.

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Lean premixed combustors are highly susceptible to combustion instabilities, caused by the coupling between heat release fluctuations and combustor acoustics. In order to predict the conditions under which these instabilities occur and their limit cycle amplitudes, understanding of the amplitude dependent response of the flame to acoustic excitation is required. Extensive maps of the flame response were obtained as a function of perturbation amplitude, frequency, and flow velocity. These maps illustrated substantial nonlinearity in the perturbation velocity - heat release relationship, with complex topological dependencies that illustrate folds and kinks when plotted in frequency-amplitude-heat release space. A detailed analysis of phase locked OH PLIF images of acoustically excited swirl flames was used to identify the key controlling physical processes and qualitatively discuss their characteristics. The results illustrate that the flame response is not controlled by any single physical process but rather by several simultaneously occurring processes which are potentially competing, and whose relative significance depends upon forcing frequency, amplitude of excitation, and flame stabilization dynamics. An in-depth study on the effect of acoustic forcing on the turbulent flame properties was conducted in a turbulent Bunsen flame using PIV measurements. The results showed that the flame brush thickness and the local consumption speed were modulated in the presence of acoustic forcing. These results will not only be a useful input to help improve combustion dynamics predictions but will also help serve as validation data for models.
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Books on the topic "Combustion; Flame dynamics"

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International, Colloquium on Dynamics of Explosions and Reactive Systems (11th 1987 Warsaw Poland). Dynamics of reactive systems. Washington, DC: American Institute of Aeronautics and Astronautics, 1988.

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International Colloquium on Dynamics of Explosions and Reactive Systems (10th 1985 Berkeley, Calif.). Dynamics of reactive systems. New York, NY: American Institute of Aeronautics and Astronautics, 1986.

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NATO Advanced Research Workshop on "Mathematical Modeling in Combustion and Related Topics" (1987 Lyon, France). Mathematical modeling in combustion and related topics. Dordrecht: M. Nijhoff, 1988.

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Toner, S. J. Entrainment, chemistry and structures of fire plumes. Gaithersburg, MD: U.S. Dept. of Commerce, National Bureau of Standards, Center for Fire Research, 1987.

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L, Kuhl A., and American Institute of Aeronautics and Astronautics., eds. Dynamics of deflagrations and reactive systems: Heterogeneous combustion. Washington, DC: American Institute of Aeronautics and Astronautics, 1991.

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L, Kuhl A., and American Institute of Aeronautics and Astronautics., eds. Dynamics of deflagrations and reactive systems: Flames. Washington, DC: American Institute of Aeronautics and Astronautics, 1991.

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Paxson, Daniel E. A sectored-one-dimensional model for simulating combustion instabilities in premix combustors. Cleveland, Ohio: National Aeronautics and Space Administration, Glenn Research Center, 1999.

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Paxson, Daniel E. A sectored-one-dimensional model for simulating combustion instabilities in premix combustors. Cleveland, Ohio: National Aeronautics and Space Administration, Glenn Research Center, 1999.

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Paxson, Daniel E. A sectored-one-dimensional model for simulating combustion instabilities in premix combustors. Cleveland, Ohio: National Aeronautics and Space Administration, Glenn Research Center, 1999.

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David, Buckmaster John, Jackson Thomas L. 1957-, Kumar Ajay, Langley Research Center, Institute for Computer Applications in Science and Engineering., and Workshop on Combustion (2nd : 1992 : Hampton, Va.), eds. Combustion in high-speed flows. Dordrecht [The Netherlands]: Kluwer Academic, 1994.

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Book chapters on the topic "Combustion; Flame dynamics"

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Armbruster, Wolfgang, Justin S. Hardi, and Michael Oschwald. "Experimental Investigation of Injection-Coupled High-Frequency Combustion Instabilities." In Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 249–62. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53847-7_16.

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Abstract Self-excited high-frequency combustion instabilities were investigated in a 42-injector cryogenic rocket combustor under representative conditions. In previous research it was found that the instabilities are connected to acoustic resonance of the shear-coaxial injectors. In order to gain a better understanding of the flame dynamics during instabilities, an optical access window was realised in the research combustor. This allowed 2D visualisation of supercritical flame response to acoustics under conditions similar to those found in European launcher engines. Through the window, high-speed imaging of the flame was conducted. Dynamic Mode Decomposition was applied to analyse the flame dynamics at specific frequencies, and was able to isolate the flame response to injector or combustion chamber acoustic modes. The flame response at the eigenfrequencies of the oxygen injectors showed symmetric and longitudinal wave-like structures on the dense oxygen core. With the gained understanding of the BKD coupling mechanism it was possible to derive LOX injector geometry changes in order to reduce the risks of injection-coupled instabilities for future cryogenic rocket engines.
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Gelfand, Boris E., Mikhail V. Silnikov, Sergey P. Medvedev, and Sergey V. Khomik. "Concentration Limits of Flame Propagation." In Thermo-Gas Dynamics of Hydrogen Combustion and Explosion, 73–93. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-25352-2_4.

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Thual, O., U. Frisch, and M. Hénon. "Application of pole decomposition to an equation governing the dynamics of wrinkled flame fronts." In Numerical Simulation of Combustion Phenomena, 389–90. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/bfb0008675.

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Perakis, Nikolaos, and Oskar J. Haidn. "Experimental and Numerical Investigation of CH$$_4$$/O$$_2$$ Rocket Combustors." In Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 359–79. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53847-7_23.

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Abstract The experimental investigation of sub-scale rocket engines gives significant information about the combustion dynamics and wall heat transfer phenomena occurring in full-scale hardware. At the same time, the performed experiments serve as validation test cases for numerical CFD models and for that reason it is vital to obtain accurate experimental data. In the present work, an inverse method is developed able to accurately predict the axial and circumferential heat flux distribution in CH$$_4$$/O$$_2$$ rocket combustors. The obtained profiles are used to deduce information about the injector-injector and injector-flame interactions. Using a 3D CFD simulation of the combustion and heat transfer within a multi-element thrust chamber, the physical phenomena behind the measured heat flux profiles can be inferred. A very good qualitative and quantitative agreement between the experimental measurements and the numerical simulations is achieved.
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Menon, Suresh, Vaidyanathan Sankaran, and Christopher Stone. "Combustion Dynamics of Swirling Turbulent Flames." In Computational Science — ICCS 2001, 1127–36. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/3-540-45545-0_124.

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Joulin, G. "The Complex Dynamics of Wrinkled Flames." In Dissipative Structures in Transport Processes and Combustion, 20–29. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-84230-6_3.

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Rubtsov, Nikolai M., Boris S. Seplyarskii, and Michail I. Alymov. "Gas-Dynamic Factors in Combustion Processes." In Initiation and Flame Propagation in Combustion of Gases and Pyrophoric Metal Nanostructures, 1–60. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-57891-6_1.

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Berestycki, H., B. Larrouturou, and J. M. Roquejoffre. "Mathematical Investigation of the Cold Boundary Difficulty in Flame Propagation Theory." In Dynamical Issues in Combustion Theory, 37–61. New York, NY: Springer New York, 1991. http://dx.doi.org/10.1007/978-1-4612-0947-8_2.

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Frankel, Michael L. "Free Boundary Problems and Dynamical Geometry Associated with Flames." In Dynamical Issues in Combustion Theory, 107–26. New York, NY: Springer New York, 1991. http://dx.doi.org/10.1007/978-1-4612-0947-8_5.

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Antar, Basil N., and Vappu S. Nuotio-Antar. "Combustion and Flame Propagation." In Fundamentals of Low Gravity Fluid Dynamics and Heat Transfer, 235–64. CRC Press, 2019. http://dx.doi.org/10.1201/9781351072182-8.

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Conference papers on the topic "Combustion; Flame dynamics"

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Vishnu, R., R. I. Sujith, and Preeti Aghalayam. "Investigation of Flame Dynamics in a V - Flame Combustor During Combustion Instability." In ASME 2014 Gas Turbine India Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gtindia2014-8345.

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Propulsion systems such as gas turbines are susceptible to combustion instability, when operated at lean equivalence ratio [1]. During combustion instability, there is a nonlinear interaction between combustion and acoustics leading to large amplitude acoustic oscillations. These large amplitude oscillations are detrimental to the stability of the combustor and can cause damages to the structural integrity of the combustor, flame flash back or blow off. The main source of nonlinearity is in the heat release rate caused due to the velocity perturbations at the flame holder [2]. The heat release rate fluctuations are due to the variation in the flame surface area. Hence there is a need to understand the flame dynamics that contributes to the heat release rate fluctuations. The present study aims in understanding the stability of a V - flame combustor by varying the flame location inside an acoustic resonator. By varying the flame location the instability regimes of the combustor are identified. At the flame locations where the system exhibits combustion instability, acoustic pressure oscillations are acquired simultaneously with high speed images of the flame front fluctuations so that a correlation can be made between them. Tools from dynamical systems theory are applied to the pressure signal to quantify different dynamical states of the system during combustion instability. Moreover the flame dynamics at each dynamical state are investigated. It is observed that combustion instability is characterized by interesting dynamical states such as frequency locked state, quasi-periodic oscillations, period 3 oscillations and chaotic oscillations. High speed imaging of the flame reveals different interesting patterns of flame behavior during combustion instability. Flame wrinkling, roll up of flame elements, separation as islands of the flame elements and mutual annihilation of flame elements were some of the interesting flame behavior observed. This study helps in understanding the role of nonlinear heat release rate mechanism in establishing different dynamical states during combustion instability.
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Tropina, Albina, and Richard B. Miles. "Combustion Dynamics of Microwave Enhanced Flame." In 2018 AIAA Aerospace Sciences Meeting. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2018. http://dx.doi.org/10.2514/6.2018-1196.

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Speth, Raymond L., H. Murat Altay, Duane E. Hudgins, and Ahmed F. Ghoniem. "Dynamics and Stability Limits of Syngas Combustion in a Swirl-Stabilized Combustor." In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-51023.

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The combustion dynamics, stability bands and flame structure of syngas flames under different operating conditions are investigated in an atmospheric pressure swirl-stabilized combustor. Pressure measurements and high-speed video data are used to distinguish several operating modes. Increasing the equivalence ratio makes the flame more compact, and in general increases the overall sound pressure level. Very close to the lean blowout limit, a long stable flame anchored to the inner recirculation zone is observed. At higher equivalence ratios, a low frequency, low amplitude pulsing mode associated with the fluid dynamic instabilities of axial swirling flows is present. Further increasing the equivalence ratio produces unstable flames oscillating at frequencies coupled with the acoustic eigenmodes. Additionally, a second unstable mode, coupled with a lower eigen-mode of the system, is observed for flames with CO concentration higher than 50%. As the amount of hydrogen in the fuel is increased, the lean flammability limit is extended and transitions between operating regimes move to lower equivalence ratios.
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Yin, Zhiyao, Peter Kutne, Isaac Boxx, and Wolfgang Meier. "Jet-Oscillation-Induced Combustion Dynamics in a Multi-Nozzle FLOX® Combustor." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75304.

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A 12-nozzle FLOX® combustor is used to generate a full-premixed methane-air flame at ϕ = 0.86 at atmospheric pressure. Combustion stability is examined using 5-kHz simultaneous stereo Planar Image Velocimetry (PIV), OH Planar Laser-induced Fluorescence (OH PLIF) and OH chemiluminescence imaging. Proper Orthogonal Decomposition (POD) of the PIV results from various measurement planes reveals that slow jet oscillations with a characteristic Strouhal number of 0.012 are the dominant fluctuations in the flow field. Jet impingement on and detachment from the walls during jet oscillations are shown to cause the liftoff heights of the flames to increase and decrease. Such changes in flame lift-off heights are also primarily asymmetric among geometrically-symmetric flame pairs. In addition, direct flame-flame interactions are observed as jets collide during oscillations. Dynamic Mode Decomposition (DMD) of the same flow fields is shown able to capture not only the same low-frequency jet-oscillation mode, but also a series of modes spanning the whole resolvable spectrum, which are potential origins of higher-frequency peaks observed in the power spectra of integrated OH chemiluminescence signals.
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Smith, Joshua, Dmitry Suslov, Michael Oschwald, Oskar Haidn, and M. Bechle. "High Pressure LOx/H2 Combustion and Flame Dynamics." In 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2004. http://dx.doi.org/10.2514/6.2004-3376.

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Idahosa, Uyi, Abhishek Saha, Chengying Xu, and Saptarshi Basu. "Characterization of Combustion Dynamics in Swirl Stabilized Flames." In ASME 2009 Power Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/power2009-81168.

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This paper investigates flame frequency response relative to changes in swirl intensity and equivalence ratio in a non-premixed swirl stabilized burner. The degree of swirl in the burner is characterized by the swirl number (S) provided by circumferentially distributed air supply ports directed tangentially to the main axial air flow. Equivalence ratio variations are induced using varying constant, linear ramp and exponentially decaying fuel (propane) flow rates towards blowoff. The variations in the air speed at the exit of the burner (U) are measured with an anemometer located at the base of the flame. The emission of CH* radicals (I) is used as a marker of flame heat release and is measured using a photomultiplier (PMT). The frequency response of the PMT heat release and burner velocity signals are analyzed in the frequency domain using the Fast Fourier Transform (FFT) and Continuous Wavelet Transform (CWT) methods. Amplification in the power of heat release fluctuation is observed in low swirl flames close to blowoff. This effect is found to be reversed in higher swirl number flames even close to blowoff. In dynamic approaches to blowoff (using ramp and decaying fuel flow rates), the dominant heat release fluctuation frequencies are observed to be similar to perturbation frequencies in lean flames hovering at constant fuel flow rates close to blowoff.
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Chorpening, B. T., D. L. Straub, E. D. Huckaby, and K. J. Benson. "Detection of Lean Blowout and Combustion Dynamics Using Flame Ionization." In ASME Turbo Expo 2005: Power for Land, Sea, and Air. ASMEDC, 2005. http://dx.doi.org/10.1115/gt2005-68612.

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The implementation of sophisticated combustion control schemes in modern gas turbines is motivated by the desire to maximize thermodynamic efficiency while meeting NOx emission restrictions. To achieve target NOx levels, modern turbine combustors must operate with a finely controlled fuel-air ratio near the fuel-lean flame extinction limit, where the combustor is most susceptible to instabilities. In turbine configurations with multiple combustors arranged around the annulus, differences in flow splits caused by manufacturing variations or engine wear can compromise engine performance. Optimal combustion control is also complicated by changes in environmental conditions, fuel quality, or fuel type. As a consequence, engines must be commissioned in the field with adequate stability margin such that manufacturing tolerances, normally expected component wear, fuel quality, and environmental conditions will not cause unstable combustion. A lack of robust combustion in-situ monitoring has limited the ability of modern turbines to achieve stable ultra-low emission performance over the entire load range. Of particular concern is the avoidance of lean blowout (LBO) and combustion dynamics. To minimize combustion temperature and NOx production, it is necessary to approach the LBO boundary. This paper describes continuing work on incipient lean blowout detection using flame ionization, investigating the impact of three different piloting and equivalence ratio reduction strategies applied in a pressurized, lean premixed combustor. This work builds upon previous research in the development of the Combustion Control and Diagnostic Sensor (CCADS). In previous papers, the detection of flashback, equivalence ratio, combustion dynamics, and lean blowout using CCADS has been investigated and described. Previous investigation of lean blowout, however, has been limited to a side pilot configuration. In this paper, lean blowout behavior for a side pilot and a centerbody tip pilot are compared. In addition, two different methods for decreasing equivalence ratio to approach LBO are investigated. These cases are found to have differing lean blowout behavior, and differing CCADS signatures. This paper also reports on the ion signal behavior due to combustion dynamics observed during the equivalence ratio sweeps, including passing through stability boundaries. Tests were performed at 5 atm using an industrial style, lean premixed combustor nozzle, equipped with CCADS electrodes, in a water-cooled, natural gas fueled, acoustically noisy combustor. Testing included sweeps of equivalence ratio from 0.65 to 0.45, crossing one or more stability boundaries. LBO was approached for configurations with a side pilot (on the inlet wall of the combustor, but set away from the premixer) and a centerbody tip pilot. The centerbody tip pilot and the side pilot both helped stabilize combustion, but combustion dynamics still occurred. Incipient LBO was apparent in all cases; however, the different flame structure encountered with each pilot configuration and fuel control strategy made the flame ionization signature differ for each case.
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Zhu, Shengrong, and Sumanta Acharya. "Dynamics of Lean Blowout in Premixed Combustion With Hydrogen Addition." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-69189.

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An experimental study of lean premixed combustion in a swirl-stabilized combustor is undertaken to characterize the dynamics and time scales close to Lean Blow Out (LBO) conditions. Due to the recent interest in syngas fuels, the effect of hydrogen addition on LBO is studied. In present study, both confined and unconfined turbulent methane air premixed flames have been examined with different hydrogen levels during the extinction transition with high speed imaging of OH* chemiluminescence at 2 KHz. Planar laser induced fluorescence measurement of OH is also performed for studying the flame structure. The blowout conditions are approached by reducing the flow rate of fuel mixture or the equivalence ratio with constant air flow rate. The estimated extinction times from high speed imaging and corresponding flame structures are analyzed and compared between confined and unconfined flames with different hydrogen blends. The extinction time scale and the heat release fluctuations show inverse trends with hydrogen addition for the confined and unconfined flames, and are indicative of different stabilization and blow out mechanisms for the two configurations. These mechanisms which involve heat losses from the flame, inner- and corner recirculation zones and unsteady flame dynamics are described in the paper.
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Milan, Petro Junior, Reetesh Ranjan, Achyut Panchal, and Suresh Menon. "Flame Dynamics Sensitivity to Turbulent Combustion Models in a Swirl Spray Combustor." In 53rd AIAA/SAE/ASEE Joint Propulsion Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2017. http://dx.doi.org/10.2514/6.2017-5079.

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Saurabh, Aditya, and C. O. Paschereit. "Combustion Instability in a Swirl Flow Combustor With Transverse Extensions." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95732.

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The present investigation is an analysis of self-excited combustion instability in a swirl flame-based combustor with transverse extensions. Transverse extensions create the possibility of studying flame interaction with transverse acoustic oscillations. Such investigation important for understanding the phenomenon of thermoacoustic instability in annular combustors, where during thermoacoustic instability, azimuthal acoustic modes of the combustor couple with the multiple flames of the combustor. Flame and flow field dynamics during self-excited thermoacoustic instability in the single burner test-rig is presented here. These results are then compared to the dynamics of the isothermal and reacting flows in response to axial and transverse acoustic forcing. Both axial and transverse forcing led to the formation of axisymmetric shear layer vortices. Adding to the insight gained from previous investigations, these results suggest that that swirl flow dynamics in response to transverse acoustics consists of a non-trivial, direct effect of transverse acoustics on the flow field, in addition to its response to longitudinal fluctuations induced by transverse forcing.
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Reports on the topic "Combustion; Flame dynamics"

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Ihme, Matthias, and James Driscoll. Development and Experimental Validation of Large Eddy Simulation Techniques for the Prediction of Combustion-Dynamic Process in Syngas Combustion: Characterization of Autoignition, Flashback, and Flame-Liftoff at Gas-Turbine Relevant Operating Conditions. Office of Scientific and Technical Information (OSTI), August 2015. http://dx.doi.org/10.2172/1337558.

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