Article
Thermodynamics
T. Schuller, S. Marragou, G. Oztarlik, T. Poinsot, L. Selle
Summary: The dynamics of hydrogen-enriched V-shape swirled lean premixed methane/air flames are investigated for different injection schemes. It is found that the response of the flames varies significantly depending on whether hydrogen is premixed with the main flow or injected pure as a pilot jet. The flame behavior is found to be influenced by the reactivity of the hydrogen-enriched mixture and the distribution of heat release along the flame brush.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
A. Aniello, D. Laera, S. Marragou, T. Poinsot, T. Schuller, L. Selle
Summary: This study investigates the impact of localized pilot hydrogen injection on the Flame Transfer Function (FTF) of a premixed methane-air swirled flame using Large Eddy Simulation. The results show that hydrogen injection leads to a global redistribution of the heat release rate, resulting in a reduction of the FTF gain over the entire frequency range. In addition, hydrogen injection affects the characteristic time lag of the flame response.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Markus Weilenmann, Ulrich Doll, Rolf Bombach, Audrey Blonde, Dominik Ebi, Yuan Xiong, Nicolas Noiray
Summary: Broadband combustion noise from modern jet engines includes direct noise from unsteady heat release and indirect noise from entropy wave acceleration. This study quantitatively measures the production of entropy waves in a technically premixed turbulent combustor under acoustic forcing, revealing nonlinear production characteristics of entropy waves with certain burners.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Karthik Bhairapurada, Bruno Denet, Pierre Boivin
Summary: This study presents possibly the first use of lattice-Boltzmann numerical simulations to investigate thermo-acoustic instabilities of premixed flames. The study examines the interaction between flames and an imposed acoustic field, observing the effects of parametric instability on flames and the influence of the acoustic forcing on plane flames. It also explores self-induced thermo-acoustic oscillations of flames propagating in narrow channels, revealing an unexpected dependency on channel width. The results confirm the capability of the lattice-Boltzmann method to capture the complex coupling between flame dynamics and acoustics.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
C. Laurent, G. Staffelbach, F. Nicoud, T. Poinsot
Summary: Large Eddy Simulations were used to study the heat-release response of a coaxial jet flame to fuel inflow acoustic harmonic oscillations. The study found that the flame response is highly dependent on forcing frequency, with heat release fluctuations primarily coming from species diffusivity oscillations.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Roeland Wildemans, Viktor Kornilov, Philip de Goey, Ines Lopez Arteaga
Summary: In this study, the nonlinear dynamics of pure Intrinsic Thermo-Acoustic (ITA) modes in burner stabilized premixed flames are experimentally investigated by decoupling them from the acoustic modes. The setup with up- and downstream mufflers provides anechoic boundary conditions, enabling the study of self-excited flame oscillations without acoustic reflections. Bifurcation analysis is conducted to systematically investigate different oscillatory states and transitions, revealing various phenomena such as supercritical Hopf bifurcation and period doubling bifurcation.
COMBUSTION AND FLAME
(2023)
Article
Mechanics
D. Fredrich, W. P. Jones, A. J. Marquis
Summary: This paper investigates the combined effects of thermo-acoustic and hydrodynamic instability mechanisms on self-excited combustion instabilities in gas turbine combustors. Through compressible large eddy simulation, the study successfully captures oscillation phenomena and confirms agreement with experimental data. Analysis reveals the impact of mass flow rate and equivalence ratio fluctuations on governing feedback loops, as well as the control of hydrodynamic phenomena by oscillation of the swirl number. The study also describes the temporal relationship between flame surface area, mixture fraction, and heat release rate.
Article
Thermodynamics
F. Baillot, C. Patat, M. Caceres, J. -B. Blaisot, E. Domingues
Summary: This paper investigates the response of a central flame to acoustic pressure in a linearly-arranged multiple-injection system, identifying three zones of linear growth, transition, and saturation as the aerodynamic pressure changes. The flame response shows a degradation in intensity level and uniformity over time in the saturation zone, indicating a loss of robustness. The aerodynamics in the gas phase can disrupt mixing processes, while the liquid-phase displays severe modulation in droplet distribution and properties at high aerodynamic pressures.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Guillaume Vignat, Daniel Durox, Antoine Renaud, Thea Lancien, Ronan Vicquelin, Sebastien Candel
Summary: The dynamics of the Precessing Vortex Core (PVC) in flame formation were investigated using laser sheet illumination and analysis methods, revealing characteristics of double helix and triple helix geometries. By increasing the chamber length, cyclic motion of flames in the inner recirculation zone was observed, with the PVC being modulated in amplitude and frequency by combustion instability and longitudinal acoustic modes. The PVC was also found to vanish in a random manner, indicating complex interactions in the combustion process.
COMBUSTION AND FLAME
(2021)
Article
Thermodynamics
Eirik Aesoy, Hakon T. Nygard, Nicholas A. Worth, James R. Dawson
Summary: This study investigates how targeted interference between two well-characterized sources of hydrodynamic disturbances can modify the response of premixed bluff-body stabilized H-2/CH4 flames with and without swirl. The Flame Transfer Function (FTF) can be modulated at targeted frequencies by placing different shaped bodies upstream of the flame and varying the distance from the dump plane. The flame response shows that modulations in the fluctuating global heat release rate are caused by linear superposition along the flame front, leading to changes in flame surface area and amplitude of the fluctuating global heat release rate.
COMBUSTION AND FLAME
(2022)
Article
Engineering, Mechanical
Roeland Wildemans, Viktor Kornilov, Ines Lopez Arteaga
Summary: A nonlinear phenomenological model consisting of two coupled oscillators is proposed to describe the rich nonlinear behavior of a simple combustion system. The model accurately reproduces the different observed regimes, including supercritical Hopf bifurcation, limit cycle, quasi-periodic, and period-2 limit cycle oscillations. Parameter estimation shows a good quantitative match between the model response and experimental data, suggesting that the model effectively captures the nonlinear self-excited acoustic behavior of premixed flames.
NONLINEAR DYNAMICS
(2023)
Article
Thermodynamics
F. Collin-Bastiani, E. Riber, B. Cuenot
Summary: This study focuses on inter-injector spray flame propagation in a linear multi-injector n-heptane/air spray burner, using Large Eddy Simulation and complex chemistry description to investigate the influence of inter-injector spacing on flow dynamics and local fuel distribution. The results suggest that the characteristics of inter-injector spray propagation can be accurately captured by LES, with important pre-evaporation impacting the ignition process.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Weijie Liu, Ranran Xue, Liang Zhang, Qian Yang, Huiru Wang
Summary: This experimental study investigates the nonlinear response of a premixed methane/air low-swirl flame to imposed acoustic excitation, revealing complex amplitude dependence of the flame at different frequencies and the influence of flame dynamics due to flame rollup and shear layer instabilities.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Eirik Aesoy, Thomas Indlekofer, Francesco Gant, Alexis Cuquel, Mirko R. Bothien, James R. Dawson
Summary: This study investigates the effects of hydrogen enrichment, flame-flame interaction, confinement, and asymmetries on the acoustic response of flames in a combustor. The results show that increasing hydrogen enrichment has a significant effect on flame response, while the effect of injector spacing is relatively smaller. Asymmetry also affects flame response, but asymmetric cases can be reconstructed using the superposition of symmetric cases.
COMBUSTION AND FLAME
(2022)
Article
Chemistry, Multidisciplinary
Deng Pan, Chenzhen Ji, Tong Zhu
Summary: This study experimentally investigates the nonlinear heat release response of a methane-air non-premixed flame to low-frequency acoustic excitations. The flame describing function (FDF) is measured using CH* chemiluminescence intensity and velocity fluctuations. The study finds that the flame length is more sensitive to changes in excitation amplitude when subjected to high-frequency excitations.
APPLIED SCIENCES-BASEL
(2023)
Article
Thermodynamics
Gorkem Oztarlik, Laurent Selle, Thierry Poinsot, Thierry Schuller
COMBUSTION AND FLAME
(2020)
Article
Thermodynamics
G. Vignat, D. Durox, T. Schuller, S. Candel
COMBUSTION SCIENCE AND TECHNOLOGY
(2020)
Article
Mechanics
Thierry Schuller, Thierry Poinsot, Sebastien Candel
JOURNAL OF FLUID MECHANICS
(2020)
Article
Thermodynamics
Fabien Dupuy, Marco Gatti, Clement Mirat, Laurent Gicquel, Franck Nicoud, Thierry Schuller
COMBUSTION AND FLAME
(2020)
Article
Thermodynamics
A. Degeneve, R. Vicquelin, C. Mirat, J. Caudal, T. Schuller
Summary: The direction of swirl has a significant impact on the flame shape and the intensity of the central recirculation zone in non-premixed oxy-flames. Counter-swirl leads to longer flames, while co-swirl produces more compact flames.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
D. Laera, P. W. Agostinelli, L. Selle, Q. Cazeres, G. Oztarlik, T. Schuller, L. Gicquel, T. Poinsot
Summary: High-fidelity Large Eddy Simulations (LES) were used to study the impact of hydrogen injection on a lean turbulent CH4/Air premixed flame, with an Analytically Reduced Chemistry (ARC) mechanism and different transport modeling strategies. The results showed large variations in mixture properties and flame structure, highlighting the importance of using complex transport properties in LES involving hydrogen combustion.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
A. Cellier, C. J. Lapeyre, G. Oztarlik, T. Poinsot, T. Schuller, L. Selle
Summary: This study introduces a tool based on Deep Learning techniques to detect and translate TAI precursors in a swirled combustor for different fuel injection strategies. The tool offers real-time information on the system's margin versus TAI and allows for adjustments in operating conditions to avoid instability.
COMBUSTION AND FLAME
(2021)
Article
Chemistry, Physical
S. Marragou, H. Magnes, T. Poinsot, L. Selle, T. Schuller
Summary: This study investigates the stability and pollutant emissions of burning hydrogen in gas turbines. The results show that introducing swirl in the central hydrogen stream can achieve aerodynamically stabilized flames and reduce thermal stress and NOx emissions on the burner. Moreover, a small recess in the hydrogen injector extends the operability range of the burner and keeps NOx emissions low even with pure hydrogen.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Physical
A. Aniello, T. Poinsot, L. Selle, T. Schuller
Summary: This study investigates the effects of hydrogen addition on the stability and flashback occurrence of two different multi-perforated premixed burners designed for natural gas. The results show that hydrogen addition increases the blow off resistance of the burners, but also raises the risk of flashback. It is found that the occurrence of flashback is closely related to the surface temperature of the burners.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Thermodynamics
Tarik Yahou, James R. Dawson, Thierry Schuller
Summary: The study investigates the impact of chamber back pressure and H2-enrichment on flashback of premixed CH4-H2-Air flames triggered by ignition dynamics. Different scenarios are identified, including soft ignition with direct stabilisation, transient flashback, and permanent flashback. H2-enrichment affects the stabilisation mode of the flame, while the over pressure generated at ignition is amplified by small increases in mean back pressure, promoting flashback. The study highlights the need for a new mechanism to fully describe flashback triggered by ignition dynamics.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Chemistry, Physical
H. Pers, A. Aniello, F. Morisseau, T. Schuller
Summary: This study investigates the possibility of autoignition as a flashback initiation mechanism in premixed burners with increasing hydrogen content. Experimental observations reveal the existence of two distinct initiation regimes: flame propagation upstream and autoignition along the hot burner wall. The results highlight the dependence of the initiation regime on the burner wall temperature and the role of the crossover temperature of hydrogen-enriched mixtures in triggering autoignition.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Thermodynamics
Sylvain Marragou, Herve Magnes, Andrea Aniello, Laurent Selle, Thierry Poinsot, Thierry Schuller
Summary: This study investigates the stabilization mechanisms of partially premixed H2/air flames on a coaxial dual swirl injector under atmospheric conditions. Different flame stabilization modes are observed depending on the injector's geometry and operating conditions. The flame can either stabilize on the injector lips as a diffusion flame or be lifted from the injector and burn mainly in a partially premixed regime.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
A. Aniello, D. Laera, S. Marragou, T. Poinsot, T. Schuller, L. Selle
Summary: This study investigates the impact of localized pilot hydrogen injection on the Flame Transfer Function (FTF) of a premixed methane-air swirled flame using Large Eddy Simulation. The results show that hydrogen injection leads to a global redistribution of the heat release rate, resulting in a reduction of the FTF gain over the entire frequency range. In addition, hydrogen injection affects the characteristic time lag of the flame response.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
S. Marragou, H. Magnes, A. Aniello, T. F. Guiberti, L. Selle, T. Poinsot, T. Schuller
Summary: A model based on the triple flame speed is used to predict the stabilization regime of partially premixed H2/air flames above an injector. The model is applied to a coaxial dual swirl injector, and the predictions agree well with the observations, providing a simple framework for flame stabilization prediction on coaxial injectors.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
T. Moriniere, L. Selle, T. Poinsot, T. Schuller
Summary: The acoustic flux at the inlet of the combustion chamber is used as an indicator for impending thermo-acoustic instabilities (TAI) in a swirled spray combustor. The acoustic flux exhibits significant magnitude changes and shape evolutions when approaching TAI, while being relatively insensitive to modifications in signal processing parameters.
COMBUSTION SCIENCE AND TECHNOLOGY
(2023)