Blar i NTNU Open på forfatter "Moeck, Jonas"
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Actuation efficiency of nanosecond repetitively pulsed discharges for plasma-assisted swirl flames at pressures up to 3 bar
Di Sabatino, Francesco; Guiberti, Thibault; Moeck, Jonas; Roberts, William; Lacoste, Deanna (Peer reviewed; Journal article, 2021)This study analyzes different strategies of plasma actuation of premixed swirl flames at pressures up to 3 bar. A wide range of applied voltages and pulse repetition frequencies (PRF) is considered, resulting in different ... -
Analysis of Thermoacoustic Modes in Can-Annular Combustors Using Effective Bloch-Type Boundary Conditions
von Saldern, Jakob; Orchini, Alessandro; Moeck, Jonas (Peer reviewed; Journal article, 2020)Heavy-duty gas turbines are commonly designed with can-annular combustors, in which all flames are physically separated. Acoustically, however, the cans communicate via the upstream located compressor plenum, or at the ... -
Computation and prediction of intrinsic thermoacoustic oscillations associated with autoignition fronts
Gopalakrishnan, Harish Subramanian; Gruber, Andrea; Moeck, Jonas (Peer reviewed; Journal article, 2023)A sequential combustor architecture consists of two longitudinally staged combustion zones featuring a propagation-stabilized flame in the first stage and an autoignition-stabilized flame in the second (reheat) stage. This ... -
Computation of Intrinsic Instability and Sound Generation From Autoignition Fronts
Gopalakrishnan, Harish Subramanian; Gruber, Andrea; Moeck, Jonas (Peer reviewed; Journal article, 2022)Burning carbon-free fuels such as hydrogen in gas turbines promise power generation with minimal emissions of greenhouse gases. A two-stage sequential combustor architecture with a propagation-stabilized flame in the first ... -
Degenerate perturbation theory in thermoacoustics: high-order sensitivities and exceptional points
Orchini, Alessandro; Magri, Luca; Silva, Camilo F.; Mensah, Georg; Moeck, Jonas (Peer reviewed; Journal article, 2020)In this study, we connect concepts that have been recently developed in thermoacoustics, specifically (i) high-order spectral perturbation theory, (ii) symmetry-induced degenerate thermoacoustic modes, (iii) intrinsic ... -
Effect of an Azimuthal Mean Flow On the Structure and Stability of Thermoacoustic Modes in an Annular Combustor Model with Electroacoustic Feedback
Humbert, Sylvain; Moeck, Jonas; Orchini, Alessandro; Paschereit, Oliver (Peer reviewed; Journal article, 2020)Thermoacoustic oscillations in axisymmetric annular combustors are generally coupled by degenerate azimuthal modes, which can be of standing or spinning nature. Symmetry breaking due to the presence of a mean azimuthal ... -
The Effect of Hydrogen Enrichment on the Thermoacoustic Behaviour of Lean Premixed Flames
Æsøy, Eirik (Doctoral theses at NTNU;2022:23, Doctoral thesis, 2022)Gas turbines (GT) burning hydrogen can help deliver large-scale zero carbon power generation and facilitate rapid decarbonisation over the short to medium term. They can also play a crucial role in increasing the penetration ... -
Effect of noise and nonlinearities on thermoacoustics of can-annular combustors
Ghirardo, Giulio; Moeck, Jonas; Bothien, Mirko R. (Peer reviewed; Journal article, 2020)Can-annular combustors consist of N distinct cans setup symmetrically around the axis of the gas turbine. Each can is connected to the turbine inlet by means of a transition duct. At the turbine inlet, a small gap between ... -
Fuel and Equivalence Ratio Effects on Transfer Functions of Premixed Swirl Flames
Di Sabatino, Francesco; Guiberti, Thibault; Moeck, Jonas; Roberts, William; Lacoste, Deanna (Peer reviewed; Journal article, 2020)This paper reports on the effects of fuel and equivalence ratio on the response of lean premixed swirl flames to acoustic perturbations of the flow, at atmospheric pressure. The response is analyzed using flame transfer ... -
Intrinsic thermoacoustic modes in an annular combustion chamber
Buschmann, Philip Erik; Mensah, Georg; Moeck, Jonas (Peer reviewed; Journal article, 2020)Thermoacoustic instabilities originate from the interaction of unsteady heat release rate associated with flames and the acoustic modes of a combustor. A feedback loop not involving the natural acoustic modes has been ... -
Linear Flow Analysis Inspired by Mathematical Methods from Quantum Mechanics
Magri, Luca; Schmid, Peter; Moeck, Jonas (Peer reviewed; Journal article, 2022)Since its birth in the 1920s, quantum mechanics has motivated and advanced the analysis of linear operators. In this effort, it significantly contributed to the development of sophisticated mathematical tools in spectral ... -
A Non-Compact Effective Impedance Model for Can-To-Can Acoustic Communication: Analysis and Optimization of Damping Mechanisms
von Saldern, Jakob; Orchini, Alessandro; Moeck, Jonas (Peer reviewed; Journal article, 2021)Can-annular combustors can feature azimuthal instabilities even if the acoustic coupling between the individual cans is weak. Recently, various studies have focused on modeling the acoustic communication between adjacent ... -
Nonlinear interaction between clustered unstable thermoacoustic modes in can-annular combustors
von Saldern, Jakob; Moeck, Jonas; Orchini, Alessandro (Peer reviewed; Journal article, 2020)A can-annular combustor consists of a set of nominally identical cans, in which the flames burn in an essentially isolated manner. However, adjacent cans are able to communicate acoustically, which provides dynamic coupling ... -
The Nonlinear Thermoacoustic Eigenvalue Problem and Its Rational Approximations: Assessment of Solution Strategies
Merk, Moritz; Buschmann, Philip Erik; Moeck, Jonas; Polifke, Wolfgang (Peer reviewed; Journal article, 2022)Nonlinear eigenvalue problems (NLEVPs) arise in thermoacoustics by considering the temporal evolution of small perturbations in the relevant governing equations. In this work, two solution strategies are compared: (i) a ... -
On the role of symmetry and degeneracy in nonlinear thermoacoustic eigenproblems with application to can-annular combustors
Buschmann, Philip Erik (Doctoral theses at NTNU;2022:30, Doctoral thesis, 2022)The subject of this dissertation are thermoacoustic instabilities in combustion chambers with discrete rotational and reflective symmetries. Designing thermoacoustically stable combustors is one of the principal challenges ... -
Perturbation theory of nonlinear, non-self-adjoint eigenvalue problems: Semisimple eigenvalues
Orchini, Alessandro; Mensah, Georg; Moeck, Jonas (Peer reviewed; Journal article, 2021)We discuss high-order adjoint based degenerate perturbation theory of semisimple eigenvalues resulting from nonlinear eigenvalue problems, which are typical of acoustic problems and vibrational analysis. The theory is ... -
Perturbation theory of nonlinear, non-self-adjoint eigenvalue problems: Simple eigenvalues
Mensah, Georg; Orchini, Alessandro; Moeck, Jonas (Peer reviewed; Journal article, 2020)The study of the vibrational modes and stability of a given physical system is strongly tied to the efficient numerical evaluation of its eigenvalues. The operators governing the eigenproblem are, in general, nonlinear in ... -
The Rayleigh integral is always positive in steadily operated combustors
Schuermans, Bruno; Moeck, Jonas; Blonde, Audrey; Dharmaputra, Bayu; Noiray, Nicolas (Peer reviewed; Journal article, 2022)The Rayleigh index has been used for decades by a large number of researchers as an indicator to determine if a flame is driving or damping thermoacoustic interaction mechanisms. The use of the Rayleigh criterion has found ... -
Reduced-order modelling of thermoacoustic instabilities in can-annular combustors
Orchini, Alessandro; Pedergnana, Tiemo; Buschmann, Philip Erik; Moeck, Jonas; Noiray, Nicolas (Peer reviewed; Journal article, 2022)Thermoacoustic instabilities in stationary gas turbines may cause high-amplitude limit cycles, leading to damaged components and costly down-time. To better understand the physical origin of such instabilities in a can-annular ... -
Response of Autoignition-Stabilized Flames to One-Dimensional Disturbances: Intrinsic Response
Gopalakrishnan, Harish Subramanian; Gruber, Andrea; Moeck, Jonas (Peer reviewed; Journal article, 2021)Burning carbon-free fuels such as hydrogen in gas turbines promises power generation with strongly reduced greenhouse gas emissions. A two-stage combustor architecture with a propagation-stabilized flame in the first stage ...