... transformed quantity References [1] Stow , S. R. , and Dowling , A. P. , 2001 , “ Thermoacoustic Oscillations in an Annular Combustor ,” ASME Paper No. 2001-GT-0037. 10.1115/2001-GT-0037 [2] Nicoud , F. , Benoit , L. , Sensiau , C. , and Poinsot , T. , 2007...

... on the thermoacoustic frequencies of the combustor. We show how this communication gives rise to axial and azimuthal modes, and that these correspond to particularly synchronized states of axial thermoacoustic oscillations in each individual can. We show that these combustors typically show clusters of thermoacoustic...

... Experimental Flame Modeling Thermoacoustics Pilot flames have been traditionally used for improving the lean blowout limits of the gas turbine combustors [ 1 – 10 ]. Effects of pilot flames on improving the static stability have been extensively studied and well understood, with literatures...

.... Comput. Phys. , 283 , pp. 312 – 328 . 10.1016/j.jcp.2014.12.010 [33] Giauque , A. , Huet , M. , Clero , F. , Ducruix , S. , and Richecoeur , F. , 2013 , “ Thermoacoustic Shape Optimization of a Subsonic Nozzle ,” ASME J. Eng. Gas Turbines Power , 135 (10), p. 102601...

... in a combustor where a turbulent flame acts as a thermoacoustic driver. In the proposed approach, the unfiltered pressure signal including several modes is analyzed by an algorithm based on Bayesian statistics. For this purpose, a Gibbs sampler is used to calculate parameters like damping rates...

... Gas turbine technology Thermoacoustics Turbulence Unsteady flows The multiscale nature of combustion dynamics and their coupling mechanisms makes the experimental investigation of the phenomena challenging. High thermal power density flames present in gas turbine combustors are naturally...

... manuscript received September 21, 2017; published online May 4, 2018. Editor: David Wisler. 16 08 2017 21 09 2017 Acoustic emission Combustion Thermoacoustics Combustion noise is at the heart of several efforts to reduce aircraft emissions. First, as large reductions in jet...

... thermo-acoustic instability at 500 Hz with an associated flame motion completely similar to the previous one. The rotational motions can no longer be detected in the flame behavior, probably because of the high amplitude fluctuations induced by the thermoacoustic instability. Using Hilbert transform...

... of each method, validation is made with the available measured data for the pressure and vibration signals, showing that the thermoacoustic instabilities are well predicted using the CHT and two-way coupled approaches, while the zero-way interaction model prediction gives the largest discrepancy from...

...D. Ebi; A. Denisov; G. Bonciolini; E. Boujo; N. Noiray We report experimental evidence of thermoacoustic bistability in a lab-scale turbulent combustor over a well-defined range of fuel–air equivalence ratios. Pressure oscillations are characterized by an intermittent behavior with “bursts,” i.e...

...Georg A. Mensah; Luca Magri; Jonas P. Moeck Thermoacoustic instabilities are a major threat for modern gas turbines. Frequency-domain-based stability methods, such as network models and Helmholtz solvers, are common design tools because they are fast compared to compressible flow computations...

...Tobias Hummel; Frederik Berger; Nicolai Stadlmair; Bruno Schuermans; Thomas Sattelmayer This paper presents a set of methodologies for the extraction of linear growth and damping rates associated with transversal eigenmodes at screech level frequencies in thermoacoustically noncompact gas turbine...

...Vera Hoferichter; Thomas Sattelmayer Lean premixed combustion is prevailing in gas turbines to minimize nitrogen oxide emissions. However, this technology bears the risk of flame flashback and thermoacoustic instabilities. Thermoacoustic instabilities induce velocity oscillations at the burner exit...

...Frederik M. Berger; Tobias Hummel; Bruno Schuermans; Thomas Sattelmayer This paper presents the experimental investigation of pulsation-amplitude-dependent flame dynamics associated with transverse thermoacoustic oscillations at screech level frequencies in a generic gas turbine combustor...

... length and velocity scales of a turbulent flame change with bulk flow velocity. A simple relation that predicts how ITA resonance frequencies should increase with bulk flow velocity compares well with experimental results. Convection Flame Swirling Thermoacoustics Stricter emission...

... and acoustics, which lead under certain conditions to thermoacoustic instabilities [ 30 ]. These coupling effects can be described in terms of a flame transfer function, which is, however, not available from experimental measurements or LES computations. Consequently the different contributions in the spectrum...

... dynamics Convection Engines Flame Modeling Swirling Thermoacoustics Unsteady flows Wave propagation Coupled behavior Combustion instabilities (CI) are a serious concern in the design process of aeronautical engines. They are still hard to predict and, as a consequence, generally appear...

... URBINES AND P OWER . Manuscript received July 4, 2017; final manuscript received July 18, 2017; published online October 17, 2017. Editor: David Wisler. 04 07 2017 18 07 2017 Aeronautical propulsion Combustion Droplet Experimental Sprays Swirling Thermoacoustics Turbulent Two...

.... Editor: David Wisler. 06 07 2017 26 07 2017 Combustion Combustors Experimental Flame Thermoacoustics Lean-premixed gas turbines used for power generation purposes are prone to combustion instabilities caused by their design and operation [ 1 ]. These instabilities...

... (SPOD). The results show that the transitions are governed by two types of instability, namely a hydrodynamic instability in the form of a precessing vortex core (PVC) and a thermoacoustic (TA) instability. The LSA shows that the V-M transition implies the transient formation of a PVC as the result...