scholarly journals Design and Decomposition Analysis of Mixing Zone Structures on Flame Dynamics for a Swirl Burner

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6744
Author(s):  
Yang Yang ◽  
Zhijian Yu
Keyword(s):  
Transfer Functions ◽  
Decomposition Analysis ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Streamwise Vortices ◽  
Frequency Bands ◽  
Time Dynamic ◽  
Burner Exit ◽  
Decomposition Procedure ◽  
Flame Structures

The recirculation zone and the swirl flame behavior can be influenced by the burner exit shape, and few studies have been made into this structure. Large eddy simulation was carried out on 16 cases to distinguish critical geometry factors. The time series of the heat release rate were decomposed using seasonal-trend decomposition procedure to exclude the effect of short physical time. Dynamic mode decomposition (DMD) was performed to separate flame structures. The frequency characteristics extracted from the DMD modes were compared with those from the flame transfer functions. Results show that the flame cases can be categorized into three types, all of which are controlled by a specific geometric parameter. Except one type of flame, they show nonstationary behavior by the Kwiatkowski–Phillips–Schmidt–Shin test. The frequency bands corresponding to the coherent structures are identified. The flame transfer function indicates that the flame can respond to external excitation in the frequency range 100–300 Hz. The DMD modes capture the detailed flame structures. The higher frequency bands can be interpolated as the streamwise vortices and shedding vortices. The DMD modes, which correspond to the bands of flame transfer functions, can be estimated as streamwise vortices at the edges.

Modal Decomposition Analysis of Combustion Instability Due to External Perturbation in a Mesoscale Burner Array

2022 ◽  
Author(s):  
Jeongan Choi ◽  
Rajavasanth Rajasegar ◽  
Qili Liu ◽  
Tonghun Lee ◽  
Jihyung Yoo
Keyword(s):  
Growth Rates ◽  
High Speed ◽  
Combustion Instability ◽  
Decomposition Analysis ◽  
External Perturbation ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Combustion Instabilities ◽  
Thermoacoustic Instability ◽  
Growth Regime

Abstract In this work, the growth regime of combustion instability was studied by analyzing 10 kHz OH planar laser induced fluorescence (PLIF) images through a combination of dynamic mode decomposition (DMD) and spectral proper orthogonal decomposition (SPOD) methods. Combustion instabilities were induced in a mesoscale burner array through an external speaker at an imposed perturbation frequency of 210 Hz. During the transient onset of combustion instabilities, 10 kHz OH PLIF imaging was employed to capture spatially and temporally resolved flame images. Increased acoustic perturbations prevented flame reignition in the central recirculation zone and eventually led to the flame being extinguished inwards from the outer burner array elements. Coherent modes and their growth rates were obtained from DMD spectral analyses of high-speed OH PLIF images. Positive growth rates were observed at the forcing frequency during the growth regime. Coherent structures, closely associated with thermoacoustic instability, were extracted using an appropriate SPOD filter operation to identify mode structures that correlate to physical phenomena such as shear layer instability and flame response to longitudinal acoustic forcing. Overall, a combination of DMD and SPOD was shown to be effective at analyzing the onset and propagation of combustion instabilities, particularly under transient burner operations.

Dynamic Mode Decomposition Analysis of High-Fidelity CFD Simulations of the Sinus Ventilation

2020 ◽  
Vol 105 (3) ◽  
pp. 699-713 ◽  
Author(s):  
Hadrien Calmet ◽  
Daniel Pastrana ◽  
Oriol Lehmkuhl ◽  
Takahisa Yamamoto ◽  
Yoshiki Kobayashi ◽  
...  
Keyword(s):  
Decomposition Analysis ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
High Fidelity ◽  
Cfd Simulations ◽  
Mode Decomposition

The Effects of Turbulent Burning Velocity Models in a Swirl-Stabilized Lean Premixed Combustor

2018 ◽  
Vol 35 (4) ◽  
pp. 365-372
Author(s):  
Jong-Chan Kim ◽  
Won-Chul Jung ◽  
Ji-Seok Hong ◽  
Hong-Gye Sung
Keyword(s):  
Burning Velocity ◽  
Premixed Combustion ◽  
Dynamic Mode Decomposition ◽  
Combustion Model ◽  
Dynamic Mode ◽  
Turbulent Premixed Combustion ◽  
Velocity Models ◽  
Flame Structures ◽  
Turbulent Burning Velocity ◽  
Turbulent Premixed

Abstract The effects of turbulent burning velocities in a turbulent premixed combustion simulation with a G-equation are investigated using the 3D LES technique. Two turbulent burning velocity models – Kobayashi model, which takes into account the burning velocity pressure effect, and the Pitsch model, which considers the flame regions on the premixed flame structure – are implemented. An LM6000 combustor is employed to validate the turbulent premixed combustion model. The results show that the flame structures in front of the injector have different shapes in each model because of the different turbulent burning velocities. These different flame structures induce changes in the entire combustor flow field, including in the recirculation zone. The dynamic mode decomposition (DMD) method and linear acoustic analysis provide the dominant acoustic mode.

Dynamic mode decomposition analysis for Savonius wind turbine

2019 ◽  
Vol 11 (6) ◽  
pp. 063307
Author(s):  
Mohammad Hossein Naderi ◽  
Mojtaba Tahani ◽  
Vahid Esfahanian
Keyword(s):  
Wind Turbine ◽  
Decomposition Analysis ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Mode Decomposition ◽  
Savonius Wind Turbine

scholarly journals Analysis and Modelling of Entropy Modes in a Realistic Aeronautical Gas Turbine

2013 ◽  
Author(s):  
Emmanuel Motheau ◽  
Franck Nicoud ◽  
Yoann Mery ◽  
Thierry Poinsot
Keyword(s):  
Transfer Functions ◽  
Acoustic Mode ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Acoustic Coupling ◽  
Eddy Simulation ◽  
Mode Decomposition ◽  
Exit Nozzle ◽  
Large Eddy ◽  
Aero Engines

A combustion instability in a combustor typical of aero-engines is analyzed and modeled thanks to a low order Helmholtz solver. A Dynamic Mode Decomposition (DMD) is first applied to the Large Eddy Simulation (LES) database. The mode with the highest amplitude shares the same frequency of oscillation as the experiment (approx. 350 Hz) and it shows the presence of large entropy spots generated within the combustion chamber and convected down to the exit nozzle. The lowest purely acoustic mode being in the range 650–700 Hz, it is postulated that the instability observed around 350 Hz stems from a mixed entropy/acoustic mode where the acoustic generation associated with the entropy spots being convected throughout the choked nozzle plays a key role. A Delayed Entropy Coupled Boundary Condition is then derived in order to account for this interaction in the framework of a Helmholtz solver where the baseline flow is assumed at rest. When fed with appropriate transfer functions to model the entropy generation and convection from the flame to the exit, the Helmholtz solver proves able to predict the presence of an unstable mode around 350 Hz, in agreement with both the LES and the experiments. This finding supports the idea that the instability observed in the combustor is indeed driven by the entropy/acoustic coupling.

Dynamic mode decomposition analysis of plasma aeroelastic control of airfoils in cascade

2020 ◽  
Vol 94 ◽  
pp. 102901 ◽  
Author(s):  
P. Neumann ◽  
V.B.C. de Almeida ◽  
V. Motta ◽  
L. Malzacher ◽  
D. Peitsch ◽  
...  
Keyword(s):  
Decomposition Analysis ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Mode Decomposition
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