scholarly journals Real-Gas-Flamelet-Model-Based Numerical Simulation and Combustion Instability Analysis of a GH2/LOX Rocket Combustor with Multiple Injectors

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 419
Author(s):  
Won-Sub Hwang ◽  
Bu-Kyeng Sung ◽  
Woojoo Han ◽  
Kang Y. Huh ◽  
Bok Jik Lee ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Combustion Instability ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Instability Analysis ◽  
Gas Combustion ◽  
Flamelet Model ◽  
Real Gas ◽  
Stable Combustion ◽  
Contour Plots

A large eddy simulation (LES) and combustion instability analysis are performed using OpenFOAM for the multiple shear-coaxial injector combustor DLR-BKD (in German Deutsches Zentrum für Luft–Brennkammer D, German Aerospace Center–Combustion Chamber D), which is a laboratory-scale combustor operating in a real-gas environment. The Redlich–Kwong–Peng–Robinson equation of state and steady-laminar flamelet model are adopted in the simulation to accurately capture the real-gas combustion effects. Moreover, the stable combustion under the LP4 condition is numerically analyzed, and the characteristics of the combustion flow field are investigated. In the numerical simulation of the combustion instability, the instability is generated by artificially superimposing the 1st transverse standing wave solution on the stable combustion solution. To decompose the combustion instability mode, the dynamic mode decomposition method is applied. Several combustion instability modes are qualitatively and quantitatively identified through contour plots and graphs, and the sustenance process of the limit cycle is investigated.

Combustion Instability Analysis of a Model Gas Turbine by Application of Dynamic Mode Decomposition

2019 ◽  
Vol 24 (1) ◽  
pp. 51-56 ◽  
Author(s):  
Yuangang Wang ◽  
Yuangang Wang ◽  
Chae Hoon Sohn ◽  
Jisu Yoon ◽  
Jinhyun Bae ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Combustion Instability ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Instability Analysis ◽  
Mode Decomposition

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.

Numerical Simulation of a GH2/LOX Rocket Combustor with Multiple Injectors Using Real Gas Flamelet Model

2019 ◽  
Author(s):  
Won-Sub Hwang ◽  
Woojoo Han ◽  
Kang Y. Huh ◽  
Seongyeol Goo ◽  
Bok Jik Lee ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flamelet Model ◽  
Real Gas

scholarly journals Numerical Simulation of a GH2/LOx Single Injector Combustor and the Effect of the Turbulent Schmidt Number

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6616
Author(s):  
Won-Sub Hwang ◽  
Woojoo Han ◽  
Kang Y. Huh ◽  
Juhoon Kim ◽  
Bok Jik Lee ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Schmidt Number ◽  
Liquid Oxygen ◽  
Temperature Profiles ◽  
Flamelet Model ◽  
Real Gas ◽  
The Real ◽  
Real Gas Effect ◽  
Turbulent Schmidt Number ◽  
Gas Effect

A large-eddy simulation (LES) of a gaseous hydrogen/liquid oxygen (GH2/LOX) single-injector rocket combustor is performed in this study. The Redlich–Kwong–Peng–Robinson (RK–PR) equation of state is used to simulate the real-gas effect under high-pressure conditions, and the steady laminar flamelet model (SLFM) is implemented to simulate fast chemistry, such as a H2/O2 reaction. From the numerical simulation, the characteristics of time-averaged flow and flame fields are obtained, and their relationship with the real-gas effect is investigated. It is possible to investigate unsteady flame features and the mixing mechanism of propellants in detail by examining multiple snapshots of the field contour. Another purpose of the study is to investigate the differences in flow and flame structures according to the variation in the turbulent Schmidt number. By comparing the simulation result with the natural OH* emission image and temperature profiles from experimental data, the appropriate range of the turbulent Schmidt number for the simulation is obtained. Furthermore, this paper suggests the usefulness and validity of the current research by quantitatively comparing (i.e., temperature profiles) numerical results with those of existing literature.

Detection and Analysis of Combustion Instability From Hi-Speed Flame Images Using Dynamic Mode Decomposition

2016 ◽  
Author(s):  
Sambuddha Ghosal ◽  
Vikram Ramanan ◽  
Soumalya Sarkar ◽  
Satyanarayanan R. Chakravarthy ◽  
Soumik Sarkar
Keyword(s):  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Structural Integrity ◽  
Combustion Instability ◽  
Complex Problem ◽  
Operating Conditions ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Flame Dynamics ◽  
Mode Decomposition

Flame dynamics and combustion instability is a complex problem involving different non-linearities. Combustion instability has several detrimental effects on flight-propulsion dynamics and structural integrity of gas turbines and any such spaces where combustion takes places internally, primarily in internal combustion engines. The description of coherent features of fluid flow in such cases is essential to our understanding of the flame dynamics and propagation processes. A method that is able to extract dynamic information from flow fields that are generated by a direct numerical simulation or visualized in a physical experiment (like in the case discussed in this paper) is Dynamic Mode Decomposition. This paper presents such a feature extraction and stability analysis of hi-speed combustion flames using Dynamic Mode Decomposition and it’s sparsity promoting variant. Extensive experimental data was collected in a swirl-stabilized dump combustor at various operating conditions (e.g. premixing level and flow velocity) for analysing the flame stability conditions.

scholarly journals Mixed acoustic–entropy combustion instabilities in gas turbines

2014 ◽  
Vol 749 ◽  
pp. 542-576 ◽  
Author(s):  
Emmanuel Motheau ◽  
Franck Nicoud ◽  
Thierry Poinsot
Keyword(s):  
Gas Turbines ◽  
Transfer Functions ◽  
Combustion Instability ◽  
Low Frequency ◽  
Acoustic Mode ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Reacting Flow ◽  
Exit Nozzle ◽  
Low Order

AbstractA combustion instability in a combustor terminated by a nozzle is analysed and modelled based on a low-order Helmholtz solver. A large eddy simulation (LES) of the corresponding turbulent, compressible and reacting flow is first performed and analysed based on dynamic mode decomposition (DMD). The mode with the highest amplitude shares the same frequency of oscillation as the experiment (approximately 320 Hz) and 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 700–750 Hz, it is postulated that the instability observed around 320 Hz stems from a mixed entropy–acoustic mode, where the acoustic generation associated with entropy spots being convected throughout the choked nozzle plays a key role. The DMD analysis allows one to extract from the LES results a low-order model that confirms that the mechanism of the low-frequency combustion instability indeed involves both acoustic and convected entropy waves. The delayed entropy coupled boundary condition (DECBC) (Motheau, Selle & Nicoud, J. Sound Vib., vol. 333, 2014, pp. 246–262) is implemented into a numerical 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/DECBC solver predicts the presence of an unstable mode around 320 Hz, in agreement with both LES and experiments.

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