Numerical Investigation of Combustion Instability in a V-Gutter Stabilized Combustor

Sundaram, S.; Babu, V.

doi:10.1115/1.4025261

Cited by 6 publications

(4 citation statements)

References 25 publications

(38 reference statements)

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“…POD was first applied to turbulent flows by Lumley and coworkers [30] but to date has been used to understand vorticity in swirl-stabilized combustors [31][32][33][34], periodic fluctuations in turbulent shear layers [35,36], vibrational modes in forced resonance systems [37], and fluctuations in V-gutter combustion wakes [38,39]. POD has also recently been used as a means to compare the large outputs from numerical simulations of large eddy simulations to experimental chemiluminescence data for validation purposes [40,41].…”

Section: Methodsmentioning

confidence: 99%

Multi-angular Flame Measurements and Analysis in a Supersonic Wind Tunnel Using Fiber-Based Endoscopes

Wickersham

et al. 2015

Journal of Engineering for Gas Turbines and Power

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This paper reports new measurements and analysis made in the Research Cell 19 supersonic wind-tunnel facility housed at the Air Force Research Laboratory. The measurements include planar chemiluminescence from multiple angular positions obtained using fiber-based endoscopes (FBEs) and the accompanying velocity fields obtained using particle image velocimetry (PIV). The measurements capture the flame dynamics from different angles (e.g., the top and both sides) simultaneously. The analysis of such data by proper orthogonal decomposition (POD) will also be reported. Nonintrusive and full-field imaging measurements provide a wealth of information for model validation and design optimization of propulsion systems. However, it is challenging to obtain such measurements due to various implementation difficulties such as optical access, thermal management, and equipment cost. This work therefore explores the application of the FBEs for nonintrusive imaging measurements in the supersonic propulsion systems. The FBEs used in this work are demonstrated to overcome many of the practical difficulties and significantly facilitate the measurements. The FBEs are bendable and have relatively small footprints (compared to high-speed cameras), which facilitates line-of-sight optical access. Also, the FBEs can tolerate higher temperatures than high-speed cameras, ameliorating the thermal management issues. Finally, the FBEs, after customization, can enable the capture of multiple images (e.g., images of the flow fields at multi-angles) onto the same camera chip, greatly reducing the equipment cost of the measurements. The multi-angle data sets, enabled by the FBEs as discussed above, were analyzed by POD to extract the dominating flame modes when examined from various angular positions. Similar analysis was performed on the accompanying PIV data to examine the corresponding modes of the flow fields. The POD analysis provides a quantitative measure of the dominating spatial modes of the flame and flow structures, and is an effective mathematical tool to extract key physics from large data sets as the high-speed measurements collected in this study. However, the past POD analysis has been limited to data obtained from one orientation only. The availability of data at multiple angles in this study is expected to provide further insights into the flame and flow structures in high-speed propulsion systems.

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Section: Methodsmentioning

confidence: 99%

Multi-angular Flame Measurements and Analysis in a Supersonic Wind Tunnel Using Fiber-Based Endoscopes

Wickersham

et al. 2015

Journal of Engineering for Gas Turbines and Power

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“…The analysis road map is based on Rayleigh criteria [3]. If the phase between the pressure fluctuation and the heat release rate (HRR) fluctuation is less than π/4, and the integral of their product's volume is larger than the damping of the system, the thermoacoustic issue occurs [4].…”

Section: Introductionmentioning

confidence: 99%

Analysis of V-Gutter Reacting Flow Dynamics Using Proper Orthogonal and Dynamic Mode Decompositions

2020

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The current work is focused on investigating the potential of data-driven post-processing techniques, including proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) for flame dynamics. Large-eddy simulation (LES) of a V-gutter premixed flame was performed with two Reynolds numbers. The flame transfer function (FTF) was calculated. The POD and DMD were used for the analysis of the flame structures, wake shedding frequency, etc. The results acquired by different methods were also compared. The FTF results indicate that the flames have proportional, inertial, and delay components. The POD method could capture the shedding wake motion and shear layer motion. The excited DMD modes corresponded to the shear layer flames’ swing and convect motions in certain directions. Both POD and DMD could help to identify the wake shedding frequency. However, this large-scale flame oscillation is not presented in the FTF results. The negative growth rates of the decomposed mode confirm that the shear layer stabilized flame was more stable than the flame possessing a wake instability. The corresponding combustor design could be guided by the above results.

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Section: Introductionmentioning

confidence: 99%

“…A 3D compressible and unsteady reacting turbulent flow has been investigated using large eddy simulation (LES) by Sundaram and Babu. 17 The time history of the pressure at some locations is applied to compute the Be´nard-von Ka´rma´n vortex shedding frequency. Also, Kim et al 18 employed LES approach to investigate the effects of the presence of channel walls on the characteristics of the flow field behind a square cylinder at Re ¼ 3000 and blockage ratio of 20%.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of cold flow over regular and wavy V-gutters

Mollaei¹,

Ghassemi

2019

Proceedings of the Institution of Mechanical Engineers, Part G:

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In this paper, the numerical study of cold flow over two types of regular and wavy V-gutter flame holders has been presented. The edges of the V-gutter, which are smooth in the regular case, are shaped in a sinusoidal form with different phase angles on upper and lower edges. The three-dimensional numerical analysis has been performed using the finite volume method and the renormalization group k–ɛ model has been used for turbulence modeling. The results were compared and validated by an existing experimental work based on the particle image velocimetry method. This study provided the fluid flow structure behind the V-gutter, the dimensions of the recirculation region, the behavior of vortex shedding phenomenon, and the static pressure distribution in the wake area. According to the results, the recirculation length for the sinusoidal case with 90 ° of the phase difference is the largest compared with the other cases, which increases the mass flow rate of the fresh unburnt mixture into the recirculation region and improves flame stability. The results also show that the 90 ° wavy V-gutter case has the lowest pressure drop in the wake region, which reduces the drag coefficient against the main flow. The values of the Strouhal number are approximately the same and equal to 0.27 for both cases (the regular and the 90 ° cases). Therefore, it is concluded that the 90 ° wavy V-gutter shows better performance than the regular V-gutter in flame stabilization.

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Numerical Investigation of Combustion Instability in a V-Gutter Stabilized Combustor

Cited by 6 publications

References 25 publications

Multi-angular Flame Measurements and Analysis in a Supersonic Wind Tunnel Using Fiber-Based Endoscopes

Multi-angular Flame Measurements and Analysis in a Supersonic Wind Tunnel Using Fiber-Based Endoscopes

Analysis of V-Gutter Reacting Flow Dynamics Using Proper Orthogonal and Dynamic Mode Decompositions

Numerical investigation of cold flow over regular and wavy V-gutters

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