Investigation of Flame Structure and Combustion Dynamics using CH2O PLIF and High-Speed CH* Chemiluminescence in a Premixed Dual-Mode Scramjet Combustor

2016 ◽  
Author(s):  
Patton Allison ◽  
Kraig Frederickson ◽  
Justin W. Kirik ◽  
Robert D. Rockwell ◽  
Walter R. Lempert ◽  
...  
Keyword(s):  
High Speed ◽  
Flame Structure ◽  
Dual Mode ◽  
Combustion Dynamics ◽  
Scramjet Combustor

Dynamics and Stability Limits of Syngas Combustion in a Swirl-Stabilized Combustor

2008 ◽  
Author(s):  
Raymond L. Speth ◽  
H. Murat Altay ◽  
Duane E. Hudgins ◽  
Ahmed F. Ghoniem
Keyword(s):  
High Speed ◽  
Equivalence Ratio ◽  
Fluid Dynamic ◽  
Flame Structure ◽  
Low Frequency ◽  
Operating Conditions ◽  
Video Data ◽  
Combustion Dynamics ◽  
Lean Blowout ◽  
Operating Modes

The combustion dynamics, stability bands and flame structure of syngas flames under different operating conditions are investigated in an atmospheric pressure swirl-stabilized combustor. Pressure measurements and high-speed video data are used to distinguish several operating modes. Increasing the equivalence ratio makes the flame more compact, and in general increases the overall sound pressure level. Very close to the lean blowout limit, a long stable flame anchored to the inner recirculation zone is observed. At higher equivalence ratios, a low frequency, low amplitude pulsing mode associated with the fluid dynamic instabilities of axial swirling flows is present. Further increasing the equivalence ratio produces unstable flames oscillating at frequencies coupled with the acoustic eigenmodes. Additionally, a second unstable mode, coupled with a lower eigen-mode of the system, is observed for flames with CO concentration higher than 50%. As the amount of hydrogen in the fuel is increased, the lean flammability limit is extended and transitions between operating regimes move to lower equivalence ratios.

scholarly journals Flame Structure and Dynamics in a Premixed Dual-Mode Scramjet Combustor from Fluorescence Imaging

2019 ◽  
Vol 35 (3) ◽  
pp. 552-564 ◽  
Author(s):  
Patton M. Allison ◽  
Kraig Frederickson ◽  
Justin W. Kirik ◽  
Robert D. Rockwell ◽  
Christopher P. Goyne ◽  
...  
Keyword(s):  
Fluorescence Imaging ◽  
Flame Structure ◽  
Dual Mode ◽  
Structure And Dynamics ◽  
Scramjet Combustor

Effect of Chemical Composition of Syngas on Combustion Dynamics Inside Bluff-Body Type Turbulent Syngas Combustor

2018 ◽  
Author(s):  
Nikhil Ashokbhai Baraiya ◽  
Satynarayanan R. Chakravarthy
Keyword(s):  
Chemical Composition ◽  
High Speed ◽  
Bluff Body ◽  
Dynamic Pressure ◽  
Flame Structure ◽  
Acoustic Behavior ◽  
Body Type ◽  
Combustion Dynamics ◽  
Co2 Intensity ◽  
Dynamic Pressure Measurement

In the present work, the chemical composition of syngas is changed by varying the H2/CO ratio, to map the change in the acoustic behavior of a bluff-body combustor. It was observed that with increase in hydrogen concentration in the syngas mixture, the frequency shifts to higher modes and the flame structures changes. The flame oscillations are mapped by means of simultaneous high-speed OH* and CO2* chemiluminescence imaging along with dynamic pressure measurement. The plots of spatial distribution of OH* and CO2* intensity are used to understand change in flame structure with change in chemical composition and also to help in understanding the kinetics affecting acoustic behavior of the flame. The change in flow structures with change in chemical composition of fuel is studied by simultaneous high-speed PIV, OH* chemiluminescence and dynamic pressure measurements.

Hybrid Large Eddy Simulation/Reynolds-Averaged Navier–Stokes Analysis of a Premixed Ethylene-Fueled Dual-Mode Scramjet Combustor

AIAA Journal ◽  
2021 ◽  
pp. 1-17
Author(s):  
Tanner B. Nielsen ◽  
Jack R. Edwards ◽  
Harsha K. Chelliah ◽  
Damien Lieber ◽  
Clayton Geipel ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Navier Stokes ◽  
Dual Mode ◽  
Eddy Simulation ◽  
Scramjet Combustor ◽  
Large Eddy ◽  
Reynolds Averaged Navier Stokes

Experimental Investigation of Combustion Dynamics in a Turbulent Syngas Combustor

2017 ◽  
Author(s):  
Nikhil Ashokbhai Baraiya ◽  
Baladandayuthapani Nagarajan ◽  
Satynarayanan R. Chakravarthy
Keyword(s):  
High Speed ◽  
Equivalence Ratio ◽  
Bluff Body ◽  
Dynamic Pressure ◽  
Fuel Mixture ◽  
High Amplitude ◽  
Acoustic Oscillations ◽  
Combustion Dynamics ◽  
Dynamic Pressure Measurement ◽  
Body Location

In the present work, the proportion of carbon monoxide to hydrogen is widely varied to simulate different compositions of synthesis gas and the potential of the fuel mixture to excite combustion oscillations in a laboratory-scale turbulent bluff body combustor is investigated. The effect of parameters such as the bluff body location and equivalence ratio on the self-excited acoustic oscillations of the combustor is studied. The flame oscillations are mapped by means of simultaneous high-speed CH* and OH* chemiluminescence imaging along with dynamic pressure measurement. Mode shifts are observed as the bluff body location or the air flow Reynolds number/overall equivalence ratio are varied for different fuel compositions. It is observed that the fuel mixtures that are hydrogen-rich excite high amplitude pressure oscillations as compared to other fuel composition cases. Higher H2 content in the mixture is also capable of exciting significantly higher natural acoustic modes of the combustor so long as CO is present, but not without the latter. The interchangeability factor Wobbe Index is not entirely sufficient to understand the unsteady flame response to the chemical composition.

scholarly journals Dual Mode High Speed Uncooled Short Wave Infrared Camera Based on FPGA

2021 ◽  
Vol 1952 (3) ◽  
pp. 032042
Author(s):  
Qing Liu ◽  
Huawei Wang ◽  
He Bian ◽  
Hua Wang
Keyword(s):  
High Speed ◽  
Infrared Camera ◽  
Short Wave ◽  
Dual Mode ◽  
Short Wave Infrared

Observation on Solid Propellant Ignition Using High Speed Camera: The Effect of Hot Wire Position on the Combustion Flame Contour

2014 ◽  
Vol 71 (2) ◽  
Author(s):  
Wan Khairuddin Wan Ali ◽  
Ang Kiang Long ◽  
Mohammad Nazri Mohd. Jaafar
Keyword(s):  
Solid Propellant ◽  
High Speed ◽  
Flame Structure ◽  
Combustion Process ◽  
Ignition Process ◽  
High Speed Camera ◽  
Hot Wire ◽  
Composite Propellant ◽  
Burning Behavior ◽  
Insight Into

This paper reports on the discovery of unique flame structure of a composite propellant sample under hot wire ignition. The entire combustion process at atmospheric pressure condition was recorded using a high speed camera. Three hot wire orientations were chosen in this experiment for examining their effects on the propellant burning behavior. The results show that the wire orientations are crucial in propellant combustion process, as different flame patterns were observed when the hot wire orientation was altered. This paper provides an important insight into this specific ignition process that can be useful for researchers in the aerospace industry for better design and more realistic simulation results in ignition control.

Emission Measurements and CH* Chemiluminescence of a Staged Combustion Rig for Stationary Gas Turbine Applications

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
Warren G. Lamont ◽  
Mario Roa ◽  
Scott E. Meyer ◽  
Robert P. Lucht
Keyword(s):  
Combustion Zone ◽  
High Speed ◽  
Equivalence Ratio ◽  
Flame Structure ◽  
Exhaust Gas ◽  
Staged Combustion ◽  
High Pressure Turbine ◽  
Transverse Jet ◽  
Sampling Probe ◽  
Good Agreement

An optically accessible combustion rig was constructed to study the combustion characteristics of a reactive jet in a vitiated crossflow. The rig features two staged combustion zones. The main combustion zone is a swirl stabilized dump combustor. The second combustion zone, which is axially downstream from the main combustion zone, is formed by a transverse jet injecting either fuel or a premixed fuel/air mixture into the vitiated stream. The rig was designed to investigate the transverse jet conditions, equivalence ratio, and momentum ratios that produce low NOx and give an adequate temperature rise before the simulated high pressure turbine. A water-cooled sampling probe extracts exhaust gas downstream for emission measurements. As a baseline, the main combustion zone was fired without the transverse jet and the results compare closely to the work of previous researchers. The emission survey with the transverse jet found several conditions that show a benefit of staging compared to the baseline of firing only the main combustion zone. The flame structure from the transverse jet was captured using high speed CH* chemiluminescence, which shows the extent of the flame front and its penetration depth into the vitiated stream. The chemiluminescence images were averaged and compared to the Holdeman correlation, which showed good agreement for injection with fuel only but poorer agreement when premixed.

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