LES of oxy-fuel jet flames using the Eulerian Stochastic Fields method with differential diffusion

2020 ◽  
Author(s):  
Maximilian Hansinger ◽  
Michael Pfitzner ◽  
Vladimir Sabelnikov
Keyword(s):  
Jet Flames ◽  
Differential Diffusion ◽  
Stochastic Fields ◽  
Fuel Jet

Assessment of Stabilization Mechanisms of Confined, Turbulent, Lifted Jet Flames: Effects of Ambient Coflow

2013 ◽  
Author(s):  
Andrew R. Hutchins ◽  
James D. Kribs ◽  
Richard D. Muncey ◽  
Kevin M. Lyons
Keyword(s):  
Turbulent Mixing ◽  
Leading Edge ◽  
Ambient Air ◽  
Turbulent Jet ◽  
Fuel Flow Rate ◽  
Jet Flames ◽  
Combustion Chemistry ◽  
Intermittent Behavior ◽  
Fuel Flow ◽  
Fuel Jet

The aim of this investigation is to determine the effects of confinement on the stabilization of turbulent, lifted methane (CH4) jet flames. A confinement cylinder (stainless steel) separates the coflow from the ambient air and restricts excess room air from being entrained into the combustion chamber, and thus produces varying stabilization patterns. The experiments were executed using fully confined, semi-confined, and unconfined conditions, as well as by varying fuel flow rate and coflow velocity (ambient air flowing in the same direction as the fuel jet). Methane flames experience liftoff and blowout at well-known conditions for unconfined jets, however, it was determined that with semi-confined conditions the flame does not experience blowout. Instead of the conventional unconfined stabilization patterns, an intense, intermittent behavior of the flame was observed. This sporadic behavior of the flame, while under semi-confinement, was determined to be a result from the restricted oxidizer access as well as the asymmetrical boundary layer that forms due to the viewing window. While under full confinement the flame behaved in a similar method as while under no confinement (full ambient air access). The stable nature of the flame while fully confined lacked the expected change in leading edge fluctuations that normally occur in turbulent jet flames. These behaviors address the combustion chemistry (lack of oxygen), turbulent mixing, and heat release that combine to produce the observed phenomena.

Structure Analysis of the Stabilizing Region of Plane, Laminar Fuel-Jet. Flames.

1980 ◽  
Vol 22 (5-6) ◽  
pp. 211-216 ◽  
Author(s):  
TAKESHI KAWAMURA ◽  
KATSUO ASATO ◽  
TAMOTSU MAZAKI
Keyword(s):  
Structure Analysis ◽  
Jet Flames ◽  
Fuel Jet

scholarly journals On the structure of the near field of oxy-fuel jet flames using Raman/Rayleigh laser diagnostics

2012 ◽  
Vol 159 (11) ◽  
pp. 3342-3352 ◽  
Author(s):  
Alexis Sevault ◽  
Matthew Dunn ◽  
Robert S. Barlow ◽  
Mario Ditaranto
Keyword(s):  
Laser Diagnostics ◽  
Near Field ◽  
Jet Flames ◽  
Fuel Jet

Detailed investigation of NO mechanism in non-premixed oxy-fuel jet flames with CH4/H2 fuel blends

2018 ◽  
Vol 43 (17) ◽  
pp. 8534-8557 ◽  
Author(s):  
Xudong Jiang ◽  
Pengfei Li ◽  
Junjun Guo ◽  
Fan Hu ◽  
Feifei Wang ◽  
...  
Keyword(s):  
Jet Flames ◽  
Fuel Blends ◽  
Fuel Jet

scholarly journals A Combined Experimental and Numerical Study of Laminar and Turbulent Non-piloted Oxy-fuel Jet Flames Using a Direct Comparison of the Rayleigh Signal

2015 ◽  
Vol 97 (1) ◽  
pp. 231-262 ◽  
Author(s):  
Franziska Hunger ◽  
Meor F. Zulkifli ◽  
Benjamin A. O. Williams ◽  
Frank Beyrau ◽  
Christian Hasse
Keyword(s):  
Numerical Study ◽  
Jet Flames ◽  
Fuel Jet

scholarly journals Improvement of the Combustion Completeness of Hydrogen Jet Flames within a Mesoscale Tube under Zero Gravity

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4552
Author(s):  
Junjie Hong ◽  
Ming Zhao ◽  
Lei Liu ◽  
Qiuxiang Shi ◽  
Xi Xiao ◽  
...  
Keyword(s):  
Air Entrainment ◽  
Combustion Efficiency ◽  
Zero Gravity ◽  
Jet Flames ◽  
Entrainment Ratio ◽  
Convergent Nozzle ◽  
Air Supply ◽  
Fuel Jet ◽  
Inner Diameter ◽  
Micro Propulsion

Microjet hydrogen flames can be directly used as micro heat sources or can be applied in micro propulsion systems. In our previous study, under zero gravity and without an active air supply, the combustion completeness of hydrogen jet flames within a mesoscale tube with an inner diameter of 5 mm was very low. In this study, we were dedicated to improving the combustion efficiency by using a convergent nozzle (tilt angle was around 68°) instead of the previous straight one, and the exit diameter was 0.8 or 0.4 mm. The numerical results demonstrate that the maximum combustion efficiency in the case of d= 0.8 mm was only around 15%; however, the peak value for the case of d = 0.4 mm was around 36%. This happened because with d = 0.4 mm, the fuel jet velocity was around four times that of the d = 0.8 mm case. Hence, the negative pressure in the combustor of d = 0.4 mm decreased to a much lower level compared to that of d = 0.8 mm, which led to an enhancement of the air entrainment ratio. However, the highest combustion efficiency of d = 0.4 mm was still below 36%; therefore, a slightly larger tube or an even smaller nozzle exit diameter will be necessary for further improvements to the combustion efficiency.

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