High resolution imaging of flameless and distributed turbulent combustion

Duwig, Christophe; Li, Bo; Li, Zhongshan; Aldén, Marcus

doi:10.1016/j.combustflame.2011.06.018

Cited by 81 publications

(66 citation statements)

References 22 publications

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“…Intense research on mild combustion has been carried out in the last two decades, encompassing both experimental (Dally et al, 2004;Weber et al, 2005;Parente et al, 2008;Szegö et al, 2009;Veríssimo et al, 2011;Oldenhof et al, 2011;Arghode et al, 2012;Duwig et al, 2012;Sidey and Mastorakos, 2014) and computational (Coelho and Peters, 2001;Orsino et al, 2001;Mancini et al, 2007;Duwig et al, 2007;Galletti et al, 2007;Danon et al, 2010;Liu and Zheng, 2013) investigations. In order to improve the understanding of the underlying physics, a hot jet in a diluted co-flow, which emulates the mild combustion regime, has also been investigated by several authors (Christo and Dally, 2005;Frassoldati et al, 2010;De et al, 2011;Mardani et al, 2011;Aminian et al, 2012).…”

Section: Combustion Science and Technologymentioning

confidence: 99%

Experimental and Numerical Investigation of the Influence of the Air Preheating Temperature on the Performance of a Small-Scale Mild Combustor

Veríssimo

Rocha

Coelho

et al. 2015

Combustion Science and Technology

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Section: Combustion Science and Technologymentioning

confidence: 99%

Experimental and Numerical Investigation of the Influence of the Air Preheating Temperature on the Performance of a Small-Scale Mild Combustor

Veríssimo

Rocha

Coelho

et al. 2015

Combustion Science and Technology

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“…The reaction zone thickness is defined to be the width of the formaldehyde-OH overlap layer, based on its full-width at 85% maximum; 85% was selected because lower values were lost when noise reduction filtering was applied. Previous studies [20][21][22][23][24][25][26][27][30][31][32][33][34] also have used the overlap of OH and formaldehyde or HCO to define the reaction layer. The preheat zone thickness is defined as the distance between the 20% point on the formaldehyde curve (T = 400 K) and the edge of the formaldehyde x OH curve.…”

Section: American Institute Of Aeronautics and Astronauticsmentioning

confidence: 97%

“…Thus a flame could become shredded before it is broadened. Shredding of flamelets allows reactants to mix with hot products, which can create distributed reactions 13,14,[20][21][22][23] .…”

Section: Somementioning

confidence: 99%

Experimental Investigation of Premixed Turbulent Combustion in High Reynolds Number Regimes using PLIF

Temme

Skiba

Wabel

et al. 2014

52nd Aerospace Sciences Meeting

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Premixed turbulent flame structures are imaged with simultaneous formaldehyde and OH PLIF. A new piloted burner was designed to achieve high turbulent Reynolds numbers (Re t ) up to 68,000 and low Damköhler numbers (Da t ). Primary reaction zones are identified by the overlap of the OH and formaldehyde signals and preheat zones of low temperature secondary reactions are identified from the formaldehyde signal. At low Re t of 600, the primary reaction zones are continuous and products do not mix with reactants. This results in thin preheat layers and relatively thin flamelets. As Re t increases, the primary reaction zones become shredded and disconnected. This allows mixing of the hot products with the reactants and broadens the preheat/secondary reaction zones. Additionally, the reaction layers are typically 4-5 times thicker than those in a laminar flamelet. Interestingly, as Re t increases further, the thickness of the reaction layers only increases slowly, but the total area of reaction regions grows rapidly. I. IntroductionHERE are several gaps in our fundamental understanding of the physics of premixed turbulent flames. Many previous studies 1-10 have been conducted at large turbulence intensities (u'/S L ) but at small values of integral scale , which usually is normalized by laminar flame thickness ). The r.m.s. velocity fluctuation is u' and S L is the unstretched laminar burning velocity. However in many realistic devices it is the product of u' and that is large. Therefore the present work focuses on the regime of large turbulence Reynolds numbers (Re t ) and small Damköhler numbers (Da t ) where:

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“…A common approach to perform Rayleigh measurements is to use a 90 angle collection configuration. 71 In case of limited optical access, a picosecond lidar (light detection and ranging) concept can be adapted where the back-scattered Rayleigh signal [72][73][74] is collected. The short pulse duration is employed in picosecond lidar to spatially resolve the temperature distribution.…”

Section: Spontaneous Molecular Scattering Techniquesmentioning

confidence: 99%

Advanced Laser-Based Techniques for Gas-Phase Diagnostics in Combustion and Aerospace Engineering

Ehn

Zhu

et al. 2017

Appl Spectrosc

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Gaining information of species, temperature, and velocity distributions in turbulent combustion and high-speed reactive flows is challenging, particularly for conducting measurements without influencing the experimental object itself. The use of optical and spectroscopic techniques, and in particular laser-based diagnostics, has shown outstanding abilities for performing non-intrusive in situ diagnostics. The development of instrumentation, such as robust lasers with high pulse energy, ultra-short pulse duration, and high repetition rate along with digitized cameras exhibiting high sensitivity, large dynamic range, and frame rates on the order of MHz, has opened up for temporally and spatially resolved volumetric measurements of extreme dynamics and complexities. The aim of this article is to present selected important laser-based techniques for gas-phase diagnostics focusing on their applications in combustion and aerospace engineering. Applicable laser-based techniques for investigations of turbulent flows and combustion such as planar laser-induced fluorescence, Raman and Rayleigh scattering, coherent anti-Stokes Raman scattering, laser-induced grating scattering, particle image velocimetry, laser Doppler anemometry, and tomographic imaging are reviewed and described with some background physics. In addition, demands on instrumentation are further discussed to give insight in the possibilities that are offered by laser flow diagnostics.

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High resolution imaging of flameless and distributed turbulent combustion

Cited by 81 publications

References 22 publications

Experimental and Numerical Investigation of the Influence of the Air Preheating Temperature on the Performance of a Small-Scale Mild Combustor

Experimental and Numerical Investigation of the Influence of the Air Preheating Temperature on the Performance of a Small-Scale Mild Combustor

Experimental Investigation of Premixed Turbulent Combustion in High Reynolds Number Regimes using PLIF

Advanced Laser-Based Techniques for Gas-Phase Diagnostics in Combustion and Aerospace Engineering

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