Measurement of the conditioned turbulence and temperature field of a premixed Bunsen burner by planar laser Rayleigh scattering and stereo particle image velocimetry

Pfadler, Sebastian; Löffler, M.; Dinkelacker, Friedrich; Leipertz, Alfred

doi:10.1007/s00348-005-0980-x

Cited by 32 publications

(11 citation statements)

References 10 publications

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“…6 Shepherd and Cheng 2001;Haq et al 2002;Gülder and Smallwood 2007;Petersson et al 2007;Kiefer et al 2008). This technique has also been applied to flows seeded with either oil droplets (Shepherd et al 1992;Veynante et al 1994;Shepherd 1996) or solid particles (Pfadler et al 2005;Pfadler et al 2007) where planar imaging is used to determine the reactant region and hence the flame-front. The threshold value can be set at a constant value or be calculated by generating a histogram of the image pixel intensities.…”

Section: Filter Comparisonmentioning

confidence: 98%

Local curvature measurements of a lean, partially premixed swirl-stabilised flame

2011

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A swirl-stabilised, lean, partially premixed combustor operating at atmospheric conditions has been used to investigate the local curvature distributions in lifted, stable and thermoacoustically oscillating CH 4 -air partially premixed flames for bulk cold-flow Reynolds numbers of 15,000 and 23,000. Single-shot OH planar laser-induced fluorescence has been used to capture instantaneous images of these three different flame types. Use of binary thresholding to identify the reactant and product regions in the OH planar laser-induced fluorescence images, in order to extract accurate flame-front locations, is shown to be unsatisfactory for the examined flames. The Canny-Deriche edge detection filter has also been examined and is seen to still leave an unacceptable quantity of artificial flame-fronts. A novel approach has been developed for image analysis where a combination of a non-linear diffusion filter, Sobel gradient and thresholdbased curve elimination routines have been used to extract traces of the flame-front to obtain local curvature distributions. A visual comparison of the effectiveness of flamefront identification is made between the novel approach, the threshold binarisation filter and the Canny-Deriche filter. The novel approach appears to most accurately identify the flame-fronts. Example histograms of the curvature for six flame conditions and of the total image area are presented and are found to have a broader range of local flame curvatures for increasing bulk Reynolds numbers. Significantly positive values of mean curvature and marginally positive values of skewness of the histogram have been measured for one lifted flame case, but this is generally accounted for by the effect of flame brush curvature. The mean local flame-front curvature reduces with increasing axial distance from the burner exit plane for all flame types. These changes are more pronounced in the lifted flames but are marginal for the thermoacoustically oscillating flames. It is concluded that additional fuel mixture fraction and velocimetry studies are required to examine whether processes such as the degree of partial-premixedness close to the burner exit plane, the velocity field and the turbulence field have a strong correlation with the curvature characteristics of the investigated flames.

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Section: Filter Comparisonmentioning

confidence: 98%

Local curvature measurements of a lean, partially premixed swirl-stabilised flame

2011

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“…The technique observes the distinct step in particle number density due to the dilatation of the seeded gas as it passes through the flame front [38,39]. With the help of an adaptive histogram-based intensity-threshold detection algorithm, flame front contours could be extracted from the particle number density gradient in the PIV particle raw images.…”

Section: Conditioned Particle Image Velocimetrymentioning

confidence: 99%

The structure of turbulent flames in fractal- and regular-grid-generated turbulence

Sponfeldner

Soulopoulos

Beyrau

et al. 2015

Combustion and Flame

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“…The residence probability of burnt gas at this location was measured to be 41%, which is comparable to the earlier Rayleigh-scattering temperature measurements. 16 …”

Section: Resultsmentioning

confidence: 99%

“…The diameter of the burner outlet was 48 mm. More details of this burner can be found in Pfadler et al, 16 in which the burner was used for planar temperature measurements by Rayleigh scattering. The burner was adjusted for a fuel/air ratio of D 1 with a mixture flow of ¾120 slm of methane and air.…”

Section: Methodsmentioning

confidence: 99%

Identification of spatial averaging effects in vibrational CARS spectra

Seeger

Weikl

Beyrau

et al. 2006

J Raman Spectroscopy

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Accurate temperature measurements with the coherent anti-Stokes Raman scattering (CARS) technique are difficult to perform when temperature gradients occur within the measurement volume. Very often it is even difficult or time consuming to identify the influence of spatial averaging on the measurement. To solve this problem, a weighting procedure based on a combination of least-sum-of-squared-differences-fits (LSF) using different weighting factors was developed and tested by using experimental data, measured in a laminar and in a turbulent premixed methane/air flame. With this evaluation procedure it was possible to identify spatially averaged CARS spectra in order to sort them out avoiding the problems arising from the nonlinear nature of the CARS process. Using this new fitting approach, the expected bimodal temperature distribution near the flame front of the turbulent premixed flame can be confirmed.

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Measurement of the conditioned turbulence and temperature field of a premixed Bunsen burner by planar laser Rayleigh scattering and stereo particle image velocimetry

Cited by 32 publications

References 10 publications

Local curvature measurements of a lean, partially premixed swirl-stabilised flame

Local curvature measurements of a lean, partially premixed swirl-stabilised flame

The structure of turbulent flames in fractal- and regular-grid-generated turbulence

Identification of spatial averaging effects in vibrational CARS spectra

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