Laser Raman scattering in fuel-rich flames: background levels at different excitation wavelengths

Meier, Wolfgang; Keck, O.

doi:10.1088/0957-0233/13/5/312

Cited by 41 publications

(13 citation statements)

References 39 publications

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“…One important conclusion was that for their experimental conditions 355 nm excitation proved to be a better candidate wavelength than previously thought. Meier and Keck [13] and Rabenstein and Leipertz [14] investigated premixed sooting and non-sooting C 2 H 4 /air and CH 4 /air flames, respectively. In Meier and Keck's comparative study the signal-to-background ratio of Raman measurements was investigated for pulsed laser radiation at 532, 489, 355, and 266 nm.…”

Section: Introductionmentioning

confidence: 99%

Raman/Rayleigh scattering and CO-LIF measurements in laminar and turbulent jet flames of dimethyl ether

Fuest

Barlow

Chen

et al. 2012

Combustion and Flame

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To reduce the impact of combustion of fossil fuels on air quality and climate change, dimethyl ether (DME) is a promising alternative diesel fuel candidate. Technical combustion processes, including formation of pollutants, are influenced by turbulence-chemistry interaction. Therefore, accurate prediction by computational combustion models of combustion systems burning DME must account for multiple scalars and scalar gradients. The testing of such models requires detailed experiments. Here a study is presented on the feasibility of simultaneous species and temperature measurements in turbulent dimethyl ether flames, using line-imaged Raman/Rayleigh scattering of the major species H 2 , O 2 , N 2 , CO, CO 2 , H 2 O, C 2 H 6 O and laser induced fluorescence of CO. The measurement system and data evaluation methods developed to investigate methane-air flames are extended to address dimethyl ether flames. The Raman signal intensity and spectral shape of the Raman scattering from dimethyl ether over a range of temperatures are presented, based on measurements in electrically heated flows and laminar jet flames. These data are used to develop an iterative method for data evaluation that allows determination of indispensable crosstalk correction terms for the concentration measurements of O 2 and CO 2. Issues of fluorescence interferences, mainly from C 2 radicals on the fuel-rich side of the reaction zone, and their corrections are discussed. Laminar flame calculations are used to investigate the role of the intermediate species (CH 4 , CH 2 O, C 2 H 4 , C 2 H 2 , C 2 H 6 , CH 3) in the reaction zone. In particular, their effect on the mixture fraction calculation and its relationship to the experimentally determined mixture fraction is examined. The impact of the intermediate species on deviations in concentration and temperature profiles due to species-specific Raman-and Rayleigh scattering cross-sections is demonstrated. Finally, species concentrations and temperature profiles from measurements in a turbulent piloted jet flame of dimethyl ether are shown.

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Section: Introductionmentioning

confidence: 99%

Raman/Rayleigh scattering and CO-LIF measurements in laminar and turbulent jet flames of dimethyl ether

Fuest

Barlow

Chen

et al. 2012

Combustion and Flame

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“…This crosstalk impacts all Raman channels and is generally found in rich hydrocarbon flames, e.g. [22]. Mostly, it starts at the fuel-rich side of the flame at temperatures between 1000 K and 1200 K. The crosstalk both appears at lower temperatures and increases in magnitude for higher fuel/air ratios, peaks between 1600-1800 K, and decreases significantly or even disappears before reaching the point of maximum temperature in the flame.…”

Section: Raman Scattering Of Acetylenementioning

confidence: 83%

Towards quantitative concentration measurement of acetylene in rich hydrocarbon flames using 1D Raman/Rayleigh scattering

Fuest

Dreizler

Sutton

2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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This work presents the extension of the established detection of seven major species in 1D Raman/Rayleigh measurements to incorporate acetylene as an eighth species. Acetylene is an important soot precursor which is generated in hydrocarbon flames as an intermediate species following decomposition. It occurs over a broad temperature range in the flame and has been identified as a potentially detectable species in 1D Raman/Rayleigh measurements. In this paper, we discuss the Raman spectral signature of acetylene, its temperature-dependence, calibration points, and the interference with other Raman-active species, C2 and broadband interferences, all of which are essential to quantify for accurate data processing. In this regard, Raman measurements in laminar and turbulent flames of dimethyl ether were aquired. The data was spectrally analyzed, and, in conjunction with laminar flame calculations, the necessary calibration points were derived to place the acetylene signals on an absolute scale. Finally, detection limits of acetylene, signal-to-noise, and signal-to-interference ratios in laminar and turbulent flames are discussed.

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“…in mixture formation processes [8][9][10][11][12] and flames. [13][14][15][16] In spite of being a challenging technique because of the weak signal, linear Raman spectroscopy seems to be perfectly suited for monitoring an anesthesia procedure. [17,18] Additionally there is no need for a sample preparation, which enables an access to in situ measurements inside the breathing circuit.…”

Section: Introductionmentioning

confidence: 99%

Demonstration of a signal enhanced fast Raman sensor for multi‐species gas analyses at a low pressure range for anesthesia monitoring

Schlüter

Krischke

Popovska-Leipertz³

et al. 2015

J Raman Spectroscopy

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The spontaneous Raman scattering technique is an excellent tool for a quantitative analysis of multi-species gas mixtures. It is a noninvasive optical method for species identification and gas phase concentration measurement of Raman active molecules, since the intensity of the molecule specific Raman signal is linearly dependent on the concentration. Applying a continuous wave (cw) laser it typically takes a few seconds to capture a gas phase Raman spectrum at room temperature. Nevertheless in contrast to these advantages the weak Raman signal intensity is a major drawback. Thus, it is still challenging to detect gas phase Raman spectra in a low-pressure regime with a temporal resolution of only a few 100 ms. In the presented study a fully functional gas phase Raman system for measurements in the low-pressure regime (p ≥ 980 hPa (absolute)) is presented; it overcomes the drawback of the weak Raman effect by using a multipass cavity to enhance the Raman signal. The signal amplification of a retroreflecting cavity is experimentally compared to a near-confocal cavity. A description of this sensor setup as well as of the calibration procedure, which also allows the quantification of condensable gases, is presented. Moreover the functionality of the sensor system is demonstrated in a measurement campaign at an anesthesia simulator under clinical relevant conditions and in comparison to a conventional gas monitor.

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Laser Raman scattering in fuel-rich flames: background levels at different excitation wavelengths

Cited by 41 publications

References 39 publications

Raman/Rayleigh scattering and CO-LIF measurements in laminar and turbulent jet flames of dimethyl ether

Raman/Rayleigh scattering and CO-LIF measurements in laminar and turbulent jet flames of dimethyl ether

Towards quantitative concentration measurement of acetylene in rich hydrocarbon flames using 1D Raman/Rayleigh scattering

Demonstration of a signal enhanced fast Raman sensor for multi‐species gas analyses at a low pressure range for anesthesia monitoring

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