Mapping of Luminescent Species in a Flame Front

Bertran, Celso Aparecido; Marques, Carla S. T.; Benvenutti, Leandro H.

doi:10.1080/00102209808952078

Cited by 13 publications

(11 citation statements)

References 12 publications

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“…Second, natural emission occurs near the region where they were generated, due to their small emission life time. 17 This can be used to relate the information obtained from flame emission spectra to the temperature or concentrations at a specific flame region. 5 Spontaneous or natural emission in flames is due to chemical reactions that produce chemical species in excited state.…”

Section: Introductionmentioning

confidence: 99%

Determination of liquefied petroleum flame temperatures using emission spectroscopy

Carinhana¹,

Barreta²,

Rocha³

et al. 2008

J. Braz. Chem. Soc.

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A espectroscopia de emissão foi utilizada na determinação da temperatura de chamas pré-misturadas de GLP. Investigou-se a emissão natural de radicais CH * em três diferentes condições de queima: razão estequiométrica de combustível/oxidante, excesso de combustível (chama rica) e excesso de oxidante (chama pobre). O valor médio obtido para a temperatura rotacional de CH * foi de 2845 70 K nas condições utilizadas nos experimentos. Esse valor não variou significativamente com os demais tipos de chama e é compatível com os cálculos de temperatura adiabática dos sistemas estudados. Essa temperatura também é concordante com resultados obtidos por via indireta, utilizando-se o método de linha reversa de sódio, que consiste em uma técnica bem estabelecida e independente da emissão natural. Temperaturas vibracionais de ca. 4600 K foram calculadas, indicando que o tempo de vida do CH * não é suficiente para que o equilíbrio entre os modos rotacionais e vibracionais seja estabelecido.Emission spectroscopy was used in the temperature determination of LPG (liquefied petroleum gas) premixed flames. Natural emission of CH * radicals was investigated in flames under three different burning conditions: fuel/oxydizer stoichiometric ratio, fuel excess (rich flame), and oxidizer excess (lean flame). An average value of 2845 70 K was obtained for CH * rotational temperature in the set up used in the experiments. This value did not show significant change with the type of flame analyzed and it is compatible with the calculated adiabatic flame temperatures of the investigated systems. This temperature value also agrees with that determined by an indirect measurement, using the sodium line reversal method, which is independent from the radical natural emission and well established in literature. Vibrational temperatures of ca. 4600 K were calculated, indicating that the CH * lifetime is insufficient for the establishment of an equilibrium state between the rotational and vibrational modes.

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Section: Introductionmentioning

confidence: 99%

Determination of liquefied petroleum flame temperatures using emission spectroscopy

Carinhana¹,

Barreta²,

Rocha³

et al. 2008

J. Braz. Chem. Soc.

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“…The bands of C 2 * radicals, known as the Swan system, are observed at 473.7, 516.2 and 563.5 nm, and are formed during the combustion of fuel-rich mixtures, as described in eqn (1). 34 In some cases there is an overlap near 563.5 nm influenced by sodium concentration in the samples doped with different solvents. As discussed above, samples doped with ethanol and thinner exhibit significantly higher concentration of sodium than other solvents.…”

Section: Resultsmentioning

confidence: 99%

A study of adulteration in gasoline samples using flame emission spectroscopy and chemometrics tools

Paulo

Mendes

Barros

et al. 2012

Analyst

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This work presents a low cost system based on Flame Emission Spectroscopy (FES) that enables the prediction of fuel adulteration. The spectral data acquired using FES were associated with chemometric tools--Partial Least Squares Discriminant Analysis (PLS-DA) and Partial Least Squares (PLS), aiming to predict gasoline adulterations with different solvents. The classification of the Brazilian adulterated gasoline samples with turpentine, thinner, kerosene, rubber solvent and ethanol was carried out through a PLS-DA model built using five latent variables (LV) with an accumulated variance of 100% on X and 76.78% on Y. The combination of these techniques provided the discrimination of distinct groups for each one of the studied adulterants. Subsequent to the classification, samples of adulterated gasoline with the same solvents with contents varying from 1 to 50% (v/v) were analyzed through FES and multivariate calibration curves were employed in order to predict the contents of the respective solvents. The results obtained by the combination of FES and PLS provided the determination of gasoline adulterants with small calibration and validation errors and also lower values than the ones reported in the literature using other spectroscopic techniques.

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“…To spatially resolve the temporal heat release characteristics in the reaction zone, chemiluminescence measurements of the CH radical were performed. The CH radicals have been shown to be representative of the ethanol flame front (Bertran et al, 1998) and CH intensity correlates well with the local heat release for this type of fuel. An intensified Princeton Instruments PI-Max 512 T-18 G=III CCD camera with a 512 Â 512 pixel resolution was utilized to acquire the images.…”

Section: Chemiluminescence Measurementsmentioning

confidence: 87%

“…An optical CH filter mounted on the photodiode allows the light at k ¼ 390 nm, corresponding to the CH radical emission, to pass through and attenuate all other wavelength contributions. Although there is no strict linear relation between CH intensity and heat release, for ethanol flames, CH intensity has been shown to monotonically increase with heat release (Bertran et al, 1998). A Kistler 7061 water-cooled piezoelectric pressure transducer is mounted along the combustor walls, and measures the pressure inside the combustion chamber.…”

Section: Control Of Heat Release and Pattern Factormentioning

confidence: 99%

Side Air-Jet Modulation for Control of Heat Release and Pattern Factor

Tunçer

Acharya

Cohen³

et al. 2003

Volume 2: Turbo Expo 2003

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The effect of a forced dilution air jet introduced through the combustor shell, on the air-fuel mixing in the combustion chamber has been investigated. Thermocouple based temperature measurements have been made at a number of forcing frequencies in the range of 100–1100Hz and blowing ratios in the range of 10–15. The open-loop integral flame response to forcing has also been acquired by recording pressure and heat release spectra. A CH-radical imaging technique is used to provide spatially- and temporally-resolved information about the heat release behavior. The results exhibit that the mean temperature field inside the main reaction zone can significantly be altered as a consequence of air jet modulation. The most significant effects are observed by forcing at vertical locations that are close to the dump plane. Enhancements in temperature of the order of 100–200 degrees C, and reduction in pattern factor of the order of 10% (e.g., from 1.13 to 1.03) were observed, with the lowest pattern factors achieved at the lowest forcing frequency of 100 Hz.

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Mapping of Luminescent Species in a Flame Front

Cited by 13 publications

References 12 publications

Determination of liquefied petroleum flame temperatures using emission spectroscopy

Determination of liquefied petroleum flame temperatures using emission spectroscopy

A study of adulteration in gasoline samples using flame emission spectroscopy and chemometrics tools

Side Air-Jet Modulation for Control of Heat Release and Pattern Factor

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