Ultraviolet and visible fluorescence in the fuel pyrolysis regions of gaseous diffusion flames

Beretta, F.; Cincotti, V.; D’Alessio, Antonio; Menna, P.

doi:10.1016/0010-2180(85)90102-6

Cited by 86 publications

(38 citation statements)

References 21 publications

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“…25) and C 2 emission signals with 532-nm Nd:YAG excitation have been reported to be more than an order of magnitude less than for near resonant C 2 excitation [60]. With visible laser wavelengths, PAH-LIF signatures have been observed to be smaller than with UV excitation sources [59] and LII has been reported to dominate PAH-LIF even for even the light 0.1-ppm-level soot volume fractions encountered in our study [56]. …”

Section: Temperature [K] Temperature [K] Temperature [K]contrasting

confidence: 47%

“…Laser-induced fluorescence (LIF) from PAH species using both UV and visible laser wavelengths is well established [56,58]. Spectrally, PAH peaks just to the red of the exciting laser line and then decays to the red of the laser peak over a range of several hundred nanometers [59]. Like LII, PAH fluorescence can be exploited for diagnostics purposes or it can be a nuisance background source.…”

Section: Temperature [K] Temperature [K] Temperature [K]mentioning

confidence: 99%

See 1 more Smart Citation

Filtered Rayleigh scattering diagnostic for multi-parameter thermal-fluids measurements : LDRD final report.

Beresh¹,

Grasser²,

Kearney³

et al. 2004

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Simulation-based life-cycle-engineering and the ASCI program have resulted in models of unprecedented size and fidelity. The validation of these models requires high-resolution, multiparameter diagnostics. Within the thermal/fluids disciplines, the need for detailed, high-fidelity measurements exceeds the limits of current Engineering Sciences capabilities and severely tests the state of the art; therefore, a diagnostic development effort is warranted. The focus of this LDRD is the development and application of filtered Rayleigh scattering (FRS) for highresolution, nonintrusive measurement of gas-phase velocity and temperature. This multiparameter technique adds significant experimental capability to several Sandia programs including Fire Science and Technology (FS&T) and Aerosciences programs in the Engineering Sciences Center (9100) and Reacting Flow Research at the Combustion Research Facility (8300).With FRS, the flow is laser-illuminated and Rayleigh scattering from naturally occurring sources is detected through a molecular filter. The filtered transmission may be interpreted to yield point or planar measurements of three-component velocities and/or thermodynamic state. Different experimental configurations may be employed to obtain compromises between spatial resolution, time resolution, and the quantity of simultaneously measured flow variables. This capacity for multi-parameter, non-intrusive instrumentation represents an unprecedented advance beyond presently available techniques in the Engineering Sciences Center and in the larger scientific arena. Furthermore, measurements may be made using naturally occurring scattering centers, eliminating potentially intractable difficulties associated with particulate or chemical seeding in a hypersonic or reacting environment. Molecular-filter absorption of scattered light from solid boundaries also makes FRS advantageous for detailed boundary-layer measurements. 4These advantages make FRS an attractive alternative to developed techniques and offer a substantial payoff impacting multiple thermal/fluids disciplines. Moreover, a virtually identical experimental configuration may be utilized for both aerodynamic and thermal diagnostic applications simply by adjusting the laser and molecular filter. These measurements are ideally suited for use in production-scale facilities, where many other techniques are difficult to implement.In this report, we present the results of a three-year LDRD-funded effort to develop FRS combustion thermometry and Aerosciences velocity measurement systems. The working principles and details of our FRS opto-electronic system are presented in detail. For combustion thermometry we present 2-D, spatially correlated FRS results from nonsooting premixed and diffusion flames and from a sooting premixed flame. The FRS-measured temperatures are accurate to within ±50 K (3%) in a premixed CH 4 -air flame and within ±100 K for a vortexstrained diluted CH 4 -air diffusion flame where the FRS technique is severely tested by large variation ...

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Section: Temperature [K] Temperature [K] Temperature [K]contrasting

confidence: 47%

Section: Temperature [K] Temperature [K] Temperature [K]mentioning

confidence: 99%

Filtered Rayleigh scattering diagnostic for multi-parameter thermal-fluids measurements : LDRD final report.

Beresh¹,

Grasser²,

Kearney³

et al. 2004

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“…Then from these excited states, these PAH molecules relax to the electronic state S 1 by the internal conversion and the ro-vibrational relaxation processes. Further, these excited PAH molecules provide fluorescence by relaxing back to the ro-vibrational levels of S 0 [51,52] . In addition, the emission wavelength from an excited PAH molecule depends on the number of aromatic rings this molecule possesses, while the emission wavelength is larger for a molecule with higher number of aromatic rings [51][52][53] .…”

Section: Planar Laser Induced Fluorescence (Plif) For the Pah Measurementioning

confidence: 99%

PAH formation in counterflow non-premixed flames of butane and butanol isomers

Singh

Sung

2016

Combustion and Flame

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Butane and butanol isomers Polycyclic aromatic hydrocarbon (PAH) Soot formation PAH-planar laser-induced fluorescence (PAH-PLIF) Laser-Induced incandescence (LII) Light extinction a b s t r a c t Using the planar laser-induced fluorescence (PLIF) technique in a counterflow non-premixed flame configuration, the formation of the polycyclic aromatic hydrocarbons (PAHs) for the butane isomers and the butanol isomers was investigated. For these C 4 fuels, the PAHs of various aromatic ring size groups (2, 3, 4, and larger aromatic rings) have been characterized and compared in non-premixed combustion configuration. In particular, the formation and growth of the PAHs of different aromatic ring sizes in these counterflow flames was examined by tracking the PAH-PLIF signals at various detection wavelengths. The fuel structure effects on the PAH formation and growth processes were also analyzed by comparing the PAH growth pathways for these C 4 fuels. Furthermore, PAH-PLIF experiments were conducted, by blending each of the branched-chain isomers with the baseline straight-chain isomer, in order to study the synergistic effects, as well as identify the relative importance of the H-abstraction-C 2 H 2 -addition (HACA) mechanism and the propargyl (C 3 H 3 ) recombination/addition pathways in the PAH formation and growth processes. A chemical kinetic model available in the literature that includes both the fuel oxidation and the PAH chemistry was also used to simulate and compare the PAH species up to A 4 rings. At the incipient stage of the PAH formation, the simulated results exhibited similar behavior to the experimental observations. The PAH formation pathways considered in the chemical kinetic model were further analyzed. In addition to propargyl, the present results demonstrated the important role of acetylene in the PAH formation and growth processes.

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“…Earlier studies found that the spatial location of the maximum PAH fluorescence signals in diffusion flames depend upon the excitation and detection wavelengths [17,18]. For shorter excitation wavelengths in the visible and UV-regions, the fluorescence emission becomes stronger and its wavelength of maximum intensity shifts more to the blue than is found with longer wavelength excitations [14,16,19].…”

Section: Introductionmentioning

confidence: 95%

“…Recently, the roles of polycyclic aromatic hydrocarbons (PAHs) as soot precursors in the sooting process have been investigated in numerous works [1][2][3][4][5][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. In 1997, Vander Wal et al [13] suggested that the appearance of a ''dark'' region separating the PAH-and soot-containing regions was caused by reduced number densities of both initiated soots and large soot precursors using simultaneous laser-induced fluorescence (LIF) and laser-induced incandescence (LII) detection.…”

Section: Introductionmentioning

confidence: 99%

Study of deposit morphology in a propane diffusion-flame under fuel-rich conditions

et al. 2004

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Ultraviolet and visible fluorescence in the fuel pyrolysis regions of gaseous diffusion flames

Cited by 86 publications

References 21 publications

Filtered Rayleigh scattering diagnostic for multi-parameter thermal-fluids measurements : LDRD final report.

Filtered Rayleigh scattering diagnostic for multi-parameter thermal-fluids measurements : LDRD final report.

PAH formation in counterflow non-premixed flames of butane and butanol isomers

Study of deposit morphology in a propane diffusion-flame under fuel-rich conditions

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