Photochemical interferences for laser-induced incandescence of flame-generated soot

Goulay, Fabien; Schrader, Paul E.; Nemes, L.; Dansson, Mark A.; Michelsen, Hope A.

doi:10.1016/j.proci.2008.05.030

Cited by 52 publications

(25 citation statements)

References 58 publications

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“…A 400 nm narrowband (NB) filter (Thorlabs FB400-10) and a 450 nm NB filter (Thorlabs FB450-10) were installed in front of the objectives on the ICCDs to collect LII signals at two different wavelengths. The wavelengths were selected based on the following criteria: (a) absence of interference from C 2 clusters around 475, 518, and 560 nm (negligible within 400-456 nm (Goulay et al 2009;Michelsen et al 2015)); (b) absence of interference from red-shifted PAH LIF above 532 nm (red-shifted), which peaks around 550 nm for 532 nm excitation (Michelsen et al 2015); (c) maximization of the camera sensitivity and SNR, which becomes worse below 400 nm; (d) known relative ratios of index of refraction at each wavelength, so as to support the two-color ratio method. The use of 1064 nm for particle heating can avoid the interference from PAH LIF (Liu et al 2009), allowing a wider range of wavelengths to be used, and thus better accuracy in the determination of peak temperature.…”

Section: Methodsmentioning

confidence: 99%

Planar 2-color time-resolved laser-induced incandescence measurements of soot in a diffusion flame

Tian

Zhang

Gao

et al. 2017

Aerosol Science and Technology

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Planar two-dimensional two-color time-resolved laser-induced incandescence (2D-2C-TiRe-LII) is employed to investigate soot formation in a standard ethylene laminar diffusion flame. The time resolution of the 2D LII signal is realized by shifting the delay time of ICCD cameras. The two-color configuration is applied to measure the peak temperature T p of soot particles immediately after the laser pulse rather than using the energy balance to compute T p . The Sauter mean diameter D 32 and the corresponding distribution width parameter s of the measured soot particles is extracted by using an error minimization method. The method shows that a range of possible geometry mean particle diameters and corresponding distribution width parameters are also possible solutions, and further information on realizable particle size distribution widths is necessary to narrow down the extracted diameter. EDITOR Thomas KirchstetterCONTACT B. Tian

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Section: Methodsmentioning

confidence: 99%

Planar 2-color time-resolved laser-induced incandescence measurements of soot in a diffusion flame

Tian

Zhang

Gao

et al. 2017

Aerosol Science and Technology

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“…To minimize the influence of optical extinction on the LII measurements of soot concentration, an excitation wavelength of 1064 nm (YAG fundamental) was used in this project, which limits the extinction of the laser beam itself and also allows detection of the LII signals at wavelengths through the visible region, limiting the extinction of the LII signal in comparison to typical LII signal detection around 400 nm. Use of a long-wavelength excitation wavelength for LII also has the distinct advantage of severely limiting the extent of C 2 and C 3 LIF produced from LII excitation [95].…”

Section: Jet Flame Measurements: Laser Extinction and Correction For mentioning

confidence: 99%

Understanding and predicting soot generation in turbulent non-premixed jet flames.

Wang

Kook²,

Doom³

et al. 2010

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This report documents the results of a project funded by DoD's Strategic Environmental Research and Development Program (SERDP) on the science behind development of predictive models for soot emission from gas turbine engines. Measurements of soot formation were performed in laminar flat premixed flames and turbulent non-premixed jet flames at 1 atm pressure and in turbulent liquid spray flames under representative conditions for takeoff in a gas turbine engine. The laminar flames and open jet flames used both ethylene and a prevaporized JP-8 surrogate fuel composed of n-dodecane and m-xylene. The pressurized turbulent jet flame measurements used the JP-8 surrogate fuel and compared its combustion and sooting characteristics to a world-average JP-8 fuel sample. The pressurized jet flame measurements demonstrated that the surrogate was representative of JP-8, with a somewhat higher tendency to soot formation. The premixed flame measurements revealed that flame temperature has a strong impact on the rate of soot nucleation and particle coagulation, but little sensitivity in the overall trends was found with different fuels. An extensive array of non-intrusive optical and laser-based measurements was performed in turbulent non-premixed jet flames established on specially designed piloted burners. Soot concentration data was collected throughout the flames, together with instantaneous images showing the relationship between soot and the OH radical and soot and PAH. A detailed chemical kinetic mechanism for ethylene combustion, including fuel-rich chemistry and benzene formation steps, was compiled, validated, and reduced. The reduced ethylene mechanism was incorporated into a high-fidelity LES code, together with a momentbased soot model and models for thermal radiation, to evaluate the ability of the chemistry and soot models to predict soot formation in the jet diffusion flame. The LES results highlight the importance of including an optically-thick radiation model to accurately predict gas temperatures and thus soot formation rates. When including such a radiation model, the LES model predicts mean soot concentrations within 30% in the ethylene jet flame. 3This page left intentionally blank.

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“…Although instrumentation and interpretation are still under debate as reviewed by Schulz et al [11] and Michelsen et al [12], addressing particularly the effects of laser fluence, spectral and temporal gating, optical depth, primary particle size distribution and shape, as well as laser-induced photochemistry [13] and change of particle morphology, LII seems remarkably robust compared to the more conventional techniques for soot characterization including soot volume fraction by gravimetric or light extinction techniques [14], the multi-wavelength emission technique [15], soot morphology (primary particle diameter and aggregate size distribution) determination by laser scattering [16] as well as thermophoretic sampling/ transmission electron microscopy particle diagnostic [6,17] or laser-induced fluorescence (LIF) which is based upon measurements of the fluorescence of C 2 molecules from vaporized soot [18,19].…”

Section: Introductionmentioning

confidence: 99%

Soot characterization with laser-induced incandescence applied to a laminar premixed ethylene–air flame

Hadef

Geigle

Meier

et al. 2010

International Journal of Thermal Sciences

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a b s t r a c tLaser-induced incandescence (LII) has emerged as a promising non-invasive technique for measuring spatially and temporally resolved soot volume fraction and size. In this investigation we try to assess its performance in more detail by characterizing primary particle sizes using time-resolved LII and soot volume fractions by 2D LII. The experiments were performed at a fixed location in premixed ethylene/air flames burning on a sintered stainless-steel plug (McKenna) burner with varying values of the equivalence ratio for primary particle sizing and on the burner axis for concentration measurements. Maximum soot concentrations follow a power law behavior with equivalence ratio. The primary particle sizes obtained from LII decay curves are in good agreement with the values measured by other techniques and show a clear rise of particle size with equivalence ratio. The data analyzed with the help of a validated LII model will be useful for the further development of soot formation models.

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Photochemical interferences for laser-induced incandescence of flame-generated soot

Cited by 52 publications

References 58 publications

Planar 2-color time-resolved laser-induced incandescence measurements of soot in a diffusion flame

Planar 2-color time-resolved laser-induced incandescence measurements of soot in a diffusion flame

Understanding and predicting soot generation in turbulent non-premixed jet flames.

Soot characterization with laser-induced incandescence applied to a laminar premixed ethylene–air flame

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