Conditions for the excitation of a laminar kinetic singing flame

Афанасьев, В. В.; Abrukov, S. A.; Kidin, N. I.; Kuzmin, A. K.

doi:10.1007/bf00789362

Cited by 5 publications

(4 citation statements)

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“…Surface areas of flame cones were calculated from motion-picture frames, with the shadow-gram and emission oscillogram registered simultaneously on the same film by Afanas'ev et al [17]. Most estimates in literature regard the flame shape as a cone [18]; herein we regard our flames as being close to two cones joined at their bases as illustrated in the inset of Fig.…”

Section: Heat Loss By Convection and Radiationmentioning

confidence: 97%

“…The path radiance is ignored and atmospheric transmittance is assumed to be unity, since the distance between the instrument and the pyrolysis flame is small, ∼1.7 m. Since the spectral response of the instrument is provided and the emissivity of the pyrolysis flame was determined from the FTIR spectrometer, the temperature of the pyrolysis flame is easily calculated from (17). The spectral emissivity used to determine the temperature of the pyrolysis flame corresponds to the spectral response of the instruments (CEDIP Jade infrared camera).…”

Section: Thermal Equilibrium In the Flamementioning

confidence: 99%

“…The spectral emissivity used to determine the temperature of the pyrolysis flame corresponds to the spectral response of the instruments (CEDIP Jade infrared camera). The description of the method for solving (17) for measured temperature, T , is beyond the scope of this paper as this is a routine approach. Note also that the integration limits in this equation are band limited to the frequency range within the sensitivity of the IR camera and within the range of emission wavelengths of present flames.…”

Section: Thermal Equilibrium In the Flamementioning

confidence: 99%

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Flame temperature trends in reacting vanadium and tungsten ethoxide fluid sprays during CO2-laser pyrolysis

Mwakikunga

Mudau²,

Brink

et al. 2011

Appl. Phys. B

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We observe the "invisible-to-the-naked-eye" flames of tungsten and vanadium ethoxide aerosols when ignited at moderate laser excitation (0 < P laser < 70 W) by employing an IR thermo-graphic camera. No emission is seen in the visible range whether by the visible region cameras or by spectroscopy. The emissivity of the precursor solution measured was 0.80 and 0.75 for tungsten and vanadium ethoxide, respectively. The spectral emissivities of the tungsten and vanadium ethoxide flames measured using FTIR-spectrometer were used to calculate the pyrolysis flame temperature at various laser intensities and wavelengths. New energy balance equations have been derivedthe transient temperature one extended from HaggertyCannon equation and the other based on standard resonance analysis. Fitting these models to experimental data reveals that only small amounts (1.33% and 4.32%, respectively) of the laser power are used in the pyrolysis of the precursor ethoxide aerosols into the desired oxide nanostructures. The low levels of specific heat capacity values obtained in these sprays suggest that these are electronic heat capacities rather than lattice heat capacities; enthalpies are also obtained. The experimental temperature-laser power trends observed were in agreement with previous findings from Tenegal et al. (Chem. Phys. Lett. 335:155, 2001). The damping coefficients, and hence the saturation intensities confirm that the vanadium containing precursor liquid is harder to dissociate into final products than the tungsten precursor as observed experimentally.

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Section: Heat Loss By Convection and Radiationmentioning

confidence: 97%

Section: Thermal Equilibrium In the Flamementioning

confidence: 99%

Section: Thermal Equilibrium In the Flamementioning

confidence: 99%

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Flame temperature trends in reacting vanadium and tungsten ethoxide fluid sprays during CO2-laser pyrolysis

Mwakikunga

Mudau²,

Brink

et al. 2011

Appl. Phys. B

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“…Experimental proof of oscillations in the eous medium is subject to a simple one-step exother-audible range is well documented (Sugimoto and mic Arrhenius-type reaction. They found that Matsui, 1982;Afanas'ev et al, 1995). acoustic-kinetic coupling can, depending on the sysTwo descriptions of the combustion problem are tern conditions, lead to amplification or attenuation of analy~ed in the linear stability analysis.…”

Section: Introductionmentioning

confidence: 99%

Analysis of combustion-driven acoustics

Boshoff-Mostert

Viljoen

1998

Chemical Engineering Science

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Abstract-Combustion-driven acoiistic oscillations are investigated by performing a onedimensional stability analysis of a burner-stabilized premixed flame. In contrast to other investigators, no initial acoustic wave is assumed in the analysis; the downstream acoustic field results from flame instability. Two models are considered: the thermodiRusive model (uncoupled model) and the fully coupled thermodiffusive-hydrodynamic model. The fully coupled problem exhibits instability at a much lower critical Lewis number than the uncoupled problem.

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