Optical constants of carbons and coals in the infrared

Foster, Paul J.; Howarth, C. R.

doi:10.1016/0008-6223(68)90016-x

Cited by 170 publications

(40 citation statements)

References 7 publications

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“…Figure 3a shows the absorption efficiency of coal and ash particles calculated with Mie theory in the spectral region of particular interest for this study. The complex index of refraction of the coal particles is based on data presented by Foster and Howarth, 32 and the particle diameter is 40 μm. The complex index of refraction of the ash particles is taken from refs 33−35, as presented in ref 27, and the diameter is assumed to be 10 μm.…”

Section: Methodsmentioning

confidence: 99%

Measurement and Modeling of Particle Radiation in Coal Flames

et al. 2014

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This work aims at developing a methodology that can provide information of in-flame particle radiation in industrial-scale flames. The method is based on a combination of experimental and modeling work. The experiments have been performed in the high-temperature zone of a 77 kW th swirling lignite flame. Spectral radiation, total radiative intensity, gas temperature, and gas composition were measured, and the radiative intensity in the furnace was modeled with an axisymmetric cylindrical radiation model using Mie theory for the particle properties and a statistical narrow-band model for the gas properties. The in-flame particle radiation was measured with a Fourier transform infrared (FTIR) spectrometer connected to a watercooled probe via fiber optics. In the cross-section of the flame investigated, the particles were found to be the dominating source of radiation. Apart from giving information about particle radiation and temperature, the methodology can also provide estimates of the amount of soot radiation and the maximum contribution from soot radiation compared to the total particle radiation. In the center position in the flame, the maximum contribution from soot radiation was estimated to be less than 40% of the particle radiation. As a validation of the methodology, the modeled total radiative intensity was compared to the total intensity measured with a narrow angle radiometer and the agreement in the results was good, supporting the validity of the used approach.

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Section: Methodsmentioning

confidence: 99%

Measurement and Modeling of Particle Radiation in Coal Flames

et al. 2014

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“…Electronic transitions at ultraviolet wavelengths result in narrow peaks in absorption (e.g., Sakata et al 1995). Both real and imaginary refractive indices are greater and non-constant at infrared wavelengths (e.g., Dalzell and Sarofim 1969;Foster and Howarth 1968;Jäger et al 1998).…”

Section: Beyond 550 Nmmentioning

confidence: 99%

Light Absorption by Carbonaceous Particles: An Investigative Review

Bond

Bergström

2006

Aerosol Science and Technology

2,455

135

2,375

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The optical properties of the light-absorbing, carbonaceous substance often called "soot," "black carbon," or "carbon black" have been the subject of some debate. These properties are necessary to model how aerosols affect climate, and our review is targeted specifically for that application. We recommend the term light-absorbing carbon to avoid conflict with operationally based definitions. Absorptive properties depend on molecular form, particularly the size of sp 2 -bonded clusters. Freshly-generated particles should be represented as aggregates, and their absorption is like that of particles small relative to the wavelength. Previous compendia have yielded a wide range of values for both refractive indices and absorption cross section. The absorptive properties of light-absorbing carbon are not as variable as is commonly believed. Our tabulation suggests a mass-normalized absorption cross section of 7.5 ± 1.2 m 2 /g at 550 nm for uncoated particles. We recommend a narrow range of refractive indices for strongly-absorbing carbon particles, of which the highest is 1.

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“…The coal and ash properties are calculated with the Mie-theory assuming spherical particles with a complex index of refraction for the coal particles taken from Ref. [29], and from Refs. [30][31][32] as presented in Ref.…”

Section: Radiation Modellingmentioning

confidence: 99%