Journal ArticleDOI
Visible and near-infrared emittance of ablation chars and carbon.
C. R. Spitzer,R. G. Wilson +1 more
TLDR
In this paper, a double-ellipso idalmirror reflectometer that utilizes a carbon arc to heat and to irradiate the materials was used to measure the visible and near-infrared spectral reflectance and emittance of ablation chars, carbon, and graphite at temperatures ranging from 2200° to 3500° K.Abstract:
Initial results of an experimental study of the visible and near-infrared spectral reflectance and emittance of ablation chars, carbon, and graphite at temperatures ranging from 2200° to 3500° K are presented Reflectance measurements were made with a double-ellipso idalmirror reflectometer that utilizes a carbon arc to heat and to irradiate the materials The ablation materials, from which the chars were formed by thermal degradation in atmosphericentry-simulation facilities, included high-density and low-density phenolic-nylon, carbonfiber-reinforced phenolic, and honeycomb-reinforced, low-density filled epoxy Measurements were made on a dense high-purity and a porous grade of carbon and on high-purity, structural, and pyrolytic grades of graphite A photomultiplier and a lead sulfide cell were used as detectors for the visible and infrared measurements, respectively The results indicate that emittance for all the materials is maximum in the visible spectrum and decreases with wavelength in the near-infrared spectrum The angular distributions of radiation fluxes incident on, reflected from, and radiated from, each material, were measured with an array of solar cells The distribution measurements showed that the materials whose surfaces are porous or have been roughened by oxidation obey Lambert's cosine law approximately in the emission of radiation, and also in reflecting the arc incident radiation, although the incident radiation is nonuniform in distributionread more
Citations
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Journal ArticleDOI
Ablation of ATJ Graphite at High Temperatures
John H. Lundell,Robert R. Dickey +1 more
TL;DR: In this paper, an extensive experimental program on the ablation of ATJ graphite in air at surface pressures of 0.3 to 4.4 atm and surface temperatures of 2570 to 4030 K is presented.
Journal ArticleDOI
Ablation of Graphitic Materials in the Sublimation Regime
John H. Lundell,Robert R. Dickey +1 more
TL;DR: A large variety of graphitic materials have been tested in an arc heated air stream at a surface pressure of 4.3 atm and a nominal surface temperature of 3925 K.
Journal ArticleDOI
Spectral emissivity measurements of ablating phenolic graphite.
John H. Chang,George W. Sutton +1 more
TL;DR: The surface spectral radiance of ablating phenolic graphite was measured in the wavelength region between 0.3 and lO.Sju as mentioned in this paper, and the spectral emissivity data showed that the ablating graphite radiates nearly as a grey body in the visible and near-infrared spectrum of 3 to 10.5/z.
References
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A new determination of the emissivity of tungsten ribbon
TL;DR: In this paper, a new determination of the spectral emissivity of tungsten has been performed in order to supply more reliable data for the use of the Tungsten striplamp as a standard source of radiation.
Journal ArticleDOI
The normal spectral emissivity of isotropic and anisotropic materials
G.W Autio,E. Scala +1 more
TL;DR: In this paper, the correlation of structural anisotropy with the normal spectral emissivity of pyrolytic graphite is discussed relative to polycrystalline graphite and to isotropic single crystal nickel.
Journal ArticleDOI
The Absolute Spectral Diffuse Reflectance of Magnesium Oxide in the Near Infrared
Journal ArticleDOI
Shock-Tube Studies of Equilibrium Air Radiation
TL;DR: In this paper, the results of an experimental investigation of equilibrium air radiation in the wavelength region of 0.17 to 6.0 ju are presented using a thin-film heat transfer gage to measure the stagnation-point, equilibrium radiative heat transfer rate on hemispherical models mounted in an arc-driven, shock-tube facility.
Book ChapterDOI
The spectral and integrated emissivity of carbon and graphite
J.D. Plunkett,W.D. Kingery +1 more
TL;DR: In this article, the spectral and integrated emissivities of a typical carbon, graphite, and pyrolytic graphite possessing different surfaces were measured over the temperature range of 850° to 1800°C, utilizing an emissivity apparatus based upon a modification of the Fery rotating sample method.