Directional spectral emittance of ceramic material - Comparison of theoretical prediction and experimental data

Lopes, Rogério; Moura, Luís; Delmas, A.; Sacadura, J. F.

doi:10.2514/6.1998-2934

Cited by 3 publications

(2 citation statements)

References 15 publications

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“…On the other hand, bidirectional data acquisition involves long and careful measurements proceeded by a delicate alignment of the setup, both requiring a highly experienced operator. Figure 5 shows the facility developed by Lopes et al [83] for spectral directional emission measurements at high temperatures. Heating isothermally up to high temperature a sample that may be a poor thermal conductor, without placing it inside a furnace, is a real challenge.…”

Section: Experimental Determinationmentioning

confidence: 99%

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Thermal Radiative Properties of Complex Media: Theoretical Prediction Versus Experimental Identification

Sacadura

2011

Heat Transfer Engineering

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In many engineering applications and natural phenomena, thermal radiation interacts with complex media composed of dispersed phases that may be of different type: solid/solid, solid/gas, or liquid/gas. Most of them are semitransparent media that emit, absorb, and scatter thermal radiation. Heat transfer by combined radiation with conduction or convection in such media is a problem of high practical importance, mostly in situations where radiation is a dominant mode. Improvement of thermal performance of such materials or of the manufacturing processes that involve these media requires the availability of efficient methods (i) for radiative transfer modeling, and (ii) to predict and to experimentally determine the thermophysical properties intended to feed the models. This paper is focused on radiative properties assessment. After a brief overview of the materials and properties of interest, the emphasis is put on methodology of property investigation combining both theoretical prediction and experimental identification. Examples related to different particulate media are presented, showing recent advances and needs for further investigation.

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Section: Experimental Determinationmentioning

confidence: 99%

“…A possible issue consists of simultaneously heating with equal power incident fluxes both sides of a thin sample, by using lasers or arc lamps. This was adopted by Lopes et al [83,84] in the facility shown on Figure 5.…”

Section: Experimental Determinationmentioning

confidence: 99%

Thermal Radiative Properties of Complex Media: Theoretical Prediction Versus Experimental Identification

Sacadura

2011

Heat Transfer Engineering

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Directional Spectral Emittance of a Packed Bed: Correlation Between Theoretical Prediction and Experimental Data

Lopes

Moura

Baillis

et al. 2000

Journal of Heat Transfer

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Directional spectral emittance of an absorbing and scattering isothermal system of packed spheres is predicted by a radiative model based on the discrete ordinates method. Radiative properties for the bed of packed opaque spheres are obtained using geometric optics laws corrected with a scaling factor to take into account the dependent scattering. This model requires the knowledge of several parameters. Particle diameter and porosity can be easily obtained, but particle hemispherical spectral reflectivity is very difficult to obtain a priori. This particle reflectivity is determined by an identification method (Gauss method of linearization) applied to bidirectional spectral reflectance data obtained from an experimental device using a Fourier transform infrared spectrometer. Directional spectral emittance is measured using a direct radiometric technique that has been recently proposed. For a system of packed opaque spheres at high temperature, good agreement is observed between experimental results of directional spectral and computed theoretical data.

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Directional Spectral Emittance of a Packed Bed: Influence of the Temperature Gradient in the Medium

Baillis

Sacadura

2002

Journal of Heat Transfer

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Recently a new experimental set-up for measuring the directional spectral emittance has been developed. Both sides of packed opaque spheres are simultaneously heated with identical power laser beams (CO2 10.6 μm) and the isothermal condition in the medium is assumed. In this paper we consider the coupled conduction-radiation equations to investigate the effect of the temperature nonuniformity on the calculated value of the emittance and to verify if the isothermal assumption is valid. Moreover, the sensitivity of the emittance and the temperature profile to the values of parameters (such as the porosity, the face temperatures, and the particle hemispherical reflectivity, etc.) is studied.

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Directional spectral emittance of ceramic material - Comparison of theoretical prediction and experimental data

Cited by 3 publications

References 15 publications

Thermal Radiative Properties of Complex Media: Theoretical Prediction Versus Experimental Identification

Thermal Radiative Properties of Complex Media: Theoretical Prediction Versus Experimental Identification

Directional Spectral Emittance of a Packed Bed: Correlation Between Theoretical Prediction and Experimental Data

Directional Spectral Emittance of a Packed Bed: Influence of the Temperature Gradient in the Medium

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