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Thermal radiation of gas/solid mixtures
Author(s) -
Elsner Thomas,
Köneke Dieter,
Weinspach PaulMichael
Publication year - 1988
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.270110131
Subject(s) - emissivity , heat exchanger , quartz , particle (ecology) , materials science , thermal radiation , solid surface , thermal , absorption (acoustics) , radiation , mineralogy , solid solution , mechanics , thermodynamics , composite material , chemistry , optics , metallurgy , physics , geology , oceanography , chemical physics
Thermal radiation of gas/solid mixtures in high‐temperature heat exchangers is of considerable importance for the design of heat exchange surfaces. Therefore, an experimental plant was constructed to measure solid particle emissivities, since there is a lack of relevant data in the existing literature. A theoretical equation was derived to describe the solid particle emissivity as a function of layer thickness, specific solid surface area, solid loading and absorption and scatter coefficients. Measurements were carried out for fluidized bed ash and quartz sand. The emissivities of these particle fractions increase with increasing layer thickness, slid loading, specific solid surface area and temperature. The description of these data by the derived model equation is very satisfactory. No dependence on wavelength was observed. The ash components do exert some influence which, for the present, cannot be described exactly.