ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Effects of elongation on the radiation heat transport down a spheroidal cavity, located in a conducting solid with a diffusely reflecting cavity-solid interface, are examined. An effective conductivity λe and a void radiation conductivity λr are obtained as a function of cavity eccentricity α; and surface emissivity ε. To facilitate the calculations and produce readily applicable equations, a rigorous variational principle is used. Exact solutions are generated in the neighborhood of the spherical cavity (α2 → 0) for any ε 〉 0, a long needle-shaped void (α2 → 1) for any ε 〉 0, and a perfect reflector (ε → 0) for arbitrary elongation (0 ≤α2 ≤ 1). Significant differences arising from the shape change are observed. The α2 → 0 edge demonstrates a linear increase in λr with ε. At the opposite edge α2 → 1 and positive ε, λr is a horizontal line independent of ε, much like the long cylinder, whose conductivity is a factor of 32/(9π) (= 1.13) larger. In the neighborhood of ε 0, λr is always zero for any 0 ≤ α2 ≤ 1. The emissivity slope for ε → 0 starts from unity at α2 = 0 and increases monotonically with elongation to a singularity 3π[16(1 - α2)]-1 as α2 → 1 for the long needle.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690430103
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