Efficiency characteristics of hemi-ellipsoidal and hemispherical collectors of thermal radiation

R. P. Heinisch, E. M. Sparrow

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Collection efficiencies are determined for integrating hemi-ellipsoids and integrating hemispheres used in connection with radiation surface property measurements. The Monte Carlo method is employed to simulate the trajectories of photon bundles which leave a source of radiation and are collected and focused onto (or adjacent to) a receiver. The radiation source may be a test surface whose reflectance or emittance is to be determined, while the receiver may be a radiation detector. Results are obtained for a wide range of source and receiver sizes and positions. The results show that in the case of the hemi-ellipsoid, the attainment of good collection efficiency requires that the radius of the receiver be at least twice that of the source. The hemisphere is, in general, a less efficient collector than the hemi-ellipsoid When the source and receiver are only slightly displaced from the center of the base plane circle of the hemisphere, then the two collectors are comparably efficient.

Original languageEnglish (US)
Pages (from-to)1275-1284
Number of pages10
JournalInternational Journal of Heat and Mass Transfer
Issue number9
StatePublished - Sep 1971


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