Accurate determination of view factors in axisymmetric enclosures with shadowing bodies inside

A method is presented for calculating view factors accurately in a general enclosure with shadowing objects present inside, in which the surfaces are either axisymmetric bodies of revolution or planar, which has application i n the thermal analysis of spacecraft systems. The view factor from an infin itesimally small ring element to a small band on the enclosure is evaluated by application of the contour integration method accounting for the shadow ing effect, followed by numerical integration over finite lengths and decom position rule. The solution of many practical thermal radiation problems in enclosures requires the knowledge of the view factors for a conical enclos ure inside which a coaxial cylinder is present. An analytical expression fo r the view factor from an infinitesimally small ring element on the cone to the end disk is presented. The view factors from the lateral surface of th e cone to the end disk are presented in graphical form for a representative case,which is not available in the literature. The preceding technique is applied to a sample enclosure to bring out the shadowing effect, and the re sults show an accuracy of up to six significant digits in the computed view factors.