DOI: 10.1615/ICHMT.2009.CONV
ISBN Print: 978-1-56700-261-4
ISSN Online: 2642-3499
ISSN Flash Drive: 2642-3502
COMBINED FORCED CONVECTION AND SURFACE RADIATION IN CONCENTRIC ANNULI
ABSTRACT
The effects of surface radiation on the developing laminar forced convection flow of a transparent gas in concentric annuli are numerically investigated under the thermal conditions of inner wall is uniformly heated and the outer wall is adiabatic. To conduct this investigation, four shape factors not available in the literature (between a differential ring on the inner and outer surfaces of annulus and the annular opening at the inlet and the exit end of the annulus) have been derived and validated. The effect of radius ratio on thermal radiation interchange between the two walls of the annuli is presented and discussed. The effects of other controlling parameters on wall temperature and Nusslet number are illustrated. Finally, threshold values of the emissivity at which radiation effects can be neglected are obtained and presented.