Radiating Effectiveness of Annular-Finned Space Radiators, Including Mutual Irradiation Between Radiators Elements

The heat transfer characteristics of annular fin and tube radiators have been determined analytically. The complex interaction problem resulting from mutual irradiation between neighboring fins and between fins and the tube surface has been fully accounted for by applying a newly-devised contour-integral method for deriving the radiant interchange factors. The mathematical description of the simultaneous heat transport by conduction and radiation leads to a nonlinear integro-differential equation. This has been solved for a wide range of the pertinent physical parameters. The heat transfer from the fin-tube system has been calculated and is presented graphically in dimensionless form. The separate contributions to the total of the fin and of the tube are also shown. The results definitely indicate that the use of fins leads to a significant increase in heat transfer compared with the unfinned tube.