MIXED-CONVECTION FILM CONDENSATION ON A HORIZONTAL ELLIPTIC TUBE WITHUNIFORM SURFACE HEAT-FLUX

A model is developed for the study of the process of mired-convection film condensation heat transfer with downward flowing vapor condensati on onto a horizontal elliptical tube with uniform surface heat flux. A nalytical analysis for both local condensate pm thickness and heat tra nsfer coefficient accounting for the interfacial vapor shear and press ure gradient effects around the elliptical periphery have been present ed for various values of eccentricity e, including two special objects : a circular tube (e = 0) and a vertical plate (e = 1.0). The dimensio nless mean heat transfer coefficient, <(Nu)over bar>Re-1/2, increases with increasing eccentricity. III addition, the dependence of the mean heat transfer coefficient on the effects of the dimensionless pressur e gradient and the Grashof parameter is also discussed.