LAMINAR-FILM CONDENSATION INSIDE A HORIZONTAL ELLIPTIC TUBE

An analytical study is performed for condensation heat transfer with q uiescent or very slow vapor inside a horizontal elliptical tube under the simultaneous effects of the surface tension forces and gravity for ces on the condensate film. Analytical solutions for both the local co ndensate film thickness and heat transfer coefficient have been expres sed in terms of ellipticity e of the cross-section and the reverse Bon d numbers. The dimensionless mean heat transfer coefficient-NuBAR for any ellipticity e and the reverse Bond number have also been obtained in this study. The results show that the effect of surface tension has an influence on the local heat transfer coefficient and hydrodynamics characteristics inside an elliptical tube; however, the effect upon t he mean heat transfer coefficient is nearly insignificant. For the spe cial case when e = 0 (circular tube), the reduced results coincide wit h classical Nusselt-type solutions.