Mixed-convection laminar film condensation on an inclined elliptical tube

The present theoretical study concerns with mixed-convection laminar film c ondensation outside an inclined elliptical tube with isothermal surface. Th e assumptions used are as in the classical Nusselt-Rohsenow, theory, howeve r, with considering the interfacial vapor shear by extending a circular-tub e shear model developed in a previous study. An equivalent diameter, based on equal surface area, is introduced in the analysis to enable comparison w ith circular tubes. For zero ellipticity, the approach approach to the circ ular tube model developed in our previous work. A numerical solution has be en obtained for a wide range of the independent parameters. The results ind icate that the heat transfer performance of the inclined elliptical tribe e nhances with the increase of tube ellipticity compared to an inclined circu lar tube of equivalent diameter: For forced-convection-dominated film conde nsation, the rate of this enhancement in the heat transfer coefficient is f ound smaller than that for pure-free-convection film.