Prediction of onset of boundary layer transition in film condensation on a horizontal elliptical cylinder

Abstract

This article is devoted to a numerical study of prediction of the onset of the boundary layer transition in ®lm condensation of pure saturated vapor on a horizontal elliptical tube, under the simultaneous effects of gravity, shear stress, and the imposed pressure gradients, caused by the vapor¯ow and curvature, on the condensate ®lm. The inertia and convection terms are retained in the analysis. The hypothesis of Shekriladze and Gomelauri is used at the liquid±vapor interface. Outside the boundary layer, the vapor phase velocity is obtained from potential¯ow. Temperature, velocity distribution, and dimensionless apparent turbulent stress of the fully developed¯ow are carried out using the implicit Keller method. The effects of pressure gradients characterized by Froude number, ellipticity, and Bond number on the transition position have been evaluated. The transition criterion has been given in terms of the critical ®lm Reynolds number (Re G ) C .

Forced Convection in Film Condensation on a Horizontal Elliptical Tube

“…5. The transition criterion is given in terms of the critical film Reynolds number (Re = 4 µ l ) C = 50 [12]. 6.…”