Combined free and forced convection laminar film condensation on an inclined circular tube with isothermal surface
The author studies laminar film condensation of a viscous incompressible fluid on an inclined circular tube, in the regime of combined free and forced convection. The assumptions employed in the problem formulation are: 1. Condensate film thickness is much smaller than the tube diameter; 2. Inertia and pressure terms in the momentum equation and convective terms in the energy equation for the condense film can be neglected; 3. Surface tension effect is insignificant; 4. The condensate film flow is laminar, steady and with negligible viscous dissipation; 5. All physical properties of the condensate film are constant. Based on these assumptions, the author obtains analytical solutions of the governing equations which in special cases, provide known analytical solutions for horizontal and vertical tubes. On the other hand, an additional numerically obtained solution demonstrates the effects of vapour velocity and gravity force on local and mean Nusselt numbers. In the case of an inclined tube of infinite length, based on numerical results, an explicit expression has been obtained for the mean Nusselt number on the whole tube surface.
scientific article; zbMATH DE number 1395974