Mixed convection film condensation from downward flowing vapors onto a sphere with variable wall temperature

Abstract

A model is developed for the study of mixed- convection film condensation from downward flowing vapors onto a sphere with variable wall temperature. The model combined natural convection dominated and forced convection dominated film condensation, concerning effects of pressure gradient (P), interfacial vapor shear drag and non-uniform wall temperature variation (A), has been investigated and solved numerically. The effect of pressure gradient on the dimensionless mean heat transfer, Nu¯Re−1/2 will remain almost uniform with increasing P until \(P={2 \over 9} F \) for various corresponding available values of F. Meanwhile, the dimensionless mean heat transfer, Nu¯Re−1/2 is increasing significantly with F for its corresponding available values of P. Although the non-uniform wall temperature variation has an appreciable influence on the local film flow and heat transfer; however, the dependence of mean heat transfer on A can be almost negligible.