Numerical Modeling of Annular Film Condensation Inside a Miniature Tube
Résumé
This paper presents the mathematical formulation of forced convection condensation of pure fluid and binary zeotropic mixtures. The efficient of the present physical model is in solving the coupled heat and mass transfers equations and in taking into account the variation of the condensate film thickness because of the capillary effects and the dynamic flow. The numerical algorithm for the whole non-linear governing equations was iterated and produced excellent convergence behavior. The numerical results were validated by comparison with the previously experimental results [5, 17] that obtained for condensation inside a mini scale tube. For the same vapor Reynolds number, reducing the tube diameter increases the average heat transfer and decreases the friction factor. Effects of tube diameter on the condensate film thickness, pressure, and local axial velocity were examined. For the same vapor Reynolds number, the average heat transfer for condensation of mixture R123/R134a is increased by decreasing the concentration of R134a in the mixrure.