AN EXPERIMENTAL-STUDY OF R-11 AND R-12 FILM CONDENSATION ON HORIZONTAL INTEGRAL-FIN TUBES

Experimental results on heat transfer during film condensation of stat ionary pure vapor refrigerants R-11 and R-12 on a smooth tube and on f our tubes with transverse ribs of constant curvature are reported. The tubes were manufactured in such a way that the fins and valleys had c ircumferences of the same radius. All tubes were made of brass. The ef fect of surface curvature on heat transfer was studied. The heat trans fer coefficient on the finned tubes (based upon the smooth tube surfac e area having the diameter of the fin root) increased in all cases. Th e maximum enhancement being obtained with the tube having the smallest fin radius. Experimental data have been compared with the theoretical models of condensation on the curvilinear surfaces. They have also be en processed in dimensionless form.