Design of shell-tube condenser with finned tubes with two dimensional (2D) or three dimensional (3D) fins for HFC134a needs reliable models for the film condensation

which is usually based on reliable experimental data. A new test facility was established to investigate experimentally film condensation characteristics of HFC134a on six enhanced tubes (four kinds of 2D finned tubes and two kinds of 3D finned tubes) and the reliability of existing models and the effect of fin density and fin height on film condensation of HFC134a were discussed. Equivalent outside diameter and active length of test tubes are 19.05 and 1000 mm

respectively. In the experiment

water-side convection heat transfer coefficient for all test tubes is determined by the modified Wilson plot method. The results are as follows. Condensation heat transfer coefficient (CHTC) of HFC134a on single smooth tube is a little higher (5%—8%) than that predicted by the Nusselt model; CHTC of the best 2D (or 3D) finned tubes is 11.5 (or 19) times higher than that of single smooth tube under the same heat flux; the best fin density and fin height of 2D finned tubes are in the regions of 1069—1575 fins per meter (fpm) and 0.7—1.5 mm

respectively; the best fin density of the 3D finned tubes is less than 2000 fpm; the deviations between existing models and experimental results are not acceptable

due to their bad stability or poor accuracy. More work should be done to improve the models for film condensation of HFC134a on 2D finned tubes and develop models for that on 3D finned tubes in the future. The result can be used to guide the design of shell-tube condenser with HFC134a.