Heat transfer with refrigerant R22 boiling in horizontal smooth and finned tubes

In the report the investigation results of heat transfer with boiling of the refrigerant R22, flowing in tube with length of 1,1m and inner diameter of 17mm are presented. Smooth tube and spiral finned tube (fm height of 0,44mm, swirl angel of 12 degrees, the fin pitch of 1,55mm) was investigated. The experiments were carried out with the heat flux of 5- 15 kW/m(2), mass flux of 90- 450 kg/m(2)s, vapour quality in cross sections of 0,05- 0,7. The results of heat transfer investigation with refrigerant R22 boiling in smooth tube were compared with relations of Kandlikar, Steiner and Hihara. In the report the data of authors are compared in form of ratio of heat transfer coefficient for advanced finned surface to heat transfer coefficient for smooth tube with other authors' results for refrigerants R12, R113, R114, R22. The general regularities of mass flux (Re number for liquid) with Martinelli parameter effect on heat transfer intensity are shown. On this basis generalized dependencies for heat transfer calculation are obtained.