Obobshchennye raschetnye zavisimosti dlya opredeleniya intensivnosti teploobmena pri kipenii smesevykh khladagentov

The results of the experimental research of the heat exchange at bubble boiling of R404А, R407С and R410А refrigerants on finned tubes are cited. The experiments were carried out at 13...28,5 оС saturation temperatures. It was established by experiments as well as theoretically that at the developed bubble boiling the intensity of the heat transfer didn’t depend on the type or profile of the nonisothermic finned surface but it was defined only by operation parameters, thermophysical properties of the liquid, geometrical dimensions of the finned surface as well as by the internal characteristics of the boiling process. The heat transfer coefficients at the refrigerant boiling on a finned surface was rather higher than on the smooth one, i.e. at developed bubble boiling the heat exchange on finned surfaces was 2-4 times higher than on the smooth ones. The empiric dependences were defined that allowed finding the heat transfer coefficient at R404А, R407С and R410А refrigerants boiling on the finned surface of a big volume; they were satisfactorily agreed with the experimental data, the error was 15-20%. The possibility of using the derived dependences to calculate heat exchange apparatuses of the evaporating type with finned surfaces was shown. Keywords: heat exchange at boiling, vaporization, mixed ozone safe refrigerant, heat exchange intensity, heat transfer coefficient, finned surfaces, evaporator, heat exchange apparatus, refrigerating plant, empiric dependence.

теплообмен при кипении, парообразование, смесевой озонобезопасный хладагент, интенсивность теплообмена, коэффициент теплоотдачи, оребренные поверхности, испаритель, теплообменный аппарат, холодильная установка, эмпирическая зависимость