Experimental Study Of Condensation Heat Transfer On R417A Outside Air-conditioning Heat Transfer Tubes

R22 have been extensively used in the central air-conditioning as refrigerants,because of the medium pressure and temperature. Studies found that R22 destroy the stratospheric ozone layer, seeking a new alternative refrigerants has become a global problem. In the alternative of R22 , Researchers have done a lot of work, and also found a lot of new ideas and methods. In according of the current level of economic and social development,using the non-azeotropic R417A refrigerant mixture is both economy and reducing the damage of the ozone layer .The experiment studies heat transfer of smooth tube and seven enhanced Tubes in R417A . The main content of this article are as follows:(1)For the experimental tubes of C31,C32,C33,C36,C38,C39,C40,The enhancement rates are from 2.2 to 2.4 and enhanced inner heat transfer.(2) For C32, C33,C36,in the heat flux ranges of experiments(q=62～150kW/m~2). External condensation heat transfer coefficients of R22 decrease with the increases of the saturated vapor temperatures.(3)For C32, in the heat flux ranges of experiments(q=83～126kW/m~2), The saturated vapor temperature's varies have a little effect on external condensation heat transfer coefficients of R417A. For C36, in the heat flux ranges of experiments(q=60～120kW/m~2), External condensation heat transfer coefficients of R417A increase with the increases of the saturated vapor temperatures. For C31,C38,C39,C40, external condensation heat transfer coefficients of R417A at the saturated vapor temperature of 35℃cross those of 40℃.(4) For C32,C33,C36, in the heat flux ranges of experiments(q=49～140kW/m~2),external condensation heat transfer coefficients of R417A are 26～60% those of R22, external condensation heat transfer coefficients of R417A are lower than those of R22.For R22, external condensation heat transfer coefficients of C36 are higher than those of C32.(5) For C40,C39,C38,C31, in the heat flux ranges of experiments(q=60～140kW/m~2), external condensation heat transfer coefficients of enhanced tubes are 7～17 times those of smooth tube for R417A, external condensation heat transfer coefficients of R417A increase with the increases of external fin numbers.