Effect of fin geometry on condensation of zeotropic refrigerant mixture R407C in a staggered bundle of horizontal finned tubes

摘要

Row-by-row heat transfer data were obtained during condensation of downward-flowing refrigerant mixture R407C in a staggered bundle of horizontal finned tubes. Two kinds of conventional low-fin tubes with fiat-sided annular fins and three kinds of three-dimensional fin tubes were tested. The refrigerant mass velocity ranged from 4 to 23 kg/m{sup}2s, and the condensation temperature difference from 1.5 to 12 K. At a low to medium film Reynolds number(<2000), the highest heat transfer coefficient was obtained by one of the three-dimensional fin tubes. At a high film Reynolds number (>2000), on the other hand, the highest performance was obtained by one of the low-fin tubes. For all tubes tested, the heat transfer coefficient decreased with decreasing mass velocity. On the basis of previous results for R134a, consideration was given to the characteristics of vapor phase mass transfer of R407C.