Condensation of R-134a on Horizontal Enhanced Tubes Having Three-Dimensional Roughness

Abstract

Enhanced tubes are widely used in shell and tube condensers of refrigeration, air-conditioning and process industries because of their high heat transfer performance. In this study, condensation heat transfer tests were conducted for four three-dimensional enhanced tubes having different fin density and fin height using R-134a. The satuartion temperature was 40[Formula: see text]C. The heat transfer was significantly enhanced by the present enhanced geometry. At 5[Formula: see text]K wall subcooling, the enhancement ratio is 6.3 for 1654[Formula: see text]fpm, 4.6 for 1575[Formula: see text]fpm, 4.0 for 1496[Formula: see text]fpm and 3.3 for 1102[Formula: see text]fpm tubes. Within the geometric variation of the present study, the condensation heat transfer coefficient increased with the increase of fin density and of fin height. The heat transfer coefficients of the 1654[Formula: see text]fpm tube were approximately the same as those of the commercial three-dimensional enhanced tube Turbo-C.