文摘
Condensation of R-134a flowing inside a dimpled tube having an inner diameter of 8.1 mm and length of 1.5 m is investigated. The test section is a horizontal counter-flow double-tube heat exchanger. The effects of heat flux, mass flux, and saturation temperature are examined. The dimpled tube enhances the Nusselt number around 1.3–1.4 times. The two-phase friction factor rises around 2.3–3.8 times as compared to the smooth tube.