Augmentation of heat transfer during filmwise condensation of steam and R-134a over single horizontal finned tubes

An experimental investigation has been carried out to augment the heat transfer rate by enhancing the heat transfer coefficient during the condensation of pure vapours of steam and R-134a over horizontal finned tubes. The study was conducted for plain tubes, circular integral-fin tubes (CIFTs), spine integral-fin tubes (SIFTS) and parially spined circular integral-fin tubes (PCIFTs). The SIFT out performed the LIFT for the condensation of R-134a by approximately 16%. However, the spines were found most effective in the bottom side of the LIFT. The PCIFTs with the spines only in the bottom side of the tube augmented the heat transfer coefficient by 20% and 11% for the condensation of steam and R-134a, respectively, in comparison to the LIFT. (C) 2001 Elsevier Science Ltd. All rights reserved.