HEAT-TRANSFER DURING FILM CONDENSATION OF R-123 VAPOR ON HORIZONTAL INTEGRAL-FIN TUBES

This paper deals with an experimental study of heat transfer during co ndensation of R-123 vapour on horizontal integral-fin (HIF) tubes. R-1 23 is a substitute for R-11, which is required to be phased out The ef fect of a number of important geometrical parameters like the fin spac ing, fin height, and fin shape has been investigated Data have also be en obtained by condensing R-ll vapour on some of the tubes, thereby fa cilitating a direct comparison. For R-123 condensation, the best perfo rmance was obtained with a tube with fin base spacing, fin height and fin tip thickness of 0.33, 1.29 and 0.14mm respectively. This tube yie lded an enhancement ratio of around 9 at Delta T of 4K. Further, the r esults indicate that the performance of the tubes yielding high heat f lux values is sensitive to the shape of the fin profile, particularly at small fin dimensions. The tests conducted with R-11 yield a 10 to 1 5% better performance compared to R-123. This paper also deals with th e development of a generalized correlation to determine the heat trans fer performance of HIF tubes. The present experimental data as well as extensive data obtained by earlier investigators for other fluids wer e made use of in developing the correlation. The correlation predicts the heat transfer performance of all the fluids well and of refrigeran ts like R-123 and R-ll very well.