Condensation on a Horizontal Wire-Wrapped Tube

Measurements for film condensation of steam, R113 and ethylene glycol on a horizontal wire-wrapped tube are reported. All measurements were made at near atmospheric vapor pressure and with coolant at around $20°C$⁠. Care was taken to avoid error due to the presence of air in the vapor. Complete wetting (film condensation) was observed in all cases. Wire diameter and pitch of winding were systematically varied and heat-transfer measurements made for a range of coolant flow rates. Data, in the form of heat flux and vapor-to-surface temperature difference, are presented. These were used to determine enhancement ratios (ratio of heat flux or heat-transfer coefficient for a wire-wrapped tube to the corresponding value for a plain tube at the same vapor-to-surface temperature difference). Enhancement ratios exceeding 3 for R113 and 2 for steam and ethylene glycol were obtained. The results are discussed in the light of earlier measurements and theory.