An investigation of condensate retention on pin-fin tubes

• Condensate retention measurements are reported on horizontal pin-fin tubes.
• Condensation was simulated by spraying R-113, water and ethylene glycol.
• Condensate retention on pin-fin tubes found to be considerably lower than the equivalent integral-fin tubes.
• A proposed semi-empirical correlation predicted the measured retention angles to within 15%.

Retention angle measurements on 15 rectangular pin-fin tubes are made under static conditions (without condensation) using water, ethylene glycol and R-113. Condensate retention angles found to be considerably larger than the equivalent integral-fin tubes (i.e. with the same fin height, root diameter and longitudinal pin thickness and spacing) in a range of 5%–60%. An expression for condensate retention angle on pin-fin tubes was proposed and found to agree with the measured retention angles to within 15%.