An investigation of condensate retention on pin-fin tubes

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%.