摘要：This paper presents the effect of pin fin rotational angle on the condensate retention as function of vapour velocity (0–20 m/s) on four different pin fin tubes, by systematically changing the pin fin angle from 0° – 45° with horizontal axis. While other parameters of pin fin tubes like tooth height, tooth thickness, longitudinal spacing inner and outer diameter remain constant for all 4 tubes tested. Three fluids (2-propanol, distilled water and ethylene glycol) with varying surface tension to density ratio are tested. Experimentation is conducted in a vertical wind tunnel by downward supply of air (to simulate vapour) with velocity from 0 - 20 m/s. By accurate small holes on upper side of the tube a constant flow of condensate was assured on a tube to be tested. At almost all vapour velocities; it is observed that retention angle increases with increase in pin fin angle for all fluids tested. As the vapour velocity increased from 0 to 20 m/s, it is observed that the retention angle for tube A1 increased for all test fluids, whereas with increasing velocity, a decrease in retention angle is observed for tubes A2, A3 and A4 for all fluids tested.
关键词：Condensation heat transfer ; condensate retention ; Retention angle ; Pin fin tubes with varying pin angle ; Vapour velocity
