Experimental investigation of condensate retention on horizontal pin fin tube with varying pin angle

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 - 20m/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 20m/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.