The effect of condensate inundation on condensation heat transfer in tube bundles of marine condensers

Abstract

Experiments, under different conditions, were conducted to evaluate the effect of condensate inundation on condensation heat transfer in tube bundles of marine condensers. Five 15.9 mm. (5/8 in) nominal outside diameter, smooth stainless steel tubes were used in a vertical row to simulate an actual condenser. Tubes were located in an equilateral triangular array with a spacing-to-diameter ratio of 1.5. Heat transfer performance was determined for each tube in a bundle. Data was taken for condensing steam on the outside of each tube at about 21 KPa (3 psia) and at about 101 PKa (14.7 psia). Each tube was cooled by water on the inside at velocities of 0.78 to 6.22 m/sec (2.56 ft/sec to 20.42 ft/sec). The overall heat transfer coefficient was determined directly from experimental data. The inside and outside heat transfer coefficients were determined using the Wilson plot technique. Observation of condensate flow showed lateral droplet motion along the first three tubes in portions of the condenser under all conditions tested. Side drainage occurred only over the third and fourth tubes at a condensation pressure of about 21 KPa. The dominate mode of the flow at 101 KPa condensation pressure was gravitational flow. Outside heat transfer coefficients were higher than expected under all conditions when compared to the Nusselt theory. The reason for this is possibly due to secondary vapor flow. Recommendations to improve validations are provided.