An experimental investigation of the effect of condensate inundation on heat transfer in a horizontal tube bundle.

Abstract

A test facility to evaluate the effect of condensate inundation on heat transfer within a horizontal tube bundle was designed, constructed and validated. Five 15.9 mm (5/8 in.) nominal outside diameter, smooth stainless steel tubes were utilized in a vertical row. They 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 the bundle. Data was taken by condensing steam at about 21 kPa (3 psia) on the outside of each tube. Each tube was cooled by water on the inside at velocities of 0.78 to 7.0 m/sec (2.56 to 23 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 tube in portions of the condenser as well as side drainage, particularly over the first three tubes. Outside heat transfer coefficients were lower than expected when compared to Nusselt theory, possibly due to the effects of secondary vapor flow and/or non-condensable gases. Recommendations to improve validation are provided.