CS-13 Shellside Condensation of Mixtures in Vertical Cross Downflow on Plain and Low-Finned Tubes

Z. H. Yang

From 2002 through FY 2005, HTRI conducted an experimental and analytical study on shellside condensation of mixtures in vertical cross downflow. Four tube bundles (one plain and three low-finned) were tested on the Multipurpose Condensation Unit (MCU). With these new data, we evaluated the existing HTRI Resistance Proration Method (RPM) and the HTRI-modified Rose-Briggs Method, both of which had previously been improved based on data for condensation of pure components with and without noncondensable gas. Comparisons indicate that the existing HTRI RPM underpredicts the heat transfer coefficient by eight to 25 percent, while the HTRI-modified Rose-Briggs Method predicts data accurately over a wide range of gravity-controlled flow regimes.

A multicomponent correction factor to the RPM and new condensate flooding retention criteria have been developed to account for the effects of mass diffusion and a flooding retention penalty in condensation of multicomponent mixtures. Our experimental data also demonstrate the advantages of low-finned tubes used in shellside condensation of mixtures. The average heat transfer enhancement ratio ranged from 1.1 to 2.2, depending on condensation process conditions and finned tube geometries. This report presents the new experimental data and summarizes the method evaluation and improvement for shellside condensation of mixtures in vertical crossflow.