The effect of a novel coating technique on filmwise and dropwise condensation of steam on horizontal tubes

摘要

Steam condensation heat transfer on smooth horizontal tubes and on a Korodense horizontal tube was experimentally studied at atmospheric pressure and at vacuum. The overall heat transfer coefficient was measured and the outside heat transfer coefficient was determined from the modified Wilson Plot Technique. A hydrophobic coating of a self-assembling monolayer (SAM) with a composition of HS(CH2)15 CH3 promoted excellent dropwise condensation (DWC) on tubes. Coexisting strips with varying widths of filmwise condensation (FWC) and DWC, but at a constant area ratio of 50%, were also investigated.