Dropwise Condensation Heat Transfer Enhancement on Silver Coated Copper Surface using n-Heptane as Surfactant Additive

Abstract: Condensation is one of the most important phenomenons of the heat transfer. A condensation occurs only when a saturated or superheated vapour is brought in contact with surface temperature below the vapour saturated temperature. According to the geometry of appearance, condensation occurred may be either film wise or drop wise. In drop wise condensation, heat transfer coefficient is comparatively higher than that of the film wise condensation. But drop wise condensation is difficult to achieve and sustain over period of long time. It can be achieved by coating the surface and using surfactant additives. So, on the bare copper tube silver coating is done and n-Heptane is used as surfactant additive to enhance the condensation heat transfer coefficient. The additive concentration has been varied from 0 % to 2 % by weight in the steps of 0.4%. Enhancement up to 57% is obtained for the silver coated tube over the bare copper tube. Keywords: dropwise condensation, additive, n-Heptane, coating, condensation heat transfer