A new mechanism for condensation heat transfer enhancement: Effect of the surface free energy difference of condensate and solid surface

In order to investigate the effect of the surface free energy difference of solid surface and condensate on the condensation pattern states and heat transfer performance, two critical values of the surface free energy difference are proposed to classify the vapor condensation pattern states into film, mixing, and perfect dropwise modes. Consequently, a new condensation heat transfer enhancement mechanism in term of the surface free energy difference can be concluded. The experimental results indicate that the condensation heat transfer characteristics increase with the increasing of the magnitude of the surface-free-energy difference of the solid surface and the condensate liquid, within the film and mixing condensation regions, at the identical operating conditions.