THERMAL-DIFFUSION EFFECTS IN TURBULENT PARTIAL CONDENSATION

The coupled heat and mass transfer during partial filmwise condensation inside a vertical tube is examined. The experiments are performed with an iso-octane/nitrogen mixture at turbulent flow conditions. Special attention is paid to thermodynamic coupling due to thermal diffusion. It is found that even in turbulent flow thermal diffusion contributes significantly to the overall mass transfer rate when the temperature differences between the bulk flow and the cooled wall are large and the radial concentration gradients remain small. The experimental results are well reproduced by numerical solutions of the conservation equations with the appropriate coupling terms.