Heat transfer during film condensation—uniform description of heat and mass transfer of film flows and related processes Wärmeübergang bei der Filmkondensation—Einheitliche Beschreibung des Wärme- und Stoffübergangs bei Filmströmungen und verwandten Grundvorgängen

Abstract

In this work, local heat transfer coefficients during condensation in hydrodynamically and thermally developed falling films are presented. The properties of the test substances are extensively varied. Prandtl numbers up to 52 (calculated with fluid properties at the boiling point) are obtained. The experimental determination of the mean bulk temperature of a falling film during condensation allows for the investigation of heat transfer coefficients near the wall and near the surface of the film separately. Both heat transfer resistances are compared with related heat and mass transfer processes. An improved calculation method for heat and mass transfer processes of falling films (condensation/evaporation, heating/cooling, absorption) is developed from these results.