Condensation with non-condensing gases inside vertical tubes with turbulent gas and film flow

Abstract

Mass transfer coefficients in the turbulent gas flow of a vertical condenser tube are determined experimentally in a short test segment. When the film model is used to evaluate the data, the gas phase resistance to mass transfer is well described by a correlation obtained from single-phase pipe flow. No significant interaction between gas and film flow is observed, neither for laminar nor for turbulent film flow. A design method for long condenser tubes is developed considering superheating of the gas and subcooling of the falling film. When the film model and a single-phase pipe flow correlation are incorporated, the method matches with sufficient accuracy experimental data taken from the literature. To estimate the onset of entrainment in falling film exchangers a correlation for entrainment in annular two-phase flow is checked. The calculations are in good agreement with experimental data obtained in a long adiabatic tube.