Direct contact condensation of steam on slowly moving water

Abstract A study of direct contact condensation of stagnant saturated steam on slowly moving subcooled water has been performed with reference to a horizontal flat geometry. Inlet water mass flowrate and temperature together with inlet steam temperature have been investigated, as experimental variables, in the following ranges: 1. (a) pressure up to 6 bar, 2. (b) inlet steam temperature up to 160°C 3. (c) inlet water mass flowrate up to 120 kg/h, 4. (d) inlet water temperature up to 70°C, 5. (e) available steam mass flowrate up to 20 kg/h. Condensation heat transfer coefficients have been determined as functions of inlet water mass flowrate, inlet water and steam temperature. Heat transfer coefficient does not show, practically, dependence either on inlet water temperature or inlet steam temperature but only on inlet water mass flowrate. Correlations are given for the Nusselt number, as a function of Reynolds and Prandtl numbers. An evaluation of thermal non-equilibrium degree between the phases is also presented, together with a correlation for its prediction.