Steam condensation in horizontal and inclined tubes under stratified flow conditions

Abstract

In this study, an experiment on condensation heat transfer was conducted to develop a condensation model considering the structure of separated flow patterns. Multidimensional local condensation heat transfer parameters were measured in pure saturated steam at pressures of 1–5 bar and mass fluxes of 10–50 kg/m2 s in an inclinable tube with an inner diameter of 40 mm and a length of 3 m. A heat partition angle, which separated the upper and lower heat transfer areas for film condensation and convective heat transfer in stratified flow, was obtained based on the inflection point of the circumferential distribution function of local heat flux. A new condensation heat transfer model consisting of the heat partition angle and heat transfer coefficient correlations was developed based on the local heat transfer data. The experimental data for model development were obtained using circular tubes with inner diameters of 30–45 mm and inclination angles of 0–10° under pure saturated steam conditions at pressures of 1–67 bar and mass fluxes of 10–329 kg/m2 s. The model predicted the average heat transfer coefficient with an average deviation of 6.2% against the present experimental data.