Frictional pressure drop during steam stratified condensation flow in vacuum horizontal tube

The frictional pressure drop of steam condensation flow in vacuum horizontal tube was studied experimentally. The steam saturation temperature changes from 50 to 70 °C, the steam mass flux varies from 2 to 10 kg/(m2·s), vapor quality range are from 0 to 1 and the temperature difference between steam and cooling water are 3, 5 and 8 °C respectively. 205 experimental data were obtained in the experiment and compared with 25 existing frictional pressure drop models in three different kinds. All the experimental conditions are stratified flow and the flow states are turbulent and laminar flow in steam and liquid phase respectively. The frictional pressure drop increases with mass flux and vapor quality. It decreases with saturation temperature and has less relationship with temperature difference. Five models with the highest prediction accuracy are Quibén's model, Chisholm's model, Zhang's model, Sun's model, Lee's model.