Experiment study on steam-water direct contact condensation in water flow in a Tee junction

•Six typical condensation models are observed through large numbers of visual experiments.•Regime diagrams are established based on steam and water parameters.•The dimensionless steam plume length is in the range of 0.8–3.2 for jet flow.•The average heat transfer coefficient is in the range of 0.3–1.7MW/m2K for jet flow. The phenomenon of direct contact condensation is an important process encountered in many engineering fields. In this paper, experiments are performed to investigate the direct contact condensation of saturated steam discharged directly into sub-cooled water flow in a Tee junction. A high-speed camera was employed to record the steam-water interface variation in the visualized experiment rig. The experimental results show that, six typical different condensation models are observed and a regime diagram is established based on steam mass flux, water volume flow rate and temperature. Additionally, for large chugging, the maximum elevation of level of water sucked up into the branch pipe decreases with the increase of water temperature and volume flow rate as well as steam mass flow rate. For jet flow, the dimensionless steam plume length and average heat transfer coefficient are found to be in the range of 0.8–3.2 and 0.3–1.7MW/(m2K), respectively. Furthermore, empirical correlations for the dimensionless steam plume and average heat transfer coefficient are developed.