Pressure Elevation of High-Performance Steam-Water Condensing-Injector

•Steam-Water Condensing-Injector (SI)’s pressure elevation mechanism was investigated through experiment•Experiments were carried out to obtain axial pressure and temperature profiles of central-water jet SI.•SI's heat transfer capability under steam-water direct contact condensation was assessed.•One-dimensional analytical model was implemented to assess SI's axial pressure distribution. The steam-water condensing injector (SI) is a device capable of producing high-pressure subcooled liquid streams by combining steam and subcooled liquid jet at a higher pressure than the inlet streams. The present study investigated the SI's pressure elevation mechanism using supersonic steam and a subcooled water jet. The experiment was carried out using central-water jet type SI equipped with an overflow port at the inlet steam pressures of 0.3 to 0.7 MPa and inlet liquid mass flow rates of 0.4 to 0.7 kg/s. Axial pressure and temperature distributions were measured at the mixing nozzle and diffuser sections to study the pressure elevation mechanism. Based on the analytical foundation laid by Grolmes (1968), the one-dimensional analytical model was implemented by treating SI's two-phase flow regimes as inverted annular and dispersed flows. For the current SI geometry and operating conditions, the present one-dimensional model could predict the axial pressure distribution of the SI and the maximum discharging pressure with reasonable accuracy for sufficiently high inlet flowrate ratio conditions.