Numerical investigation on the effects of steam and water parameters on steam jet condensation through a double-hole nozzle

Steam jet condensation through multi-hole nozzles in a pressure relief pool is important for the design and safe operation of a nuclear reactor system. In this study, stable steam jet condensation through a double-hole nozzle was investigated at different water temperatures and steam pressures by CFD method. Simulation results indicated that the shape of steam cavity changed from conical to ellipsoidal with an increase in water temperature and steam pressure, and steam jet length gradually increased. Meanwhile, the interaction between two steam cavities was enhanced and they even merged under certain conditions. Expansion and compression waves were found by analyzing the thermal hydraulic parameters along the hole centerline. Water temperature and steam pressure exerted different effects on the intensity of expansion/compression waves and the positions of maximum expansion/compression. Finally, thermal hydraulic parameters along the nozzle centerline were analyzed. Steam volume fraction, temperature, and velocity initially increased and then decreased as axial distance increased, which appeared as evident peaks under the present conditions. When water temperature and steam pressure increased, the peak values of steam volume fraction, temperature, and velocity gradually increased and their positions moved downstream.