Experimental research on steam condensation in presence of non-condensable gas under high pressure

Highlights: • An experimental study on steam condensation heat transfer in presence of non-condensable gas under high pressure up to 4.12 MPa were conducted. • The increase in pressure or decrease in the mass fraction of non-condensable gas would enhance the steam condensation heat transfer. • A significant increase of 98.2% in condensation heat transfer coefficient of steam with 10% Ar was obtained as the system pressure increased from 1.76 MPa to 3.12 MPa. With a great level of safety and reliability, an integrated steam-gas pressurizer is applied in the NHR-200 reactor. This work provided a solid experimental database regarding the pure steam, steam-Nitrogen and steam-Argon condensation under high pressure, which could be used to support the thermohydraulic analysis in steam-gas pressurizers of small modular reactor. The pressure ranged from 0.21 to 4.12 MPa. Benchmark experiments with pure steam found that the condensation heat transfer coefficient increased with pressure, but the response characteristics to specific pressure ranges were inconsistent. As is the case at low pressures, the introduction of non-condensable gas would weaken the steam condensation heat transfer. In particular, under high pressure, the effects of pressure on steam condensation depends highly on the species of non-condensable gas. A significant increase of 92.1% in condensation heat transfer coefficient of steam with 10% Ar was obtained as the pressure increased from 1.76 to 3.12 MPa.