On the potential of blow-down conditions in studies of nucleating and two-phase flows of steam

The paper examines the possibility of producing nucleation in subsonic flows of steam. Investigations of limiting supersaturation and nucleation in flowing steam are traditionally carried out under steady-state conditions where the zone of rapid condensation occurs in the supersonic part of the flow. This is not representative of nucleation in steam turbines where the flow is generally subsonic. To achieve nucleating conditions in subsonic flows requires a supercooled steam supply which is difficult to produce under steady-state conditions in the laboratory. It is shown in the paper that supercooled steam can be created by blowing down a receiver. This is followed by the description of small scale equipment constructed to test this possibility. The receiver feeds a convergent-divergent nozzle which constitutes the test section. The results presented demonstrate the validity of the procedure and its suitability for studies of nucleating and wet steam flows