Two-phase condensing tube and channel flows are widely employed in various devices of many branches of engineering (e.g., in nuclear power plants and space nuclear power plants, in solar energy converters and chemical equipment). Some of these devices are as follows:

1. Cooling radiators of space nuclear plants [131] (In this case, the waste steam is fed into the tubular condensing radiator after it has passed the turbine. Heat is removed by radiation into space from the ribs connecting the tubes along their length.)

2. Reactor cooldown systems (Steam is condensed in a tubular heat exchanger, while condensate is directed by natural circulation to the intermediate heat exchanger for heat removal from the reactor.)

3. Steam separator-superheaters (SSH) used at nuclear power plants 4. Bubbling condensers 5. Hot-air heaters for cold air preheating of gaseous and liquid fuel

preheaters prior to their compression [132,133]

Steam separator-superheaters SPP-220, SPP-500-1, and SPP-1000 have a similar design. Most completely, stable operation has been analyzed for SPP-220 [134] and SPP-500-1 [135].