1. Operating principle and geometric characteristics of ejectors

1.1 Operating principle

Ejectors are static devices used to suck in, compress or mix gases, vapors or liquids, thanks to the expansion of a driving (or primary) fluid. The primary fluid, which may be gaseous (subsonic or supersonic) or liquid (incompressible), provides the energy required to drive the secondary fluid.

A conventional ejector, as shown in figure 1 The fan comprises a motor nozzle (or primary nozzle) and a suction nozzle (also known as a secondary nozzle or return nozzle). The latter comprises a constant-section intake chamber for mixing the two fluids, and a diffuser.