Water Jet Exhausters and Water Jet Fans
Water jet exhausters are jet pumps designed for handling of air or gases using water under pressure as motive fluid.
Its basic principle is the following: the water issuing, through multiple nozzle and enters to the mixing trucks as high velocity jets. Those entrainment action suck up the surrounding gas and accelerate it near the water jets velocity. Then, the mixture experiment a "mixing shock" with a sudden change of the flow structure from the jet flow type to forth one, accompanied with a pressure build up and velocity reduction. At the diffuser, semi continuous mixture transforms its kinetic energy in flow work with and additional increase of pressure. Sealing of the discharge end is required to prevent back flow of air.
When a tail barometric leg come after the exhauster, a better performance result by the gravity effect on the discharge level.
Water jet fans are large entrainment capacities and low compression water gas ejector which uses little flow of motive water. Their uses the jet entrainment principle to create a draft for gas and fumes handling.
Open water circuit is possible: never less and closed one is normally used, with storage tank, pump and piping to recirculate the water.