9. Fluid behavior in the presence of water: water separation

Water contamination of hydraulic fluids is a frequent occurrence. Indeed, it is not uncommon for water to enter hydraulic circuits through :

• temperature exchanger leak ;

• condensation of atmospheric humidity after each shutdown (e.g. water from the compressor stage of an aircraft turbojet engine during pressurization of the hydraulic "tank" at morning startup);

• water from an external working environment penetrating through a leak (cylinder gaskets, tank seals, etc.);

• on-machine aqueous emulsification.

The ever-detrimental effects of this contamination include :

• oxidation of metals, especially ferrous metals;

• hydrolysis of certain...