Water injection systems are predominantly useful in forced induction (turbocharged or supercharged), internal combustion engines.

water injection, also known as anti-detonant injection (ADI), can spray water into the incoming air or fuel-air mixture, or directly into the cylinder, in order to cool certain parts of the induction system where "hot points" could produce premature ignition. In jet engines it is used to increase the thrust of the engine at low speeds and at takeoff.

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A water injection or fuel injection in the form of a fine mist, into a gaseous media is achieved through atomization.

The atomization of any fluid depends on

• Physical properties (like Surface tension, Pressure, Viscosity etc.) of the fluid at the given operating temperature.
• Properties of the gaseous media (like pressure, density etc.) into which the spray is directed.
• Geometrical parameters of Nozzles that are normally used for atomization.