What occurs to air density when water injection is applied during engine operation?

When water injection is applied during engine operation, it results in an increase in air density. This phenomenon occurs because injecting water into the combustion process adds additional mass to the airflow without significantly increasing its volume.

As water vaporizes, it absorbs heat from the combustion gases, which can lower the overall temperature of the exhaust gases. The reduction in temperature can enhance the density of the air entering the combustion chamber. The increase in air density improves the engine's performance by allowing more air (and subsequently more fuel) to enter the combustion chamber. This effect can lead to a more efficient combustion process and potentially increased power output from the engine.

The dynamics of how air behaves with the addition of water and the thermodynamic principles involved in gas turbine operations under such conditions support the understanding that air density is increased rather than decreased or unchanged.