What is the effect of the atomizing air on the gas turbine performance?

Atomizing air increase the fuel combustion efficiency and then decrees the smoke inside the c. chambers and that lead to increase (enhance) the turbine efficiency.

It should be atomizing the fuel for mixture with high pressure air to enhance more combustion.

The better we atomize the air with fuel, the higher power we get with lesser thermal losses. More atomized air ensures a higher combustion efficiency and lead to a higher thermal efficiency. 

Decerease smoke on combustion chambers

Increase efficiency of combustion

Increase efficiency oftthe turbine as a result.

Atomize air is required in turbine if oil is to be use or burn,this would reduce the oil to very fine droplet,with the presence of purge air the the oil fine droplet could be blow through the nozzle and also clean the oil.