Off design performance of gte

[Adel2811]

Hey every body, I need to ask you about the difference between off design performance of gas turbine engine and the design point performance of gas turbine engine ?
Thanks.

 

[etudiant]

The usual measure is specific fuel consumption, ie lbs of fuel per lbs of thrust per hour.
Jet engines usually have a takeoff power rating which may be 5-8x their cruise power rating. while industrial power generating gas turbines are usually designed for one power level. Usually the sfc increases both above and below the design power level. Gas turbines are quite a bit more challenging to modulate than piston engines and the current reliable performance over a wide power range reflects decades of hard work.