Fuel Flashcards
Purpose of a fuel system
To supply a precise amount of clean vapor free fuel to the combustion section of the engine,
At a pressure and temperature suitable for efficient atomisation/vaporization
Components in fuel sys [8]
Lp fuel pump Fuel cooled, oil cooler Fuel heater (bleed air) Lp filter Hp pump Hp filter FCU P&D valve
2 types Fuel pump
Constant displacement
Variable displacement
FCU types [3]
Hydromechanical
Hydropneumatic
Electronic
Hydromechanical does..
Computing and fuel metering
FCU parameters [4]
Power lever position
Engine speed
Compressor inlet temp and pressure
Burner / discharge temp and pressure
Outline P&D valve
Pressurises fuel to correct pressure
And dumps fuel on engine shutdown to prevent (hotstarts)
Fuel nozzles types
Atomization
- simplex
- duplex
Vaporization
Outline simplex and duplex
Simplex is primary nozzle for start up (wider spray)
Duplex two nozzles and has a narrower spray