Which of the following influences the operation of an automatic fuel control unit on a turbojet engine?
- Exhaust gas temperature.
- Mixture control position.
- Burner pressure.
Explanation
An automatic (hydromechanical) fuel control schedules fuel as a function of engine operating parameters; burner (compressor delivery) pressure is the key signal, because it represents the mass of air being handled and lets the unit set a fuel flow that keeps the fuel/air ratio correct. Mixture controls belong to piston engines, not turbines.
deri asking:
If combustion occurs at CONSTANT pressure, does anyone know how the FCU can be "influenced" by burner pressure??
Community Comments (3)
J
JD2016 Posts: 54 25.03.2017 / 13:21
Maybe because the constant pressure you are thinking of, is the pressure in the Brayton Cycle which is the air or gas (working fluid) pressure, whereas the burner pressure is the fuel pressure at the burner? Maybe I'm wrong - it is a guess.
A
avionics Posts: 9 25.03.2017 / 18:26
rolls royce the jet engine.fuel system.page 10-7, fig 10-9 there is a control of fuel flow regulation which is influence by the compressor delivery pressure. ASU bypass or VMO capsule movement.
R
RiccardoPetre Posts: 2 09.05.2019 / 01:16
i think the question is wrong
Please Sign In to post a comment.