Controlling Fuel Flow in a Jet

Jet fuel nozzles, ignitors, combustors, fuel lines, a look inside the combustor of a real turbojet engine, and I try to explain how it all works.

Category:

Autos & Vehicles

Tags:

• jet
• turbine
• engine
• compressor
• combustor
• ignitor
• nozzle
• fuel
• flow
• power
• control
• Orenda
• Type14
• turbojet
• AVRO
• CF100
• Canuck
• fsj
• joljbc

[rschulemann]

Big fan with a quick question. Since these are aero-derivative engines, is the gearbox used for power takeoff? What changes, if any, are made to the drivetrain?

[AgentJayZ]

@rschulemann The radial drive shaft is ised to supply power to the gearbox to drive the accessories. The difference in industrial engines is that there are less accessories driven.

This engine produces about 10 thousand Hp.. in the form of hot, high velocity gases exiting the engine... to be sent through a separate power turbine, which then turns a shaft.

[elcuervo1984]

Thanks AgentJayZ, your videos are amazing... I'm working on a power plant where we have 190MW gas turbines for electric generation, once we got problems with icing in the two first stages of the axial flow compressor, apparently the ice grew up as much as it could touch the rotor blade tip at 3600RPMs deforming it, then the discharge pressure went down and so did the power output... I would like to know if you had have same problem in aircraft engines?

[AgentJayZ]

@elcuervo1984 Occasionally we experience icing of the inlet during our testing. I've only seen ice build up on the leading edges of the struts in the front frame. This happens at just above freezing when the humidity is high.

On days like that when we are having a test, we place one person where they can watch for ice in the inlet, and if they see it, we stop the test. The reason is the engines we work on are not equipped with anti-icing capability.

[pjvenda]

I'm sure there's a world of engineering into fuel nozzles, shaping of the combustors and even more onto fuel mappings. But it is funny that it kind of works like a tap: if you want more, just open the tap more :) Any clues on a typical mapping of power vs fuel pressure? is it even close to proportional or much more esoteric?

[AgentJayZ]

@pjvenda I've just been doing some reading on combustor design, and as always, it's a bit more complicated than I present in this quick, easy video.

Although there is no control for fuel-air ratio in a jet engine, the ratio in the combustion zone does change on its own. Because of the interaction between fuel spray patterns at differing fuel pressures, and air density at different compressor discharge pressures, the air-fuel ratio changes from lean at start to rich at full power.

[alanhigh]

These are the best videos on the internet.

[LarryCanFly]

AgentJayZ is the greatest turbine teacher.

[buffplums]

Very interesting thank you!

[911mastermind]

@AgentJayZ which gives jet engine more efficiency, lean fuel or rich fuel mix if ur at optimum power or cruise power or wat ever u guys call it....? ?

and generally the air/fuel ratio depends on the bypass ratio or something?

[Tomasu321]

@AgentJayZ I get positively giddy whenever you post a new video!, absolutely fantastic informative and interesting. Really makes me want to work with this.

[plasticspastic201]

@alanhigh yeh excellent channel.

cheers