After Burner Design Questions

[thehazard]

Hi there. 

I have recently built the shell of an afterburner based off tech ingredients simplified design in this video: www.youtube.com/watch?v=EP4Hf63zR6w&t=1941s

His video made it look like an after burner only needed a semi sudden increase in the diameter of the tubing. This was to allow for the relatively stable combustion of additional injected fuel. Reading the after-burner section in the diy-turbines thread made me realize that the tech ingredients design might be to simple.

Here are some pictures:







Does this design work or do I have to fix it?

[racket]

Hi

Don't believe anything Tech Ingredients tell you about turbine engines, the know nothing , all they do is repeat info they're stolen from somewhere else :-(

I'll have a look at their design and get back to you .

Cheers
John

[racket]

Hi

Yep , they've overcomplicated things , again , beautiful build quality and presentation as always , BUT !!! :-(

Plus they're barely running at minimal fuel supply, so no way of knowing what will happen at full power .

The sudden expansion afterburner has been around for 50 years apps.dtic.mil/sti/tr/pdf/ADA067277.pdf , the Members on here have been using it for >20 years , check out Andys video www.youtube.com/watch?v=AmMrdlqAEPI&ab_channel=JetEnginesAndyMorris

Cheers
John

[thehazard]

Thanks for the help. It relieves me to hear I don't have to redo the A/B.

Though now that I am thinking about it, I do have one more question regarding A/B design. I intend to have 4 fuel injectors equally spaced around the A/B. Should they be located on the cone immediately after the turbine outtake, or on the cylinder spot maybe a few inches past the cone?

Thanks again for the help.

[racket]

Feed the fuel in as early as possible .

I'm still not certain about your actual A/B construction though , could you post a rough drawing please

[thehazard]

Hi again,

Sorry for not clarifying. My A/B has zero internals and is simply a big tube with cones on it.

Like this:

[racket]

You'll need some form of flameholders in the upstream end of the main tube

[thehazard]

Ok.

Should the flame holders be located before or after fuel injection?

[racket]

After , and far enough rearwards for the fuel to disperse before encountering the flameholder , a few inches at least