GTCP85-98C APU, with afterburner?

[racket]

Their builds are beautifully constructed, no shortage of money spent , but they simply and expertly mouth the words without actually having any experience or knowledge , thats why their turbines have had very poor output results , its one thing to make some noise and flame , its another to produce performance .

[tacobell]

Does anyone happen to have Richard Browns contact info? Email?

When it comes to simple function over performance, how accurate do the ducting sizes have to be? I think that I can figure out the fuel requirement based on stoichiometric value with the available bleed air values from the manual, and maybe cross check them to his engine while scaling the duct. I just wonder how the inside is configured.

What type of ignitor do you think should be used? Automotive park plugs can deal with high pressure from boosted engines, but is it enough?

I like how he made it somewhat modular, can play with the final nozzle size without much trouble. Very clean

[tacobell]

If my math and research are correct, I'll need to flow 0.61 USG/min of fuel, or 2.31L/min. I'm guessing that fuel pressures should be similar to the gas turbine, close to 300psi when loaded up, or min 200psi depending on nozzle and atomization properties?
The bleed air valve is 4", I can neck it down to 3" using common exhaust tube, then when it diverges up to (6-8"?) add fuel, then ignition further down with the flame holder immediately after, and then start converging until we get the desired result. Which, BTW, is what? If this were on the turbine exhaust duct, we'd be watching the EGTs, but that's not as much of a concern, correct? Are we choking it until it stops producing thrust?

Finally, a project that doesn't have any moving parts lol

[racket]

His combustor looks like an old 1950s RR aero one , fuel and ignitor bits do too . .

Your Specs for the bleed air indicate ~2 lbs/sec at 46.5psia - 32 psig , so a combustor for 2 lbs/s at ~3:1 PR , easy, ~1.2 US GPM of fuel :-)

Thats not much different to what I had for my bike jetandturbineowners.proboards.com/thread/1366/tv84-turbine-bike except you need to burn all the oxygen , so more Primary holes and no Tertiary dilution holes .

Ideally air being delivered axially to the fuel nozzle end of the combustor as flametube wall cooling will be important , you need to construct a high pressure afterburner for 30 psi rather than 10 psi which we normally have

Automotive spark plug will work , nozzle throat diameter will be a tad more trial and error as it'll depend on variables like combustion temps and uniformity of density, etc etc , but we should be able to get a ball park figure to start from, probably ~2.5- 2.75 inch dia .

Yep , copy his design , shamelessly :-)

Cheers
John

[tacobell]

Oh I was calculating based on 1 lb/sec air flow, not 2. Thanks for looking at that, I couldn't figure out the PM value for air flow.

When you say build it for 30 psi, you're just referring to it as being made of strong enough materials for that? Or is there a design change?

[racket]

There needs to be a design change from our usual afterburners due to the higher static pressures within , with our normal afterburners they're glowing yellow with the stainless sheeting's tensile strength seriously reduced , but still able to handle the relatively low static pressure within .

Ideally we want the combustion area isolated from the outer shell with relatively cool air/gases between , in your case you can have air at only ~200deg C , similar to how our engines combustors operate with combustion within the flametube , you need a "combustor" rather than an afterburner .

Have a look at these ramjet combustors secwww.jhuapl.edu/techdigest/Content/techdigest/pdf/V13-N01/13-01-Keirsey.pdf

[tacobell]

racket, how are you calculating the 2lb/sec of bleed air flow? Google is letting me down here in trying to convert PM of air to a proper flow unit of measure.

[tacobell]

First time attaching a picture, does it work?  
This is my guess as to what the inside could look like, or how it could work.  Please let me know what you would change.  I've scaled the sizes as well based on the bike's known wheel diameter.

Thanks

[racket]

The Specs you provided gave differing amounts of air flow and pressures depending on other power outputs from the engine , without anything else sucking power all available energy is available for compressing bleed air , 2 lbs/sec to a 3:1 PR is going to require >175 HP.

I'll have a think about your combustor

[jetric]

Hi Tacobell,
I will send you Richard Browns contact number on a private message,

Richard S.

Aug 16, 2024 19:31:59 GMT -5 tacobell said:

Does anyone happen to have Richard Browns contact info? Email?

When it comes to simple function over performance, how accurate do the ducting sizes have to be? I think that I can figure out the fuel requirement based on stoichiometric value with the available bleed air values from the manual, and maybe cross check them to his engine while scaling the duct. I just wonder how the inside is configured.

What type of ignitor do you think should be used? Automotive park plugs can deal with high pressure from boosted engines, but is it enough?

I like how he made it somewhat modular, can play with the final nozzle size without much trouble. Very clean