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Post by pitciblackscotland on Apr 11, 2023 8:49:40 GMT -5
Hi John, that's some interesting mods to the flametube, let's hope this will give you some results your looking for. LOL sounds like I'm doing several jobs just like what you are doing John Cheers, Mark.
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Post by racket on Apr 11, 2023 16:13:06 GMT -5
Hi Mark
LOL , plenty of time to cleanup once everythings back together :-)
Nice cool morning here , good for getting into the shed for some machining of the diffuser .
Cheers John
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Post by finiteparts on Apr 16, 2023 14:17:49 GMT -5
John, Nice modifications. Just curious if you plan to cant/rotate the injectors or are you planning to use the axially discharging vaporizers? I think the primary benefit of the rotating combustor concept is that there is a relative increase in gas path length from the fuel droplet perspective. Just curious, Chris
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Post by racket on Apr 16, 2023 16:29:39 GMT -5
Hi Chris
I'll be using the original vapouriser tubes as they do a good job , the air injection tubes should produce the swirl as well as keeping the front wall a bit cooler as the 11.5 mm bores will be discharging a pretty solid slug of air at close range onto the wall , my original system with the thimbles producesd acceptable combustion in my short flametube , but the front wall suffered , hopefully this new arrangement might take care of things
LOL, we'll find out I guess :-)
I'm currently adding swirl vanes downstream of the A/B injectors after reading through that Link I posted .
Cheers John
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Post by racket on Apr 16, 2023 20:16:33 GMT -5
Hi Guys Afterburner mods Swirl vanes added to produce , hopefully, better mixing of fuel and air in the A/B and to improve lightoff, which following the addition of the fairing between fuel sprayer and turb exducer hub , wasn't as good as previously . Because of my severe turb exducer clipping , 45+ degrees at tip , the gases exit axially and at greater velocity than with an unclipped wheel , the usual bit of swirl downstream of an unclipped turb wheel provides the necessary swirl within the A/B ......................heh heh , thats my theory anyway Cheers John
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Post by racket on Apr 22, 2023 20:49:55 GMT -5
Hi Guys Bit more , .....decided to add a larger diameter fuel sprayer in the A/B , so scrounged around through my boxes of tubing bits and found some old 1/4"OD stainless tubing from my PJ experiments and made up the necessary ring , then TIG welded it to the original 3/8"OD delivery tubing , what a crap job . Drilled a dozen 1.1mm dia holes in it , 9 on the outer side and 3 on the inner side , gave it a flow test using the garden hose which flowed 9 lpm through it , so my 6 lpm fuel flow should be OK at a lower pressure I'm getting bored waiting for the turbine wheel to arrive , can't find anymore to do on the engine until it arrives . Cheers John
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ripp
Veteran Member
I'm sorry, I don't speak english, so I torment you (and myself) with a translation program,Sorry
Joined: January 2013
Posts: 236
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Post by ripp on Apr 23, 2023 4:44:02 GMT -5
"so back to deepening the diffuser channels tomorrow"
Hi John,
what have you changed in your engine now?
can you post some photos?
thanks Ralph
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Post by racket on Apr 23, 2023 17:05:27 GMT -5
Hi Ralph
Starting at the front , I've modified the IGV stator by reducing the deflection from ~45 degrees to ~20 degrees , to offset any problems with extra mass flow the surge slot has been widened from ~5 mm to 7.25 mm , ~44% increase in area , the new area represents ~23-25% of inducer area , which from researching the issue is whats required .
The diffuser channel depth needed increasing , the guys on the GTBA noticed that my area across the pinched vaneless space wasn't producing diffusion , I had problems with installing the new compressor wheel and getting it to align with things , my compromises weren't very good :-( .................an increase in channel depth from 7.5 to 8.5 mm produced some diffusion ..
Then we come to the flametube which caused my turbine wheel failure , the front wall was cut out and replaced , 18 X 1/2"OD air jets were installed in the outer wall to provide the Primary air along with 18 X 6 mm hole in the inner wall .
The shaft tunnel has had a ceramic blanket and metal shroud fitted to reduce heating of the shaft tunnel from radiated heat from the flametube .
NGV , vanes have been "repaired?? " and the throat area reduced from ~12 mm to 11mm to better handle my higher pressure gases .
Then theres the afterburner mods to improve combustion within it .
So a fair few mods , will post more pics :-)
Cheers John
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Post by racket on Apr 23, 2023 20:05:22 GMT -5
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ripp
Veteran Member
I'm sorry, I don't speak english, so I torment you (and myself) with a translation program,Sorry
Joined: January 2013
Posts: 236
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Post by ripp on Apr 25, 2023 14:41:06 GMT -5
Hi John,
thanks for the pics!
Cheers Ralph
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Post by racket on May 16, 2023 2:24:32 GMT -5
Hi Guys
Rotor is at the balancers , exducer clipped back to 45 degrees same as previous wheel, hopefully making noise before the end of the month
Cheers John
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Post by andym on May 17, 2023 1:41:59 GMT -5
Hi Guys Rotor is at the balancers , exducer clipped back to 45 degrees same as previous wheel, hopefully making noise before the end of the month Cheers John Thants wonderful new.... :-)
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Post by racket on May 26, 2023 4:08:42 GMT -5
Hi Andy
Rotor back home , assembly tomorrow :-)
Cheers John
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Post by andym on May 27, 2023 1:18:15 GMT -5
Hi Andy Rotor back home , assembly tomorrow :-) Cheers John Wonderful..... party time soon then
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Post by racket on May 27, 2023 2:35:09 GMT -5
Hi Andy
Hopefully .
She's back on the teststand , just need to hook up ancillaries tomorrow :-)
Cheers John
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