turbomarc
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Joined: May 2015
Posts: 56
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Post by turbomarc on Jun 1, 2015 6:11:15 GMT -5
I have nothing to contribute to this other than, that's a slick unit, I like the way it is packaged, very cool.
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on Jun 1, 2015 6:04:14 GMT -5
Here's a bit better pic of it all together (prior to painting the oil tank and combustion chamber) As for the extreme temps, this was after about 3 minutes of running the other night, yeah, there is a weird hot spot about the size of a ten cent piece on the collector and even the exhaust housing was starting to get a slight cherry glow.
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on Jun 1, 2015 5:56:56 GMT -5
Hi Marc Theres a couple of things to mention .......... Firstly the fuel injector , too many holes and too big of holes for your sized turbo , this will result in a core of LPG going down the centre of the flametube surrounded by your air resulting in poor combustion until the fuel reaches the tertiary zone where the larger wall holes will penetrate far enough to breakup the LPG core , the air through the smaller Primary Zone wall holes will only penetrate a limited distance into the flametube . Change the fuel injector to one with 6 X 1mm dia radial holes 60 degrees apart around the tube ( end of tube sealed) , the smaller holes and limited number will require a much higher pressure drop across the holes resulting in a high velocity fuel stream that will extend out to, and mix with, the air coming thru the wall holes, position the fuel injection holes opposite the top row of primary zone holes . Secondly , the outlet of your flametube , does it sit on the domed end of the outer can...............or is there a gap ?? All air should go through wall holes for accurate distribution in the correct ratio of ~30% to Primary , 20% to Secondary and 50% to Tertiary main dilution holes . Thirdly , we need a "funnel" between flametube end cross sectional area and entry duct into the turb scroll , if you are only using the domed end of the "fire extinguisher" as your "funnel" there could be a vena contracta ( en.wikipedia.org/wiki/Vena_contracta ) developing , this will put extra backpressure on the compressor resulting in a reduction in mass flow and possibly surge along with increased turbine temperatures . Fourthly , your temperatures are too high , so run the engine without any restriction downstream of the turbine wheel , so no jet nozzle at this early stage until you get those temps under control. Fifthly , what are the comp and turb wheel dimensions , also the turb scroll A/R , there could be a mismatch of sizes that is causing some of those temperature problems. Currently the engine is running , so the hard part is over , just a bit of minor tuning required Cheers John Firstly, Fuel rail: Yes i was made aware of that when i had a chat with Brett "Smithy" yesterday, not only the hole sizing and the amount of them, but the fact they are before the primary, he mentioned the hex nut with 6x1mm holes would be a improvement, but to also have the holes located between the primary and the secondary. Secondly, Flame Tube: Yeah, you caught me out, i didn't even check it sealed till it was too late, I think there is about 2-3mm gap in one or two spots, but I thought i would press on and see if it would fire, have been thinking, maybe get the MIG out build up the end of it, and do the old back and forth, test fit, grind, test fit, weld, until i have it sorted as best as possible, or worst case, just build a new combustion chamber and use my current flame tube with it. Could the extra air bypassing the flame tube be a reason for it running lean thus creating higher temperatures? As for the hole sizing, i used JetSpecs, Flame Tube / Combustor Calculator. Thirdly, Combustion chamber: Yes, I am using the dome as my funnel, that was one of the main reasons i used it, thought it would be an ideal solution, but after reading about Vena Contracta, i can see now, how it wouldn't be a best option for smooth air flow. Fourth, Nozzle: Makes total sense, will lop it off with the grinder and see how it goes. Fifth, Sizing, i can't recall the rear wheel size off the top of my head, but my compressor wheel is 60mm and the exhaust housing a/r is .63 Hopefully this should give you a fair idea of where i am at, please keep in mind there was very minimal research done, the only real references i went off where some info a bloke by the name of Colin Furze posted on youtube after he built one with the purpose of using the afterburner to cook snags!?!?, and JetSpecs. One other thing, i have a boost/pressure gauge connected to the outlet of the compressor housing, and i am curious what should i be seeing at idle, and where is a safe pressure to stop adding fuel? Well, so far it looks like i've got some tasks to knock over once i get some more free time, John, thank you for the tips, will report back in the next couple weeks when i get a chance to get these done Cheers, Marc.
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on Jun 1, 2015 0:05:15 GMT -5
No we haven't met, I shot you a email or two a couple years back in regards to getting argon for the TIG.
Plus every now and then I would stumble across your blog/Web page.
Cheers, Marc.
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on May 31, 2015 22:44:55 GMT -5
Cheers enginewhisperer, just curious the name rings a bell are you based up around Hornsby by any chance?? Pitchblackscotland, yes I know the flame tube is "heavy duty" But I try my best to make use of as many parts, materials I have on hand, as you can see with the conrods for the oil tank mounts. This is the first video I made once it was running, this was the second time it had started, as you can tell by me being pretty edgy when giving it some throttle :lol: But for some reason this is the only video where it's had flames coming out when more throttle is applied, any thoughts?? youtu.be/_oHeoZ656aoThis was a couple of days later, can see that fuel rail getting eaten up, thus the glorious green copper flame at the start. youtu.be/BMUSMQLH9vsCheers, Marc.
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on May 31, 2015 21:20:49 GMT -5
Don't know about that, you guys must have some great mates rates to use some of those HUGE frame turbos.
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on May 31, 2015 21:15:49 GMT -5
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on May 31, 2015 21:15:02 GMT -5
Hi, New to the forums, and gas turbines for that instance, zero experience, keen for your feedback as to where I can improve. For the longest time since I first seen a video of some dude that turned an old turbo into a gas turbine engine I've wanted to do one, all that usually came from it was alot of procrastinating, or not having the time to follow it through. Got a nasty eBay t04 I picked up for cheap collecting dust, so I used that, along with whatever else I could find laying around, powersteering pump, Holden 253 rods, an old fire extinguisher, some gauges I had left over from the last car, some v6 commodore coil packs and a jacobs ladder kit from jaycar.
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on May 31, 2015 5:39:13 GMT -5
Hi John,
Yeah not wrong about Brett, was happy enough to have a chat with me and pointed out a couple of things to help improve on my current setup.
I can see this snowballing from a project that was done just to tick a box, and say "yup, done that", to a possibly expensive hobby.
Cheers, Marc.
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turbomarc
Junior Member
Joined: May 2015
Posts: 56
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Post by turbomarc on May 31, 2015 2:55:02 GMT -5
Hey,
Just joined up, was pointed in this direction today after meeting a bloke with RC Jet dragster, as well as a mental go kart that is powered by a turbo large enough to inhale small children.
I recently finished my first gas turbine build using a T04 turbo, keen to learn more.
Cheers, Marc.
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