Colin Heath
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Joined: January 2020
Posts: 77
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Post by Colin Heath on Jan 11, 2020 8:41:41 GMT -5
Brilliant! That's really helpful and helps me get a feel for scale and layout. Mine will be turbo shaft and will be mounted in front as my mower has good space there. I like the idea of the small engine for auxiliary, I have one of those very units in my shed. Thats a seriously big turbo as well! Did you get it running and if so how was she? |
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Colin Heath
Junior Member
Joined: January 2020
Posts: 77
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Post by Colin Heath on Jan 11, 2020 10:20:55 GMT -5
Here is a picture of the tractor with our grandson on it. I bought this a year ago meaning to put a bike engine on it but the turbine should be much more fun   |
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Post by pitciblackscotland on Jan 11, 2020 18:50:06 GMT -5
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Colin Heath
Junior Member
Joined: January 2020
Posts: 77
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Post by Colin Heath on Jan 12, 2020 3:38:14 GMT -5
That is a big lump when viewed against a standard turbo! Thanks for links to those vids, it’s all wetting the appetite. Just need to resist the urge to plough on (pun not intended) and get design right first. |
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Colin Heath
Junior Member
Joined: January 2020
Posts: 77
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Post by Colin Heath on Jan 12, 2020 13:45:28 GMT -5
I need to decide on fuel injection type so I can then start looking at flame tube design (or should I say ask others to help me look at it).
I see from reading here that there is the method of direct spray atomising the fuel like in a diesel injection system or the other which sounds like the fuel is vaporised by heat through a tube which acts as heat exchanger, I think.
I’m assuming the vaporising tubes is easier to get working as I see on Andy’s money pit thread they are trying an injection type to improve.
Can I start and run on kerosene without vaporising tubes but with different injectors?
I’m assuming a smaller mist for start and then a much larger nozzle for running but I know too well where assumption gets me haha.
Ignition system I can design to be as powerful as required as I still have lots of old High Voltage gear here from my past hobbies and can produce sparks that will reach flame tube wall if needed 😂
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Post by slittlewing on Jan 12, 2020 15:09:28 GMT -5
The easier method is a single central spray using an oil burner nozzle (monarch or danfoss, available in many different flow rates).
The evap tubes are much harder to make using a manifold with loads of needles and heater tubes, normally used for engines with full axial combustor like johanssons/rackets/Andys.
The single oil burner nozzle is normally used for turbo based setups with separate combustor. You can power it with 2–>10bar fuel pump. Or hydraulic pump with more pressure and smaller nozzle will give better atomisation. Controlling the delivery pressure will vary the fuel flow from starting to running to high power (no need for two nozzles).
Cheers
Scott
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Post by racket on Jan 12, 2020 15:17:55 GMT -5
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Colin Heath
Junior Member
Joined: January 2020
Posts: 77
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Post by Colin Heath on Jan 12, 2020 15:23:05 GMT -5
The easier method is a single central spray using an oil burner nozzle (monarch or danfoss, available in many different flow rates). The evap tubes are much harder to make using a manifold with loads of needles and heater tubes, normally used for engines with full axial combustor like johanssons/rackets/Andys. The single oil burner nozzle is normally used for turbo based setups with separate combustor. You can power it with 2–>10bar fuel pump. Or hydraulic pump with more pressure and smaller nozzle will give better atomisation. Controlling the delivery pressure will vary the fuel flow from starting to running to high power (no need for two nozzles). Cheers Scott Thats great news and sounds a lot simpler than what i had in my head. Using the oil burner nozzles makes lots of sense as there is a huge amount of work goes into nozzle design, R&D etc. Thanks for the help Scott. I have read a few threads where John has advised 2 rows of primary holes with larger holes on second row where spray is directed. I will draw up an initial design for discussion and take it from there. I will also have a scan around here and look for some detail in the threads about the pumps etc. I have seen few mention the small gear pumps and driven with a brushless RC motor. Cheers, Colin |
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Colin Heath
Junior Member
Joined: January 2020
Posts: 77
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Post by Colin Heath on Jan 12, 2020 15:29:19 GMT -5
What a great solution as it even has strainer and oil return bypass to ensure correct flow. Thanks for the help John. I will go and do some further reading and come up with a few design ideas from what others have built and is tried / tested. |
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Post by racket on Jan 12, 2020 15:44:00 GMT -5
Hi Colin The combustor in my TV84 used a single spray nozzle ibb.co/zbJHGX3 , there were "additions" to the basic combustor like the extra air delivery tube to the head and a bleed air valve , both just experiments that didn't achieve anything :-( Cheers John |
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Colin Heath
Junior Member
Joined: January 2020
Posts: 77
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Post by Colin Heath on Jan 12, 2020 16:00:09 GMT -5
Hi Colin The combustor in my TV84 used a single spray nozzle ibb.co/zbJHGX3 , there were "additions" to the basic combustor like the extra air delivery tube to the head and a bleed air valve , both just experiments that didn't achieve anything :-( Cheers John Thanks John, I see you have some slots in top of flame tube to deliver air also. Is that to aid in cooling like I often see you suggest, or to help with fuel/air ratio? Almost looks like guide vanes to create swirl. On further study it looks like the very small holes in dome are cooling so assuming the mentioned slots / vanes are for something else. EDIT: Not paying attention and see they must have been for the air addition on the top. Throughly enjoying the learning curve of this all being so steep. Takes me back to when I first started with high voltage and tesla coils Cheers, Colin |
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Post by racket on Jan 12, 2020 19:48:31 GMT -5
Hi Colin
Yep , the small holes in the cap are for both combustion air as well as keeping things cool , the swirl vane set surrounding the spray nozzle is for supplying combustion air as well as aiding in the mixing of fuel and air , I basically just copied a standard can , theres louvers at the various segments in the flametube to provide cooling air for the wall, there needed to be more in the Primary Zone as it suffered a bit .
LOL..............you'll never stop learning new stuff with this hobby , 30 years down the track and its still throwing up new problems for me to solve .
Cheers
John
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Colin Heath
Junior Member
Joined: January 2020
Posts: 77
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Post by Colin Heath on Jan 13, 2020 13:31:06 GMT -5
Hi Colin Yep , the small holes in the cap are for both combustion air as well as keeping things cool , the swirl vane set surrounding the spray nozzle is for supplying combustion air as well as aiding in the mixing of fuel and air , I basically just copied a standard can , theres louvers at the various segments in the flametube to provide cooling air for the wall, there needed to be more in the Primary Zone as it suffered a bit . LOL..............you'll never stop learning new stuff with this hobby , 30 years down the track and its still throwing up new problems for me to solve . Cheers John Cheers John, Looking forward to more learning |
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Colin Heath
Junior Member
Joined: January 2020
Posts: 77
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Post by Colin Heath on Jan 13, 2020 13:40:54 GMT -5
So the turbo arrived today which marks the start of the fun  It's all in one piece although the radial play is huge. I expected some due to fact it's a bushed unit rather than ball bearing and also a little bit more due to it being cheap as chips, but it's all over the shop! Here is video of play. The turbine doesn't quite touch but not far off! I'm assuming this will improve in operation though when oil film running through bushes. A couple of pictures also. Finally picture of flange I will cut out tomorrow on the CNC Plasma from 10mm stainless.    |
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Post by racket on Jan 13, 2020 14:43:01 GMT -5
Perfectly OK , they're assembled dry to make sure the wheels don't hit the housings , they need a lot of bearing clearance otherwise we couldn't get the required oil flow for cooling the bearings or sufficient control of rotor dynamics which can be very complex ..................shove some oil in it and alls well :-)
Yep , keep flanges thick , especially on the hot bits
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