miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Sept 15, 2023 13:44:55 GMT -5
This will make life of many DIY jet enthusiasts way more easier, very reasonable pricing too! Can you post some screenshots of the current software?
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Jun 18, 2023 17:09:55 GMT -5
What material have you used to build your turbine wheel? Are the blades welded onto the hub? Since this compressor wheel seems pretty small size it needs a relatively high rpm to operate, which you probably knew, but after zooming into your picture I have my doubts that turbine wheel would survive the design rpm.. Be careful with that and don't stand anywhere close to turbine exit or side of the turbine...
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Jun 16, 2023 15:23:20 GMT -5
Ihan oikein päätelty sijainnin mukaan Your setup is very unlike to work with that sort of fuel delivery if you used it as is, you need a radial spray injector something like this: hosting.photobucket.com/albums/x281/mice325/Project%20Jatkettu/WP_002239_zps8d90877f.jpgAlso get rid of that pressure regulator, most of them limit the flow too much or the safety feature cuts off the gas when it sees "backpressure" from the combustor. Try these two tips first before making any further changes.
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Jun 16, 2023 14:47:47 GMT -5
That's an enormous size combustor for a turbo that small, maybe lack of air mixing up with fuel? How's the fuel nozzle? More pictures needed of the internals..
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on May 17, 2023 14:41:39 GMT -5
Combustor cap where the injector is located usually runs very hot, without a layer of cooling air around the injector as in simplest form of combustor it can glow orange, a regular fuel injector would melt. If you can choose, get a stainless oil burner nozzle as even brass nozzles can melt in a bad setup. Secondly car fuel injectors have a very narrow spray angle, 80 or 90 degree spray cone as on oil burner nozzles is a lot more ideal for these combustors.
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Apr 5, 2023 16:30:42 GMT -5
Initially I drew up and considered having a rear mounted flametube so that the standard turbo shaft tunnel could be used , but due to the 128 mm turb exducer , the outer can diameter was going to become too large once allowances were made for flametube cross sectional area and flow space around it , so I resorted to my usual practice of making my own shaft tunnel and having the flametube between the wheels Since front of the flametube and directing high speed air from comp diffusor seems generally problematic with these micro turbine style engines, would it make sense to route air externally past the flametube to hot end first and then turn it back? I could imagine better and more stable air distribution for the front and inner wall, it would also allow playing with the cross sectional areas to slow down the flow even more at tight turns if needed. Obviously will add complexity and size too.
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Jan 18, 2023 18:01:49 GMT -5
One night I gave a thought for what I already have and what's needed, I was reading my previous posts and wanted to confirm I'm on the right track.
Oil system should be bulletproof on this one, oil pump I bought earlier is 3cc/rev hydraulic pump. I found a HX82 manual online which tells requirements for oil pressure and flow:
12. Oil pressure of 150 kPa (20 lbf/in2) must show at the oil inlet within 3 - 4 seconds of engine firing to
prevent damage to turbocharger bearing system. A flexible supply pipe is recommended. Recommended
oil pressure at full load/ rated speed is 300 kPa (44 lbf/in2) although 600 kPa (88 lbf/in2) is permitted
during cold start up. Under idling conditions pressure should not fall below 70 kPa (10 lbf/in2).
14. Recommended oil flows for the turbochargers are 3.5 litre/min at idleand a minimum of 6 litre/min
above maximum torque speed.
To meet the 6L/min flow I need to spin this 3cc/rev pump at 2000rpm and as I want to have plenty margin, say another 50%, I set motor requirement at 3000rpm. I had a 6368 190KV motor added on my shopping cart since before, but found another 6384 150KV motor which should provide a bit more oomph. The seller also offered customization service for these motors, I calculated that 100KV motor should do the job easily at nominal 36V and even with "empty" 36V 10S lipo battery it should meet the requirement without dropping oil pressure. Of course other safety parameters and switches will be added so that there will be no situation with no oiling. Comments?
As a starter motor for the turbine 5692 980KV unit at 36V was considered and I think that's still the best I can find, 35000rpm at nominal voltage, probably even more with full battery pack and a capable controller.
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Jan 15, 2023 10:10:01 GMT -5
Unfortunately no news on this, we've been busy doing parts as a subcontractor and our own automotive components, family got bigger and time for hobbies has been limited for a few years now Couple of project cars need to be finished first and who knows what's next.. I've had thoughts of getting a vertical CNC mill after the CNC turning center has been paid and if we then have bigger facilities. Already asked a quote for this machine which would probably suit well for our purposes: en.dmgmori.com/products/machines/milling/vertical-milling/cmx-v/cmx-600-v
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Jan 8, 2023 17:14:39 GMT -5
0W16 is very low viscosity oil and as it gets hot pretty quickly your pump does not have enough flow capability to maintain higher pressure. EFI fuel pump as seen on your setup is not recommended for such use either. Switch to let's say 10W30 oil which can stand the heat better and upgrade your oil pump to something else if cannot cope with it.
The pop which caused the intake tube to come off seemed more like "flameout" and re-ignition to me?
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Oct 27, 2022 13:50:50 GMT -5
Pick one with single entry turbine housing if possible, divided housing is a "compromise" for flow and hot spot on the divider, but surely people have managed to use them successfully too. HX55 and GT37s are probably easiest to find spares.
Correct, 20% rule is between comp inlet and turbine outlet, turbine being the bigger one.
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Sept 27, 2022 16:06:42 GMT -5
So in other words you're not building a gas turbine but a gas fed fan that will spin and produce heat. I have no doubts you could achieve your goals with this design, I've seen worse on YouTube! Like John said, even a slightest amount of produced exhaust that can be directed through the exhaust wheel will probably make it spin if mounted on responsive enough bearings.
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Sept 18, 2022 13:57:30 GMT -5
What about the mighty Holset HT100 turbo? I believe these are still in production, used in big Cummins engines. Standard turbocharger layout, nothing fancy or too exotic and easily available.
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Aug 26, 2022 14:12:39 GMT -5
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Aug 4, 2022 12:32:02 GMT -5
The pump head itself produces easy 8bar at cold oil temps and at running temps plenty enough for any DIY turbines, its just the electronics of the pump that sucks.
|
|
miuge
Veteran Member
Joined: March 2014
Posts: 199
|
Post by miuge on Aug 3, 2022 14:25:19 GMT -5
We used a similar pump on our build and it had problems with managing heat. I think there was a heat safety switch inside which turned the pump off and after we took it off the plastic cap where the brushes are mounted melted. If you think of making a metal cap remember you need to have some sort of insulation between the brushes and the cap, no electricity can run thru the brushes to the cap via screws or such. Secondly the pump flows a bit too much oil for a medium sized turbo I think, we had it coupled to a BW S257 turbo and had to by-pass some oil, we thought of turning down the gears, but never tried.
Nowadays I think there's much more reasonable solutions such as hydraulic gear pumps coupled to a separate motor with a speed controller. See user 'andym' previous posts for reference.
|
|