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Post by madpatty on Sept 4, 2017 11:10:39 GMT -5
[/quote]So they simply used a venturi port for water injection? Then my spray nozzle is really high tech, I was worried that I would have to use multiple smaller ones to get the droplet size down to avoid damage to the compressor leading edges. (The ABB compressor might be made out of a better material than cast aluminum but still...)[/quote]
Hi Anders,
Congrats on the successful run.
As far as the material of the compressor wheel is concerned, I don't think it is any better material than just a milled out piece from solid aluminium.
Cheers.
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Post by Johansson on Sept 4, 2017 13:48:41 GMT -5
Hi Anders A top 10 finisher :-) I've enjoyed your ride a dozen times , LOL...keep going back for just one more . Acceleration times were very good for a single speed gearbox , 0 to 100 kph in ~4 seconds , only another 3 secs to 150 , so a tad over 7 secs for zero to 100 MPH , not bad ................. acceleration still fairly consistent with only another 4 secs from 150 to 200 kph and only 5 secs more to 250 , still pulling strong , then as your terminal velocity was approaching she slowed down taking another 9 secs for the 250 to 300 ...............looks like gearing was just about spot on . But those temperatures are still a "mystery" to me ............its a wonder theres any blades left on either the gas producer or freepower wheels , T I Ts would have had to be ~1,250 deg C :-( A bit of a glow for the interstage duct would be OK , if ~900 C for a T I T , say 750 C interstage , this would give some "colour" and certainly leave the freepower with a nice red glow at the end of a run if ~600 C for the exhaust temp. Looking forward to seeing what she looks like inside . Cheers John Actually the bike was geared to reach 30.000 freepower rpm at around 330-340km/h so it was a bit tall just to play on the safe side. I´d rather start at that end and increase the freepower revs once I have bottomed out JU-02, the one thing I don´t want to experience is a gearbox failure at 300++km/h... The exhaust temps are a true mystery, I´ve changed both temp gauges and locations numerous times over the years and I still get impossibly high temp readings. It doesen´t really matter now, JU-02 shows much more reasonable temps. After some kind of drunken havoc at the after One Mile party (I wasn´t there so I don´t know what happened) the arrangers have decided that there won´t be a race next year, very sad but there are more races around Scandinavia so I can still run the bike even if I have to travel a bit longer. Since JU-02 ran perfectly up to 2 bar P2 I am thinking that if the engine keep the temps reasonable up to full RPM I will end the tests and focus on getting the engine installed in the bike so I can have the bike ready by next summer. Knowing how the JU-01 engine performed at only 2.3-2.4bar, how hard do you think that I need to run JU-02 to get the same kind of speeds out of the bike? Congrats, Anders! What a run! Thanks! Nice Anders you got it, Im very happy for you! Thank you Sven! Hi Anders, When you get the JU-02 installed put the bike on a dyno. It would be awesome to see how the JU-02 produces its power curve. I am not sure any dyno owner would like to test a turbine bike, it isn´t easy to get the exhaust jet out of the dyno room. Just ask Andrew (jettoymaker)... Hi Anders, Congrats on the successful run. As far as the material of the compressor wheel is concerned, I don't think it is any better material than just a milled out piece from solid aluminium. Cheers. Titanium is a lot better.  |
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Post by racket on Sept 4, 2017 15:43:32 GMT -5
Hi Anders
Even at your current P2 the JU-02 should be supplying ~20% more air just from the larger inducer area , but that will increase another 10% or so with the higher P2s , so just from airflow alone theres ~30% increase , but the higher P2s will increase the pressures going into the freepower resulting in higher gas speeds and deflection , so more percentages of increase :-)
Your current gearing will be fine for a bit longer .
I'd be seriously thinking about a "bypass" at the interstage if you find the temps are too high at low speeds .
Cheers
John
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Post by racket on Sept 4, 2017 23:55:20 GMT -5
Hi Anders
A thought ..............lets assume your ITT is reading correctly , say ~1100 deg C - 1373 K instead of ~750 C - 1023K , 1373/1023 = 1.34 , your gases will be 34% less dense than they should be , that will restrict/lower the mass flow through a choked gasifier NGV or whatever downstream , the gas velocities will be higher and might knock off say 20% of the "losses" , but overall you'll probably have less power than if running the cooler temps with greater mass flow ..................your "Corrected Flow" drops off with excessive temps .
Could there be a "restriction" downstream of the gas producer that is causing the excessive temps , the freepower wheel doesn't seem to make much difference whether stationary or spinning at high rpm , the only other possibility is the freepower NGV or exhaust duct which may need to be more "aerodynamic"
Cheers
John
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Post by enginewhisperer on Sept 5, 2017 1:08:06 GMT -5
Can't get enough of the flyby sound |
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CH3NO2
Senior Member
Joined: March 2017
Posts: 455 
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Post by CH3NO2 on Sept 5, 2017 5:25:20 GMT -5
Can't get enough of the flyby sound Totally. The best sounding IC reciprocating engine has nothing on a turbine flyby. |
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Chuks
Senior Member
Joined: August 2015
Posts: 498
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Post by Chuks on Sept 5, 2017 6:45:36 GMT -5
Hi Anders,
what a wonderful run, I don't know why but I always focus on the jet sound.
you are a supper role model.
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Post by Johansson on Sept 5, 2017 14:04:07 GMT -5
Hi Anders Even at your current P2 the JU-02 should be supplying ~20% more air just from the larger inducer area , but that will increase another 10% or so with the higher P2s , so just from airflow alone theres ~30% increase , but the higher P2s will increase the pressures going into the freepower resulting in higher gas speeds and deflection , so more percentages of increase :-) Your current gearing will be fine for a bit longer . I'd be seriously thinking about a "bypass" at the interstage if you find the temps are too high at low speeds . Cheers John This sounds absolutely great, I´ll do some more tests at higher P2 just to see that it won´t start behaving strange and get the electric starter fitted. Then I will start installing it in the bike and build the interstage section with the C20 NGV instead of the home made one. I haven´t really decided yet if I will weld the C20 NGV to the interstage or clamp it somehow, welding is easier by far but might induce cracks later on. I´ll consider a bypass if the JU-02 starts to heat up at low speeds when the freepower is installed. Hi Anders A thought ..............lets assume your ITT is reading correctly , say ~1100 deg C - 1373 K instead of ~750 C - 1023K , 1373/1023 = 1.34 , your gases will be 34% less dense than they should be , that will restrict/lower the mass flow through a choked gasifier NGV or whatever downstream , the gas velocities will be higher and might knock off say 20% of the "losses" , but overall you'll probably have less power than if running the cooler temps with greater mass flow ..................your "Corrected Flow" drops off with excessive temps . Could there be a "restriction" downstream of the gas producer that is causing the excessive temps , the freepower wheel doesn't seem to make much difference whether stationary or spinning at high rpm , the only other possibility is the freepower NGV or exhaust duct which may need to be more "aerodynamic" Cheers John There might very well be a restriction downstream JU-01, last year I had to weld several cracks in the freepower NGV so of one or several of the vane welds have cracked again they might have bent and partially blocked the NGV. We´ll soon find out, I will remove the engine from the bike as soon as I get back home from hunting a couple of weeks from now. Cheers! /Anders |
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Post by racket on Sept 5, 2017 17:57:51 GMT -5
Hi Anders
Another reason for the bypass, even if you don't have excessive idling temps, is that it'll keep both turbine wheels "cooler" until you start your run resulting in a bit more time for things to heat up, it'll provide a bit more "safety" buffer as our max design temps are going to be on their limits .
I'd be opting for a "clamped" fit for the freepower NGV , loose enough so that it can expand/contract quicker than the surrounding interstage material, also there might be a need for blocking off some of the passageways in the NGV if we find its too "open" .............it'll depend on gas temps/densities/mass flow etc etc .............so easy removal for mods would be desirable .
Cheers
John
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CH3NO2
Senior Member
Joined: March 2017
Posts: 455
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Post by CH3NO2 on Sept 5, 2017 21:35:02 GMT -5
Hi Anders, In your prior post you mentioned there was some kind of an instability at low RPM when you injected the water/meth. What are your thoughts on how it worked (or didn't work) like it did? Can you describe how it was set up compared to the PDF in your boosting gas turbines thread? Water/meth injection is a subject I will definitely test in my build. jetandturbineowners.proboards.com/thread/889/boosting-gas-turbines-bill-gunstonThanks, Tony |
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Post by racket on Sept 6, 2017 0:38:55 GMT -5
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Post by Johansson on Sept 6, 2017 12:03:31 GMT -5
Hi Anders Another reason for the bypass, even if you don't have excessive idling temps, is that it'll keep both turbine wheels "cooler" until you start your run resulting in a bit more time for things to heat up, it'll provide a bit more "safety" buffer as our max design temps are going to be on their limits . I'd be opting for a "clamped" fit for the freepower NGV , loose enough so that it can expand/contract quicker than the surrounding interstage material, also there might be a need for blocking off some of the passageways in the NGV if we find its too "open" .............it'll depend on gas temps/densities/mass flow etc etc .............so easy removal for mods would be desirable . Cheers John Hi John, I think I will settle with a running temperature that is more "daily driver", I don't like the idea of running on the outmost edge where the turbine wheel is almost at melting temps when I pass the finish line. Clamped it is then, another benefit is that I can get me a spare one that can be easily fitted in case I need to at race day. Cheers! /Anders |
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Post by racket on Sept 6, 2017 17:45:03 GMT -5
Hi Anders
Yep , start with a fully open NGV and see how the temps are , then slowly close off openings to raise the temps to the desired level of ~750-800C for the interstage ......LOL, we'll keep the needle on the gauge ;-)
The static gas pressure in the interstage will keep the NGV forced against its seating so it'll only need a minimal amount of fixings to have it sitting in position and free to "move around" as the temps and expansion dictate , any minor leakage won't affect power output by more than a horsepower at most.
Cheers
John
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Post by Johansson on Sept 7, 2017 1:46:47 GMT -5
Hi Anders, In your prior post you mentioned there was some kind of an instability at low RPM when you injected the water/meth. What are your thoughts on how it worked (or didn't work) like it did? Can you describe how it was set up compared to the PDF in your boosting gas turbines thread? Water/meth injection is a subject I will definitely test in my build. jetandturbineowners.proboards.com/thread/889/boosting-gas-turbines-bill-gunstonThanks, Tony Hi Tony, I don't know if the low boost fluttering I had was caused by the water or something else, the engine "hickuped" a few times during each run for some reason. The setup is a large capacity spray nozzle aiming into the compressor inlet. You can see it in the riding video, I held the throttle pinned throughout the run but the P2 dipped down towards 2 bar a few times. I will have to check if I have a problem with voltage drop when all pumps are working hard, it shouldn't behave like this. Another thing I will try is to change from 5w30 oil to 10w60 and see if the oil pressure stays more constant when the oil starts to heat up, if not I might have to add a separate oil pump for the gearbox lubrication instead of sharing pump with the gas producer. |
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Post by Johansson on Sept 7, 2017 1:54:10 GMT -5
Hi Anders Yep , start with a fully open NGV and see how the temps are , then slowly close off openings to raise the temps to the desired level of ~750-800C for the interstage ......LOL, we'll keep the needle on the gauge ;-) The static gas pressure in the interstage will keep the NGV forced against its seating so it'll only need a minimal amount of fixings to have it sitting in position and free to "move around" as the temps and expansion dictate , any minor leakage won't affect power output by more than a horsepower at most. Cheers John Hi John, That is the plan, first I'd like to see moderate running temps and later I can start blocking off the freepower NGV until I get the best "safe" performance out of the bike. I could make some kind of sliding fit for the C20 NGV and use it as the expansion point for the engine, the I can mount the JU-02 firmly in the chassis. The track gets quite bumpy at speed so it is probably a good thing to have the gas producer secured so it won't jump around and possibly damage the interstage duct. Cheers! /Anders |
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