pulse detonation valveless gasturbine

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leo
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pulse detonation valveless gasturbine

Post by leo » Fri Jun 27, 2008 7:00 pm

Looks like a scam to me
How they want to get any efficiency out of a Pelton shaped turbine wheel

A Detonation Cycle Gas Turbine engine includes a turbine rotor contained within a housing. Exhaust ports of respective valveless combustion chambers located on opposite sides of the rotor direct combustion gasses towards the turbine, which operates in similar fashion to a Pelton Water Wheel.
http://ttengines.com/technology.html

on youtube

http://www.youtube.com/watch?v=yxT93dlMrd0&fmt=18

Zippiot
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Re: pulse detonation valveless gasturbine

Post by Zippiot » Sat Jun 28, 2008 6:22 pm

WOW

want to build....
Sailing Student- How do I know if my life jacket is tight enough?
Me- Can you breathe?
Sailing Student- Yes
Me- Then its too loose!

silvercheck
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Re: pulse detonation valveless gasturbine

Post by silvercheck » Thu Jul 23, 2009 3:34 am

I'd believe it. Look at the water turgo's they have a slot in the pellers so the jet can get in closer to them. When the peller is closer to the jet it works hugly more efficient, the problem with impulse turbines is the peller has to move away. A pulse detonation timed for when the peller is closest should save a lot of fuel. Timeing a pulsejet to a simple turgo would be very easy to build.

ace_fedde
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Re: pulse detonation valveless gasturbine

Post by ace_fedde » Fri Jul 24, 2009 7:24 pm

Here is some more clear movies:
http://ttengines.com/prototypes.html
So it works
leo wrote:Looks like a scam to me
Remarkeble claims about efficiency are always made. Is it real this time? Who knows..

Fedde
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Re: pulse detonation valveless gasturbine

Post by racketmotorman » Sat Jul 25, 2009 11:33 pm

Hi Fedde

Its an updated Holzwarth gas turbine , Holzwarth built a 25 ton version in 1911 that produced 160 hp instead of the projected 1,000 hp .

The Thyssen Company built a number of these large generators between 1914 and 1927 , but only one went into service and it had a 43 inch turbine and drove generator for the Prussian State Railway .

The laws of thermodynamics will beat this updated version, the same as it did the earlier ones :-((

Cheers
John

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Re: pulse detonation valveless gasturbine

Post by ace_fedde » Sun Jul 26, 2009 3:42 pm

John,
Can you explain in simple words, I understand physics though, where the "leak" is?
Fedde
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Re: pulse detonation valveless gasturbine

Post by racketmotorman » Mon Jul 27, 2009 12:50 am

Hi Fedde

Its a very interesting design , not really a turbine engine , more a "normal??" IC engine that has a rotating piston/"crank" assembly .

The info states they are using hydrogen fuel , great for explosive combustion , but not the easiest/cheapest/greenest fuel around as its production/distribution has its cost/problems .

From the "hype" being spread by the literature it sounds like they're "fishing" for development dollars , no hard cold "verifiable" facts .

If as they claim they have 80 atmos of peak pressure and a mean of 20 , there'll be massive leakage on the "turbine" , also potential expansion/clearance problems between hot rotor and cold casing .

Interesting ....BUT .................we'd need more info before its a proven possibility

Cheers
John

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Re: pulse detonation valveless gasturbine

Post by Viv » Mon Jul 27, 2009 2:57 pm

Hi Fedde

It looks like its no more than an investment engine with all those claims of wonderful sparkling performance, I could be wrong but I have seen this one before and it all looks way to good to be true, btw an investment engine is were a bunch of like minded people set up a project based on some exciting technology, they scam the local development agencies for startup cash then start on attracting investors, with a smooth talking Monsieur Ponzie type as the promoter it works well until they run out of sparkling imaginary progress reports or the promoter gets found out as a bull shitter or thief.

Research and development tax credits are another cash scam investment engines use to bring money in, basically they carry out highly questionable research on their secret technology and publish bull shit reports of fantastic success, the goal is to put in an R & D claim to the revenue agency so they can claim back 50% of the fictitious costs of the development they carried out.

These types of company are always on the point of a breakthrough that will launch them in to the big time and make every one involved millionaires, but they always need just a little bit more investment money or just a little bit more time etc etc etc.

Viv
"Sometimes the lies you tell are less frightening than the loneliness you might feel if you stopped telling them" Brock Clarke

Viv's blog

Monsieur le commentaire

ace_fedde
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Re: pulse detonation valveless gasturbine

Post by ace_fedde » Mon Jul 27, 2009 5:13 pm

Well Viv, and John,

I think you can be totally right there when talking about scam and the hugh amount of "new engine types". But as you probably noticed its not all scam.
I used to, for many years, follow all the news about automotive engines. Many new promising concepts past but never made it to reality.
The simple reason is that our old friend, the i.c. piston engine, has been developed so far and has become so sofisticated.
Many new designs that might have a better efficiency on paper, simply cannot catch up with this development position of the i.c. piston engine, and lose the race.

Back to our PDE-turbine. Well that's the first thing I'm asking myself: Is this really an PDE in terms of Detonation, or stands the D in PDE for Deflagration?
There is some interesting thread, explaning detonation, in the PDE forum:
viewtopic.php?f=12&t=1418 and there is more there.
Many times the word detonation is used to easy, just to describe an explosion (so a deflagration). With detonations the shockwaves travel faster than the speed of sound, for deflagrations they are subsonic.
If the graphics that show the technology also represent the real geometry, I doubt there is any real detonation since it is pretty difficult to cause a detonation in a short and small CC.

If there are real detonations occuring, there might be something interesting about this idea.
I have a feeling in my guts (as John says :lol: ), meaning I'm not sure it's true what I say here, that a detonation produces relatively less thermal energy (read: heat loss) and more kinetic energy (shockwaves), compared to a deflagration with the same amount of (total) energy release.
So it looks like to me that a significant part of the energy that is normally used to create heat (with deflagrations), is now used to create the supersonic shockwaves. Off course both processes also produce "normal" expansion.
With a piston engine you can't do nothing usefull with those supersonic shockwaves, the pistons are travelling to slow and these waves might even destroy your pistons. The same results we will find with the conventional turbine.

The PDE-turbine looks to me (just) interesting as a first stage after a CC (that creates less heat!). The PDE-turbine converts then only the shockwaves' kinetic energy into work. A few of these setups are coupled, to create a more constant flow/ expansion (expansion is not done yet after the PDE-turbine), followed by a more conventional turbine that extracts work through expansion.
So let's start building...

Fedde
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Re: pulse detonation valveless gasturbine

Post by ace_fedde » Sat Oct 17, 2009 9:12 pm

ace_fedde wrote:I have a feeling in my guts (as John says :lol: ), meaning I'm not sure it's true what I say here, that a detonation produces relatively less thermal energy (read: heat loss) and more kinetic energy (shockwaves), compared to a deflagration with the same amount of (total) energy release.
So it looks like to me that a significant part of the energy that is normally used to create heat (with deflagrations), is now used to create the supersonic shockwaves. Off course both processes also produce "normal" expansion.
To understand what I'm saying there and to envision read below and imagine.

Take a long tube that is closed on one side and put a tiny amount of explosive in the bottom of that closed tube. Now detonate it. It will produce (under the right circumstances) a supersonic shockwave travelling through, and coming out of the tube, with a peak pressure (for an instance) of around 20 bars at the end of the tube (and travelling further).

Now take that same setup but don't detonate the explosive, burn it (yes, many explosives can also burn!). Now there will not be any pressure wave at the end of the tube, just combustion gasses flowing out. If we want pressure we have to close also the other end of the tube before we burn the explosive.
We will see then that (for longer tubes) we will not get the 20 bars, but probably we are getting lots of heat. And if we open the tube we see a much smaller pressure wave than the detonation shockwave. In this case the energy of the pressure wave is "created" from pressure that is created from thermal expansion and physical expansion(combustion products) which creates flow (kinetic energy)

So where we start with the same amount of chemical energy, in the case of detonation we end up with much more (kinetic and pressure) energy in the pressurewave than in the case of deflagration.
Where is this extra energy coming from? Energy can not be created, only converted, so there must be a reduced heat production in case of detonation. It seems like a part of the chemical energy is directly, without heat production, converted into kinetic energy.
That is actually very nice since heat is (mostly) the least desirable form of energy.
Many forms of energy can be (almost) completely converted into another one (like into desired work) while heat cannot be completely converted (the classic anergy-exergy problem).

Right?? (meaning I'm not claiming the above, but suspecting)

Fedde
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Re: pulse detonation valveless gasturbine

Post by MTC » Sat Apr 17, 2010 3:07 am

I do not see how this is a detonation engine at all. As I understand it (not that saying too much) detonantion is a spontanious chemical reaction and burning is rapid oxidation.

As for the engine its self. It can only generate power on about 1/4 of the wheel. Or the expansion extends past only 1/4 of the revloution of the turbine wheel. It seems that there would be a sizable lack of efficiency there. Sealing the wheel in to prevent blowby is also difficult.

With that being said I have been working on my own projects for years and it is tough. Not giving to much information but hopefully giving enough to get people interested.

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