RE: [TeslaTurbine] Tesla Turbine used as a Compressor?
- A tesla pump/turbine is very much a reversible thermodynamic engine. No clear idea what it's intrinsic loss mechanisms are in the limits that matter for a small system, but they should be good for a small turbine/compressor (the other small units are very inefficient so the competition is not hard to beat). The problem you must deal with is that it is not really a compressor. It is an accelerator. It takes slow air (or whatever) and makes fast air out of it. The fast air has to be slowed by a nozzle to obtain high pressure. This requires that the air "stick" to the sides of the expansion nozzle, and it is really complicated and dynamic if the air is supersonic (the nozzle has to shrink and then expand, a De Lavel nozzle, like a rocket engine), which it has to be to get very high pressures. The "stick to" requirement seems to me to introduce an instability. As the back pressure increases, the gas has a greater tendency to come unstuck, until at some point it does. At that point the expansion induced by the nozzle is reduced, the outlet pressure is reduced, and the back pressure causes more of the nozzle to unstuck. That may produce pressure surges if the output is not drained off fast enough to hold the back pressure down. Sort of the reverse of the normal compressor where you reduce the flow and the pressure goes up. In this case if you reduce the flow below a critical value, the compressor would begin surging. I think. Based on analysis and not experience.BTB, in the "other" regime, the TT will act as a centripetal compressor. I think it is much less efficient in that mode, and the final pressure is much lower. The only folk I have seen try to use a TT as air compressor have not had a very good idea of how it performs as gas accelerator with nozzle, and have had generally poor results. A standard leaf blower, vacuum cleaner, centripetal compressor works quite well and has a lot higher coupling between the drive and the gas, (meaning that a much smaller unit can produce a much greater flow of gas).
From: telknordragon [mailto:telknordragon@...]
Sent: Thursday, February 01, 2007 4:26 PM
Subject: [TeslaTurbine] Tesla Turbine used as a Compressor?
I have seen a few small Tesla turbines in action. They ranged from 4
inch to 36 inch diameter on the disk stacks. The PSI on air needed to
run them ranged from 40 - 4000. I would like to build one that has a
HP output of 300 but still be small and not need massive amounts of on
site air storage. My main question is can a Tesla Turbine be used
backwards to compress air? I have seen one used to pump water so can
it pump air like a compressor into an air tank for later use?
- If you put both on a single shaft, use the low pressure to turn the smaller diameter turbine. Then the compressor should output a stream of gas at a higher velocity and the nozzle will compress this to a higher pressure. Note what I said before about the supersonic issue. If the pressure is high enough, you will need a Delavel type nozzle.
From: Shadow of the Redwood [mailto:priyaawara@...]
Sent: Thursday, February 01, 2007 7:15 PM
Subject: Re: [TeslaTurbine] Re: Tesla Turbine used as a Compressor?
Actually, If you look at tesla's patent, it is very similar to what you describe with the pulse jet engine. He used the "valvular conduit" as a backflow prevention device and fed combustibles into the chamber.
just so I understand you right... you want to use compressed air (50-100 PSI) to run an air compressor that would compress air to a higher PSI?
Yes, similar to a Jet engine, multi-stage compressor.
Just thinking it over in my head, it seems like you would use the larger disk pack on the lower PSI side.
However, if the packs are on the same shaft, both packs would travel at the same speed and you would not gain any pressure.
It seems to me, that you would need to have some gear reduction system that would drive the smaller pack at a higher rpm.
telknordragon <telknordragon@ yahoo.com> wrote:--- In TeslaTurbine@ yahoogroups. com, Shadow of the Redwood
<priyaawara@ ...> wrote:
> I don't see any reason why not.
> Make sure to optimize your disk spacing for the medium you are
working with... I have seen some figures around here that range from
7-20 thousanths, depending on if you are using air, steam or water.
> ... If you are running it "backwards" what are you running it on?
Well Pri I was thinking of a 6inch turbine coupled to a 10inch one.
The 6inch one being powered by compressed air and the 10inch one
compressing the air into tanks. Or would the turbine disk be the
other way around with the 6 inch compressing and the 10inch being
powered? Basic idea of what I'm trying to do is like a Jet engine
with air storage tanks holding air in place of a jet's combustion
chamber. Though I don't see why one couldn't put a combustion chamber
and make Tesla Turbine Jet drive. I've seen one Tesla Turbine powered
by a pulse-jet engine. The guy did not disclose the materials that
the turbine was made of and did say that the turbine disk stack was
destroyed in a later run when he hit higher RPMs than the materials