Solving the Tesla Turbine Bearing Temperature Problem

[BernieM]

I see a lot of references to the 'efficiency' of the Tesla turbine, however, I can't find any actual data. Does anyone have a handle on actual achievable efficiencies of the tesla turbine?

 

[Isarmann]

I was just wondering about that very point earlier today... The question that occurred to me was, "Is the boundary-layer effect more efficient in transferring energy to the turbine impeller than the 'old-style' direct-impingement method?" I did see a small video illustrating the concept of the tesla turbine just today, running on compressed air, but really it didn't show anything (even implied) about how well it works...

An unrelated article I saw earlier today was discussing the efficiency of engines and pointed out how sloppily the term is used these days... some were talking about thermal efficiency, some electrical efficiency, some mechanical efficiency... and all seemed to be hinting at (or trying to imply) that the overall efficiency of the system (power in; power out) was what was under discussion.

Although Tesla's turbine has been around, as an idea, for a long time; it seems to me that it's only been recently revived as an experimental thing... So it seems to me quite likely that there is no experimental data of the type we'd like to see-- some of the first-order research that needs doing, I would think, is to build and test models to collect exactly that kind of experiential data.

Let me know if you hear anything on this...

 

[Jupiter6]

I see a lot of references to the 'efficiency' of the Tesla turbine, however, I can't find any actual data. Does anyone have a handle on actual achievable efficiencies of the tesla turbine?

I've read everything from 25 to 95% but have found 40-60% to be believeable, based on videos. I scavenged our engineering library on the subject but didn't find anything more than a paragraph related to the subject. Apparently, the efficiency goes down as the rotor spins faster which I imagine is due to the centrifugal force counteracting the corkscrew effect. While researching, keep in mind that these are also referred to as boundary layer turbines and fixed disc turbines. The best resource I have found so far is:http://www.teslaengine.org/

 

[Isarmann]

Yeah--- that's the kind of numbers I've seen, too; and they strike me as little different than those projections one sees based on the theoretical efficiency of Carnot cycle engines and whatnot--- not much more than a guess, really. I would consider 50% (in the middle of your reasonable range) as an acceptable compromise between optimism and foolishness, until we can get our hands on actual data...

One thought on the speed: after considering for a bit, I think your hypothesis misses the mark--- boundary layer effect is based on friction, and it won't change because of a tangental force... think of rotorcraft or airscrews--- they don't seem to 'throw off' air in the plane of the spinning disc, which they clearly would if this were a true phenomena. So what does explain the decreasing efficiency? Speed alone, I think! Consider; in most systems where you have a differential, like heat differential or what-have-you, as the differential closes, efficiency drops... Like heat engines, less efficient the closer the hot and cold sides' temperatures are.

I'm thinking that, as the speed of the turbine approaches the speed of the stream of working fluid, the boundary layer effect becomes less and less...

Consider: An object is moving at a given speed (100m/s) through air... there is friction, there is a boundary layer effect. Now increase or reduce speed by 1m/s--- what is the result, in terms of boundary layer effect? Negligible, it seems. Take a stationary object and subject it to a 100m/s airstream, and the effect is noticable. I think that might be a more accurate picture of why the efficiency, however high or low it is, changes as the turbine's speed increases.

 

[Jupiter6]

I kinda see what your getting at Isarmann however I don't feel air moving axially through a prop is a good comparison to a fluid corkscrewing radially inward. However, even in the tiny contact time between air and a prop blade, rotorwash does spiral outward due to a tangential component imparted by the prop blades. The boundary layer is a small part of a prop whereas it's everything in the tesla turbine.

I'm thinking that, as the speed of the turbine approaches the speed of the stream of working fluid, the boundary layer effect becomes less and less...

Exactly. The centrifugal force disrupts the corkscrew and creates a back pressure to the incoming fluid. I believe they call this "gating". There is literature on this avaiable on the web. I feel you and I approaching the same reasoning from opposite sides.

 

[RonL]

I think you will find the patent that Tesla filed will give you the best information of what can be expected for the turbine.

Not sure how well i remember, but two things he made reference to, was a thermodynamic conversion, and that best efficiency was achieved at about 50% turbine speed/ inlet velocity.

 

[Isarmann]

I definitely think we're on the same page, and think you might be right; we're talking about the same thing... But there is a lot of imprecision out there when it comes to explaining the mechanism of agreed-upon phenomena, so I always find it interesting to try to come to understanding of the actual effect at work. I will definitely have to learn more about the centrifugal force in this situation; thanks for the steer on the word "gating". But leaving that aside for a moment (let's say we come up with a method that will negate that effect entirely), wouldn't you think there will still be an efficiency drop as the linear speed of the turbine approaches the speed of the stream driving it? So, assume there is no disruption of the corkscrew at all--- won't we still have efficiency drop as an expected result of the speed differential approaching zero?

I actually found out about Tesla turbines because of work I've been doing on vortex phenomena of all types; it seems like vorticies are one of those (I think of them as 'magic') areas of science where you get a synergistic payoff from what goes in... Of course, there's no such thing as a free lunch, but some things (like latent heat, for example) really seem to have potential benefits that in some way 'go beyond' what you might expect.

I wouldn't be suprised if the 'corkscrew' or vortex effect in the Tesla turbine is an important (if not indeed critical) component of how it functions in the first place.

 

[Isarmann]

Yes, RonL, that's what I was thinking; there must be some optimum relationship between the incoming charge speed and the turbine's speed.

Leave it to you to go to the source and make light of all our serious musings... LOL... just kidding, of course.

I should have thought to read the patent...

Have you guys noticed how often a post, which must've taken ten minutes to write, would be obviated by as little as 3-5 minutes of reading on the subject? I find myself thinking "Wikipedia, silly!" all the time on here when reading some of the less-well-informed posts...

 

[RonL]

I definitely think we're on the same page, and think you might be right; we're talking about the same thing... But there is a lot of imprecision out there when it comes to explaining the mechanism of agreed-upon phenomena, so I always find it interesting to try to come to understanding of the actual effect at work. I will definitely have to learn more about the centrifugal force in this situation; thanks for the steer on the word "gating". But leaving that aside for a moment (let's say we come up with a method that will negate that effect entirely), wouldn't you think there will still be an efficiency drop as the linear speed of the turbine approaches the speed of the stream driving it? So, assume there is no disruption of the corkscrew at all--- won't we still have efficiency drop as an expected result of the speed differential approaching zero?

I actually found out about Tesla turbines because of work I've been doing on vortex phenomena of all types; it seems like vorticies are one of those (I think of them as 'magic') areas of science where you get a synergistic payoff from what goes in... Of course, there's no such thing as a free lunch, but some things (like latent heat, for example) really seem to have potential benefits that in some way 'go beyond' what you might expect.

I wouldn't be suprised if the 'corkscrew' or vortex effect in the Tesla turbine is an important (if not indeed critical) component of how it functions in the first place.

I think you are on spot with the vortex and turbine working together.
In the past I have used a vortex tube cooler, and much later found a detailed description of how it works, in a refrigeration Manuel, the air in is broken into three values
1. cold air out
2. hot air out
3. internal friction of the air against the tube wall

In my opinion this turbine is a segmented flywheel, that can transfer thermal energy from the atmosphere, a key issue, is to enhance the separation of the delta T, and pressure differences within the blades. This is the area that caused Tesla much grief (in my opinion) too much thermal difference in a small area led to blade distortion.

There might not be a free lunch here, but if not i think a good snack might be in store (as long as we have sunshine everyday)

 

[Isarmann]

Hehehe... I like that.

I really wonder about the thermodynamic component myself... I'd really love to see tests done (or do them myself) to establish some of these things we're wondering about.

 

[RonL]

Hehehe... I like that.

I really wonder about the thermodynamic component myself... I'd really love to see tests done (or do them myself) to establish some of these things we're wondering about.

In my mind an area of focus that most researchers miss, is how little can they get by with. The general approach is to build for high pressures, and output from the least size, which equates to higher cost in almost all respects.

I'll share a few of my thoughts and efforts to devise a plan for slower speed and more volume, no real details, but rather what and why.
First as i see it, the vortex tube puts out air at two (in general) temperatures, which is a compromise of volume at each end, the temperature varies from extreme cold at the center to very hot at the wall of the tube, air friction put an effort toward twisting the tube, and if the tube is allowed to rotate some of this energy could be recovered.

The refrigeration Manuel gave the values as follows,
air in 25 CFM,
100 PSI(794 kPa), and
temperature 100 F (38 C),
75% of the air spirals inward, expands and cools to 40 F (4 C), the other 25% of air churns in the tube, heats up to 270 F (132 C).

Air enters a spin chamber at a tangent and forms a cyclone effect, spinning at 500,000 RPM, air tries to speed up to 5,000,000 RPM while spiraling inward, is retarded by the air column in the tube, forcibly turns column with an effort equal to 1/2 horsepower.

The size of the tube is less than 1" Dia. and the spin chamber is 2" Dia. or less, an overall length of around 8".


This should give a good idea of thermal change in a vortex and this is with no moving parts.
Inserting a turbine and increasing the diameter will have a great effect on the speed of things, but a thermal change will still take place.

My plan is to use 4 canister vacuum units working in series, 1 unit on each side of the turbine pulling a vacuum at the center discharge ports, and plumed to push air toward the other two that are in series and blowing air at an increased velocity into the turbine at a tangent.
The heat from the motors will continually be cycled thru the air flow, and the insertion of jet ejector principles will allow for a replenishing of warmer air from the atmosphere.

Some cold air discharge will take place between the two vacuum units and the two pressure units.

My turbine will consist of common 10" saw blades rated for 7,000 RPM, and the center hole between 1" and 2" there is a total of 8 holes to use for bolting the pack of blades together and i will use a slightly larger spacing between the blades. The carbide tips will be left in place and hopefully act as impact blades, they are at angles that should prove useful against the air flow. The blades are about 1 pound each and i plan to use around 30 in the stack.

Another idea that i started a patent for in 1996 (but did not follow thru) is to allow the blades to move crosswise, this will produce a slide action and give the turbine a variable volume, creating the possible cycle for building and depleting pressure of the air flow.

As for taking power off the turbine, i'll leave that alone for now because the post is getting too long, hope some of this will help anyone that has an interest in Tesla's Turbine.

A good book for reference is " The Tesla Disc Turbine" by W.M.J. Cairns, I.Eng., M.I.E.D.

 

[Argentina]

I think that the end of this discucion is to build a series of different sizes of turbines and variables. Compress air and get how much energy it takes to do it, then expand it on the diferent turbines, at diferents presures and speed to see how much energy you recover. If nobody wants to modeling the system by computer to get the best values of the turbine, disc, gap dimensions and speed of the fluid in motion. The practice will be the only way out. I am trying to find someone who do the modeling because i have to make a thesis to end my career of mechanical engineering.

 

[Isarmann]

I agree, Argentina... I have reviewed all of Tesla's patents on the turbine, to better understand his own thinking on the advantages of the design; based on those I have some comments I will post a bit later. I think we can come up with a 'standard' design that features easily-changed major variables that should allow us to establish the numbers we seek.

 

[RonL]

I think that the end of this discussion is to build a series of different sizes of turbines and variables. Compress air and get how much energy it takes to do it, then expand it on the different turbines, at different pressures and speed to see how much energy you recover. If nobody wants to modeling the system by computer to get the best values of the turbine, disc, gap dimensions and speed of the fluid in motion. The practice will be the only way out. I'm trying to find someone who do the modeling because i have to make a thesis to end my career of mechanical engineering.

Hi Argentina, and Isarmann

It would be great if you find a thermal modeling program to evaluate the turbine action, and share with the forum, your findings.

It is my thinking that, the compression of air you mention above, has to be a part of the turbine's energy cycle or you have too much loss outside the system.
A closed loop system should look exactly like a heat pump, with the turbine acting as the expansion valve, and giving it the ability to expand and contract the space between the blades, while turning, is important to the pressure/vacuum buildups.

So many things can be done with the basic design, it is good to see experimenters looking at Tesla's idea.

RonL

 

[Argentina]

Im trying to get FLOWORKS ( a tool for solidworks ) and see if i can get some data if i build a small 2 o 3 disc tesla´s turbine. First i have to know how the program works and if is usefull for this kind of things.

I will tell you if a know something else.

See ya

 

[Isarmann]

Yeah, I agree that modelling software is the way to go... I'm using pro/ENGINEER from PTC, and it does include a module to do mechanical stress modelling--- but I think the key would be something more like what Argentina mentioned; thermodynamic modelling. I know of a very capable product along those lines, but I'll have to look it up--- can't remember the name. I don't think floworks is the one I've seen before... I seem to remember a different name. Regardless, once we have some models completed in any of the programs, we should be able to move them to whichever analysis software.

I do believe they will show us exactly what we're hoping to see.

 

[Argentina]

I think the first step is building the turbine with the best efficiency to transform the motion of the fluid to motion on the axle. With the less turbulence and loss of boundary layer between the disc. I don't know if the floworks works with diferent surfaces on the materials, i hope so because i think there is the key ( also on the disc speed ).

 

[Isarmann]

Yes! I could certainly see boundary-layer and surface effects being considered second-order in the minds of those who wrote the programs; but for our purposes, they're clearly first-order effects. I think Flotherm (or Flowtherm) may have been the program I was looking at before, and it's main focus is overall flow through a system, showing hotspots, eddies, and the like.

I'm sure, even if they consdiered it a secondary consideration, that these programs must take into account surface textures, especially when the walls are close--- so hopefully, at worst, changing some of the values to emphasize that portion of the modelling would still give us the general analysis we're looking for. Actual testing of a built model will firm it up... As long as the software can help us avoid major missteps, I believe it will work.

 

[Argentina]

I need the EFD.LAB, that's the program we are looking for... If someone has it, please contact me. I can't find it.

 

[ank_gl]

There are a lot of efficiency for a turbine, thermodynamic efficiency(which one can get from tables), then there is a hydraulic efficiency(in case of water turbine) or blade efficiency(indicating how well blade is taking energy from the working fluid), then is mechanical efficiency.

The case of flow irregularities(non uniform flow, turbulence, boundary layer separation, fluid friction) all cause a dip in blade efficiency,

I am not sure which efficiency are we talking about here.

And output power is parabolic with speed, and assuming constant input power, efficiency(blade efficiency) ll take a dip with rpm

 

[RonL]

The test engine I designed and am now building has more then enough variables for a proper parametric study. I can vary direction, disc diameter, disc spacing, and fluid entrance parameters. As I said it'll be enough data to keep me busy for at least 6 months.

Thanks NateD,

Best wishes in your trials, and data collecting, I'll look forward to your results. (I believe the turbine has great potential)

I wonder if we are on the same page about disc spacing? the design that i did not follow through with a patent application on, allows the turbine to vary disc spacing while in operation, this will give the ability to set a cycle pattern of both, high/low air volumes and temperature.

One other thought, if not in your plans already, might be to set up an operation where the turbine is turned by an electric motor, at a very controlled and steady speed, any airflow effects would show up in the motor readings.

RonL

 

[RonL]

When I started looking at the Tesla Turbine I too looked at varying the disc spacings. I have concluded since that there are better ways to control the throttle. What I have done is designed the engine around max operating power. Varying the spacing of the discs sets up many problems that there are better solutions to dealing with in my opinion. One big issue I've thought about with a variable geometry version is sealing the case properly so there aren't big leaks.

Additionally varying rotor spacing makes things unnecessarily complicated. As an engineer I stick to the KISS methodology.


As to the motor idea... its worth looking into, though I think there is a big difference in the way the air moves when forced into the engine vs when the engine is being used as a pump.

Though I suppose if one could characterize the engine operation as a pump one could superimpose the results onto a forced fluid version. And therefore get a hybrid math model. I'm still not sold on the idea.

The very same data should jump out once my tests are done. The hardest parameter to measure of course is pressure distribution across the discs. But really the most important is to fully characterize the parameters that change as operating and engine parameters change.

What backgrounds do the people on this forum have?

I have a BS in Aerospace Engineering with a specialty in propulsion systems.

Nate

Nate, I do not have a degree, what little I do know comes from association of power tools, and equipment that has been used in work and home applications, I depend on the spec plate numbers (on quality equipment) for power ratings for most things.

In recent years things have changed a little, it really gets my blood rate up, when retail tools claim things like, 6.5hp, then when you look at the data plate, the motor draws 10.2 amps@115 volts, (where's the truth in advertising??)

My two largest equipment units are, a 50,000 pound (1948) fully mechanical "Link Belt" drag line, and a fully hydraulic (1990) 53,000 pound "poclain" excavator, then a compliment of smaller things all the way down to hand tools.
I have a "Bobcat" skid loader, that is powered by a 27hp engine, it weighs about 3400 pounds, and is fully hydraulic driven. Knowing and understanding how it performs work, (power, weight, traction) and without any numbers calculation, one can say why a more powerful engine would be almost a complete waste.

Doing all my own repairs gives me cause to learn how to take things to the limit, and just short of breakage. (sometimes I miss, but not often)

My studies over the last few years have been random, and unstructured, producing a quite varied array of knowledge, but without a solid foundation in the basics.

My interest in Tesla Turbines began in 1972, but until 1992 very little information was easy to find. The early years of the net has produced too much over unity, and perpetual motion talk and has tainted images of the turbine.
I do feel that will change some in the near future, and I hope to put some efforts into my own ideas, which will make use of multiple types of energy transfers.

Sorry I got a little long winded (maybe I could use a little of that to power a turbine):zzz:

Ron

 

[Argentina]

Hello...

I went to a very good technical high school and now I am in the last year of mechanical engineering in the university.
Here in argentina the m.e. is more based on materials than thermodinamics, so i have a large gap between my knowledge and the one that i want to have.

Best wishes on your investigation and i hope for good results

 

[chayced]

I think there are a lot of misconceptions with regard to Tesla turbines. The first of which is a misconception that centrifugal force acts against efficiency. Quite the opposite in fact. . In a Tesla turbine this fluid enters at a high velocity at the outside of the disks, where rotational velocity is high, and exits in the center where rotational velocity is low. If it were not for the centrifugal forces on the stream as is spiraled down the fluid would quickly find the center of the turbine. In having a centrifugal force the fluid itself is forced to have a nearly constant difference in velocity from the disks for the entire spiral downward. This is nearly pointless with water or other liquids, but with steam or even air this allows for extracting energy continuously and uniformly through varying densities. I'm not saying that the turbine has some sort of magical efficiency properties, but the balancing of forces on the fluid does allow a single simple turbine to act on a wide range of fluid densities.

Another misconception: the Tesla turbine does not act from friction, but instead boundary layer interaction. Friction is used in some designs to aid in low speed torque, but it's not desirable for efficiency. If you are going to build a Tesla turbine for efficiency testing then both nozzle design and disk spacing are key. If I'm not mistaken the actual airflow should exist between the two boundary layers of the surrounding disks, and only in a small gap there. That way there is a balance between the fluid stream pressing on the boundary layer, and the boundary layer pressing back. Minimal friction with force still being imparted from a moving fluid to a nearly stationary one with a small difference in velocities between the two.

Hope that helps a little.

 

[RonL]

I think there are a lot of misconceptions with regard to Tesla turbines. The first of which is a misconception that centrifugal force acts against efficiency. Quite the opposite in fact. . In a Tesla turbine this fluid enters at a high velocity at the outside of the disks, where rotational velocity is high, and exits in the center where rotational velocity is low. If it were not for the centrifugal forces on the stream as is spiraled down the fluid would quickly find the center of the turbine. In having a centrifugal force the fluid itself is forced to have a nearly constant difference in velocity from the disks for the entire spiral downward. This is nearly pointless with water or other liquids, but with steam or even air this allows for extracting energy continuously and uniformly through varying densities. I'm not saying that the turbine has some sort of magical efficiency properties, but the balancing of forces on the fluid does allow a single simple turbine to act on a wide range of fluid densities.

Another misconception: the Tesla turbine does not act from friction, but instead boundary layer interaction. Friction is used in some designs to aid in low speed torque, but it's not desirable for efficiency. If you are going to build a Tesla turbine for efficiency testing then both nozzle design and disk spacing are key. If I'm not mistaken the actual airflow should exist between the two boundary layers of the surrounding disks, and only in a small gap there. That way there is a balance between the fluid stream pressing on the boundary layer, and the boundary layer pressing back. Minimal friction with force still being imparted from a moving fluid to a nearly stationary one with a small difference in velocities between the two.

Hope that helps a little.

I don't know how to say in words what I think, but in my mind is this not the same thing as induced drag on the surfaces of an airplane? The SR-71 Blackbird uses titanium because of the thermal build up due to the airflow.

The plane moves through the air, while the air is forced through the turbine.
I guess I don't really have a good understanding of how boundry layer and friction differ.

It seems to me that friction is the zone in which air is in solid contact with the surface and some distance out where slippage is almost resistance free.

Thanks in advance for any thoughts.

Ron

 

[RonL]

I don't know how to say in words what I think, but in my mind is this not the same thing as induced drag on the surfaces of an airplane? The SR-71 Blackbird uses titanium because of the thermal build up due to the airflow.

The plane moves through the air, while the air is forced through the turbine.
I guess I don't really have a good understanding of how boundary layer and friction differ.

It seems to me that friction is the zone in which air is in solid contact with the surface and some distance out where slippage is almost resistance free.

Thanks in advance for any thoughts.

Ron

Good example of my poor use of words

A clarification of the illustration used.

The SR-71 Blackbird uses power to force it's self through the air at speeds that produce tremendous heat because of friction.

If air of great pressure is forced into a spiral inside the turbine housing (producing in essence a vortex) the turbine blades are dragged along at some speed due to boundary layer adhesion, or as I have always thought (friction) corrections here please if needed:shy:

As I see it, the outer diameter is the absolute maximum of any torque application.
This highest pressure cannot be exceeded, as blade rotation keeps air from moving straight (spiral layers of diminishing energy air) to the center discharge.
Depending on energy removal from the turbine system, the velocity of air, and speed of the turbine, causes one or more layers of lesser energy(velocity) air to move to the low pressure center (I say try to pull a vacuum at this point) think of overlapping jet streams in our atmosphere.

Tesla used two terms, Viscosity and Adhesion, to me this implies friction and thermal transfer.
Based on vacuum storage, and pressure storage, my mind sees a delta T of value that exceeds durability of almost any material.
This equates to mass energy storage and cycle time.

Temperature controlled by, gas flow/energy removed.

Maybe the hardest thing for most people to comprehend, is the continued expansion of a gas into a continually declining volume. ( what helps me is to think of the volume of a cubic foot of air at the temperature of nitrogen, as opposed to 200 or 300 (C) or(F)degrees)
Once again thanks for any comments.


Ron

 

[RoaldFre]

Hi,

I've just made myself an experimental tesla turbine using 18 regular CDs, partly inspired by this forum thread.

Now I'm wondering on how to calculate the ideal converging-diverging nozzle to make it run most efficiently.
I guess the main things are the area of the convergent section (where it is smallest) and the increase in area in the divergent section(?)
I've searched the web but couldn't really find any actual equations on the subject that were usefull for designing a "de laval nozzle".
Any info is greatly appreciated :-)


RoaldFre

 

[russ_watters]

I haven't been paying attention to this thread, frankly, because I see no point to it. Tesla wasn't known for his fluid dynamics and a turbine he invented wouldn't necessarily have been any good even a hundred years ago, so why bother? In any case:

I don't know how to say in words what I think, but in my mind is this not the same thing as induced drag on the surfaces of an airplane? The SR-71 Blackbird uses titanium because of the thermal build up due to the airflow.

The plane moves through the air, while the air is forced through the turbine.
I guess I don't really have a good understanding of how boundry layer and friction differ.

It seems to me that friction is the zone in which air is in solid contact with the surface and some distance out where slippage is almost resistance free.

Thanks in advance for any thoughts.

Ron

There are two kinds of drag. The drag that occurs in the boundary layer (the entire boundary layer) is skin friction drag. Skin friction drag is drag that slows down the airflow in the vicinity of the object and the boundary layer is characterized by the velocity profile near the object (roughly parabolic velocity profile).

The other type of drag is pressure drag, which is due to the shape of the object creating a pressure disturbance in the air. Pressure drag is generally the bigger of the two.

In supersonic aircraft, skin friction drag is an insignificant factor. Virtually all of the drag and therefore virtually all of the heating is due to pressure drag from the shock wave.

 

[RonL]

I haven't been paying attention to this thread, frankly, because I see no point to it. Tesla wasn't known for his fluid dynamics and a turbine he invented wouldn't necessarily have been any good even a hundred years ago, so why bother? In any case:
There are two kinds of drag. The drag that occurs in the boundary layer (the entire boundary layer) is skin friction drag. Skin friction drag is drag that slows down the airflow in the vicinity of the object and the boundary layer is characterized by the velocity profile near the object (roughly parabolic velocity profile).

The other type of drag is pressure drag, which is due to the shape of the object creating a pressure disturbance in the air. Pressure drag is generally the bigger of the two.

In supersonic aircraft, skin friction drag is an insignificant factor. Virtually all of the drag and therefore virtually all of the heating is due to pressure drag from the shock wave.

The most extreme example I can think of, I'm sure that most have seen with their own eyes, or at least on film, is the return of the space shuttle. Surely the reverse action can be duplicated in a wind tunnel, and in my mind this is much the same as blasting high pressure air through a Tesla style Turbine.

I think it might be significant that with supersonic aircraft, the shock wave is dispersed out into the low pressure resistance of the atmosphere, but in the turbine the pressure is forced between the blades, and has only one avenue of escape, which is to the low pressure center exhaust.

I would think the pressure drag being confined between the blades, increases the skin friction, and that both forms of resistance, while in the outside world are negative values to most mechanical things, are in fact positive to the turbine. A lot like the older friction drive systems in transmissions and construction equipment.

For the most part I think people try to get too much out of too little, and find the efficiency is not great enough to justify the efforts. Maybe lower pressure and more volume would work for some systems. Kinda like when blowing leaves with my Tim Allen leaf blower, 30 minutes of high pressure work, is totally destroyed by a quick gust of low pressure, large volume wind.

The point of the turbine is that it is so simple in construction, and forgiving in precision of build, and materials can be very common, and cost far less than most other turbines. One must be aware of limits, and design accordingly.

Ron

 

[cr0ck3t]

... I will definitely have to learn more about the centrifugal force in this situation...

A funny cartoon about 'centrifugal force'

http://xkcd.com/123/

Hope you enjoy!

 

[Rohan2008]

I found the following article written by Earl Colby Pottinger sometime back... I think the link is down due to some reason and so I feel that the article should be not get lost.
Link: http://www3.sympatico.ca/earlcolby.pottinger/1632/1632_Stories/The_Trouble_with_Tesla.html

The Trouble with Tesla:

Like a number of people I have gotten together a number of flat disks to try and make a working Tesla turbine (yes it was easy to build and it did work.) and then I tried hitting the web-sites for some information to improve it.

First problem I ran into, many of these sites seem to be ran by "true believers", they lack not only turbines doing real jobs, but even real numbers for the machines they have built. Some of the claims are for more energy out than energy in, something I know is impossible! When you see that claim, you know you are dealing with a kook or a con-artist.

Second problem, a lot of them seem to think that they are going to make fortune when everyone starts to using Tesla turbines instead of IC engines. Because of this they have on purpose left out some of the construction details on their web-sites. Anyone who tries to build a Tesla turbine without figuring out the fine details will have piece of junk as far as performance is concerned.

Third problem, I have *NEVER, EVER* seen what appears to be a reliable report on the performance you can expect from a Tesla turbine. Can it be 25% efficiencies? I believe so. Can it be a lot more? I don't know. Additionally, I do see a lot of problems trying to get it to be better. It just is not worth the money and effort to me personally to try and do all the things needed to find or create the better designs.

________________________________________

Common problems promoters of Tesla turbine designs do not mentioned:

Disk Mass: Because it is easy to stack a large number of disks in a small volume some of the web-sites about Tesla turbines like to report in Horsepower per cubic inches to show how much better than IC (internal combustion) engines Tesla designs are. Of-course in real life how small your engine is matters less than how heavy it is, and it is easy to make a heavy Tesla turbine. In terms of horsepower per kilograms weight Tesla turbines do not do that well unless the disks are very, very thin. Thin but strong disks however turn out not to be so easy to make or cheap in costs as you would think at first.

Disk Speed: Tesla turbines can spin very fast when they are not under any loads. Very fast indeed! Because of this it is easy to surpass the strength of most common metals and plastics used to make the disks just by using input feed pressures in the 100s of PSI if you are using compressed air or a steam boiler. Once a high speed turbine starts to fail due to centrifugal effects any unbalanced forces will quick tear the disks apart to the point that the breakup of the disks acts more like an explosion than anything else. This high speeds problem add two more concerns - balanced disks & gearing down the speed.

Balanced Disks: The high rate of rotation means any imbalance in any of the disks will generate large side forces that even if they do not interfere with the operation of the turbine, they will drastically increase the wear and tear on the bearings holding the main shaft of the turbine.

Gearing Down: Tesla turbines are well know for their very high speed/low torque output. One needs a very high gear ratio to reduce the rotation rate down to something usable with most machinery, but one does also gain a high torque on the geared down output. However, the low torque of the Tesla turbine's main shaft means it is very sensitive to the friction of the main pickup gearing and bearing, plus that gearing will need to operate at a high rate of speed as well.

Disk Spacing: The performance of the Tesla turbine depends on the boundary layer, a simple rule (not a fixed one) is the best performance is with a gap between the disks of 3-5 times the thickness of the boundary layer. However, this layer's thickness depends on what fluid you are using (i.e. air, water, steam, condensing steam, combustion gases, ...), it's speed when injected, it's temperature at all points inside the turbine, and the same for the pressure and still a number of additional factors. I noticed very, very few sites try to figure how thick this layer is, then space out the disks according to that data.

Flat Disks: Now here is the true real killer of Tesla turbine efficiency. Imagine a simple Tesla turbine, a stack of 11 flat disks each 10 inches in diameter with a .1 gap between them and an exhaust hole in the center 1 inch in diameter. The surface area for the driving fluid entering the Tesla turbine is the (Circumference (or Diameter times Pi) * the width of the input area) = (10*Pi)*(10*.1) = 10*Pi square inches or about 31.4 square inches. But the exit hole is only one tenth the size. So any fluid entering a Tesla turbine gets slowed down while inputting energy into the Tesla turbine and at the same time must exit from the smaller area of the exhaust hole. But notice it gets worse, the area of disk gaps doing the exhausting is (1*Pi)*(10*.1) = Pi or about 3.14 square inches but the area of the hole is .5*.5*Pi or about .79 square inches.

Exhaust Hole Size: To solve the two above problems we have to do two things, both affect the efficiency of the turbine. First we have to make the Exhaust hole closer in size to the surface area of outer surface. So we get sqrt(10Pi/Pi) = sqrt(10) = about 3.16 in radius if we exhaust from one side only. This of-course does not take care of the surface area of the exhausting disk gaps which are still too small at 6.32*Pi*10*.1 about 19.87 square inches. To make up for this we need to taper the thickness of the disks so as to increase the gap size between the disk's surfaces as they near the center.

________________________________________

Problems resulting from trying to fix the above:

Non-Flat Disks: Making the tapered disks is no longer the simple design most people claim the Tesla turbine as being. It requires a precision lathe instead of just cutting out sheet metal.

Balance and vibration: The metal disks need to be make of a very uniform material so that they can be balanced easily

Boundary/Gap spacing: With tapering disks you start to lose the ideal gap for efficient operation, if you change the taper to increase the flow the efficiency drops and the total power output drops. If you don't taper the disks to get efficient power conversion you get restricted flow and the total power output drops. Balancing how much taper is enough is again something I see missing off all the web-sites out there. Add in the fact that if you are using steam, combustion or other hot gases the nature of the fluid flow changes in different parts of the Tesla turbine as energy is extracted and gases cool because of this. Your disk design just became a major job.

Exhaust Size: K.E. = .5*Mass*V^2 as the fluid in a Tesla turbine tends to flow at the same rate the disks spins. If the exhaust hole is .1 the size of the outer diameter, a very rough guess is that the fluid exits with only .1^2 = .01 or 1 percent of the original K.E. This suggests that we can convert 99% of available power to useful output. That is why you see people raving about how great Tesla turbines are going to be. However, at that size of an exhaust the outflow is very restricted by the small exhaust hole and we get very little power. The redesigned exhaust is .632 the diameter of the input giving us the exhausting fluid as still containing 40 percent of the original K.E. So we have already seen the turbine drop from 99% to about 60% efficient. The restricted area exhausting from the disks into the exhaust hole 'suggests' 19.87/31.4 or another one third drop in efficiency. So already we see a big drop in possible performance and the disk gap issues will only make things worse.

Disk Surface finish: Again something rarely looked at. It should be clear that if the disk surface was perfectly smooth there would be very little drag to transfer K.E. to the disks. However, too much drag just turns the K.E. to heat in the disks and fluid. So what is the best finish to have on the disks? I have a guess, but that is all it is.

________________________________________

Conclusions: Building a simple but low efficiency Tesla Turbine is easy, however the moment you decide to make a real power plant from one the work needed is on the same order, maybe more to develop and build a I.C. engine. Tesla turbines do have a lot going for them, but high end designs are not that easy to make otherwise lots of people would be using them today already.

Earl Colby Pottinger

 

[Rohan2008]

NateD,

My background is not mechanical engineering. I can’t understand jargoned language and so please bear with me.

Most of the discussion in this thread seems to be around using compressed air with a Tesla turbine. I was wondering how net efficiency would vary if we use wet steam (say at 300C & 50psi) through the inlet and condense the steam at the turbine’s outlet, which is more like a rankine cycle. Steam condensation creates vacuum, which (I presume) would create a pull force compared to the push force of the compressed air.

Any data on this front would be helpful. Thanks.

 

[RonL]

Rohan2008,

I'm not sure what you mean by jargoned language.

What you are asking contains several parts. The first part is using wet steam which basically tells me the steam is of poor quality. The second thing is that the condensation of the steam is a result of the energy loss due to expansion or expansion through the turbine.

It is the pressure that drives the turbine not vacuum.

I can test on seam, however it won't be wet steam as that will chew up the internals more quickly then I'd like.

NateD,
One of my designs makes use of steam in a split use of the pressure and vacuum that you and Rohan2008 are talking about.
Steam Jet Ejectors are known for the large amounts of vacuum pulled by a small amount of steam. A closed loop system can have a steam generated in one location and being divided into two quantities where the larger quantity drives the turbine blades, and the smaller quantity feeds jet ejectors on each side of the turbine housing.

This allows the high pressure drive steam to move through the blades into a low pressure area, making a more efficient energy transfer, and also will be a point of condensing the steam back to liquid, where it is moved back to the steam generator.

Hope to see your results soon, as I feel the turbine has great potential.

RonL

 

[ank_gl]

A closed loop system can have a steam generated in one location and being divided into two quantities where the larger quantity drives the turbine blades, and the smaller quantity feeds jet ejectors on each side of the turbine housing.

it does happen, steam ejectors are used to pull vacuum while starting & are used as air ejectors from the condenser in steady state operation. However they are not meant to maintain low pressure as you suggested, that really depends upon the condensing temperature, lower the temperature in condenser, lesser is the saturation pressure of water

 

[RonL]

it does happen, steam ejectors are used to pull vacuum while starting & are used as air ejectors from the condenser in steady state operation. However they are not meant to maintain low pressure as you suggested, that really depends upon the condensing temperature, lower the temperature in condenser, lesser is the saturation pressure of water

I'm not sure how much difference is in the statement we both made. I have pictures of ejectors that have heating coils wrapped around the outside in order to melt the ice buildup that results from condensation due to the cold conditions inside.

The link below is a site dedicated to the turbine. He has the patent posted, and for anyone that has not looked at the patent as filed in the patent office, it is a slight look into the mind of a man that gave a lot in the field of electrical energy. He makes a comparrison of the turbine to the electric motor, and also makes his number 8 claim, a thermo-dynamic conversion device.

The closed loop design that I mentioned should work as a steady flow system, but will be most efficient as a higher pressure, fast cycle pulse function.


http://www.phoenixnavigation.com/ptbc/tesla1.htm

 

[Rohan2008]

Rohan2008,
I can test on seam, however it won't be wet steam as that will chew up the internals more quickly then I'd like.

Are you saying that wet steam would chew up tesla turbine... or any other components?
I was under the assumption that Tesla turbine, unlike the other turbines, can withstand wet steam... doesn't it?

 

[RonL]

Are you saying that wet steam would chew up tesla turbine... or any other components?
I was under the assumption that Tesla turbine, unlike the other turbines, can withstand wet steam... doesn't it?

This has gone a while with no reply, my thoughts are, unless the pressures are in the very high range, there would be little, or no pitting or damage.

 

[abpud]

NateD
How is your testing going?
abpud

 

[gary350]

I have been on the Tesla Forum for about 8 or 9 years. From time to time the subject of the Tesla Turbine comes up. As I recall the efficiency is low. If you check the Tesla Archives you can probably find the information your looking for. About 90% of the stuff writting about Tesla is total nonsense. I have no idea how all that crap came to be written and published as the truth. The guys on the TC forum can tell you what is true and what is not, I don't keep up with that stuff. I recall someone on the TC forum used about 40 old CDs as disks to build a Tesla Turbine to experement with. I did not read all the post on that but I read enough to know I don't want to build one. I have built several small hot air sterling engines, vacuum engines, steam engines, radial engines, and electric engines. Check out the videos I have posted on You Tube.

If you want to join the TC forum send an email to tesla@pupman.com and type only 1 word, subscribe in the subject line and the body then click send. You will be a member in about 24 hours and you can ask questions about the TT.

http://www.youtube.com/watch?v=J56D56rQV-Q&feature=related

http://www.youtube.com/watch?v=57GFrxz_mnw&feature=related



http://www.youtube.com/watch?v=iSBXcn4u4es&feature=related

Here are some pictures of my Tesla Coils. I have several TCs from 1.5" diameter to 10" diameter. The 4" TC will produce 24" sparks on 450 watts. The 6" TC will produce 52" sparks on about 1350 watts. My 10" TC will produce 12 foot long sparks on 12KW, it will produce a 24 foot circle of sparks in the back yard. It sets off every security alarm in the neighborhood for a 3 block radius and makes all the motion detector lights flicker like crazy. I only run it after dark in nice weather for short 1 to 3 minute runs, on and off for about and hour or so. I have not fired up my large TC is about 3 years. The neighbor lady always calls the police and the police love to watch the spark show in my yard.

http://home.earthlink.net/~gary350/tc4.jpg

http://home.earthlink.net/~gary350/tc3.jpg

http://home.earthlink.net/~gary350/tc2.jpg

http://home.earthlink.net/~gary350/tesla1.jpg

http://home.earthlink.net/~gary350/tesla2.jpg

http://home.earthlink.net/~gary350/tc10-4.jpg

 

[JoeEngineer]

Hi Everyone-

My background is thermalfluids engineering. I worked quite extensively on bladeless heart pumps during grad school, but my real interest was always in the turbines. I became discouraged over the years at all the junk out there, as many of you have discussed, regarding Tesla turbines. This forum has piqued my interest again though.

I do believe, from a thermalfluids engineering perspective, that the TT is indeed quite viable- and there is certainly much we can learn about it and probably from it. I would disagree with some of the comments that state the technology would have been developed by now if it were viable. The lack of TT development is likely more an issue of timing and history than mechanical viability.

That said, can someone help me filter through all the junk out there and direct me to some actual quantitative engineering data? There doesn't seem to be much real engineering done on this topic since Rice years ago.

I am curious about this test turbine Nate D has been talking about. Is this item complete? Where can I read about the results?

I think its high time people start sharing data- I do agree that this Turbine isn't going to make any single person or company rich-its simply too complex for a single breakthrough invention to take it to the get rich quick level. The technology will only progress incrementally if everyone shares their knowledge.

 

[RonL]

Hi Everyone-

My background is thermalfluids engineering. I worked quite extensively on bladeless heart pumps during grad school, but my real interest was always in the turbines. I became discouraged over the years at all the junk out there, as many of you have discussed, regarding Tesla turbines. This forum has piqued my interest again though.

I do believe, from a thermalfluids engineering perspective, that the TT is indeed quite viable- and there is certainly much we can learn about it and probably from it. I would disagree with some of the comments that state the technology would have been developed by now if it were viable. The lack of TT development is likely more an issue of timing and history than mechanical viability.

That said, can someone help me filter through all the junk out there and direct me to some actual quantitative engineering data? There doesn't seem to be much real engineering done on this topic since Rice years ago.

I am curious about this test turbine Nate D has been talking about. Is this item complete? Where can I read about the results?

I think its high time people start sharing data- I do agree that this Turbine isn't going to make any single person or company rich-its simply too complex for a single breakthrough invention to take it to the get rich quick level. The technology will only progress incrementally if everyone shares their knowledge.

His patent is #1061206 in the US Patent office. If you go to the USPO and look it up by number, Tesla talks in detail of how it works and why, It takes concentration to stay with the dialog, but I think you can come away with what you need.

I have shared an idea or two but have not had any indication that anyone has found them to be of interest.
1. Vacuum at the discharge ports
2. Blades that can actually be closed and opened while the turbine is spinning, this action can be spring, hydraulic, electric, or air, etc. What would be accomplished is an increase, then decrease of cycle pressure.

Ron

 

[JoeEngineer]

This has gone a while with no reply, my thoughts are, unless the pressures are in the very high range, there would be little, or no pitting or damage.

I am surprised no-one has jumped on this one...
The ability for the Tesla Turbine to run on saturated steam is one of the fundamental thermodynamic efficiency selling points of the engine.

Pitting from steam in the saturated vapor range can destroy bladed turbines true- but for pitting to occur you need some sort of impingement, and the severity depends on the angle of impingement. With a TT, unlike a bladed turbine which essentially relies on it, you really don't have any impingement issues other than potentially with the housing.

This gives the Tesla turbine a leg up because there is a tremendous amount of energy available in steam between the saturated point and dry point. Power plants attempt to use this energy with elaborate regeneration systems- but this is nowhere as elegant, not to mention compact, as being able run a turbine through the sat vap range.

Theoretically you would want to run your turbine with dry inlet steam close to the saturation point. The housing is stationary, so there would be the potential for pitting of the housing if the steam were not dry at the inlet. Once the steam enters the runners I wouldn't imagine there would be a large enough velocity gradient or impingement angle between the streamlines and surfaces to cause any pitting.

If the turbine were designed correctly you might even be able to put dry steam in and practically get water out. You probably wouldn't literally want to take it all the way to water though as this would effect your boundary layer formation.

The other thing I haven't seen discussed here is the Coanda effect- has anyone taken this into account?

 

[gary350]

I posted this question on the Tesla Forum. This is what I got.

There is a huge club of Tesla turbine builders in Milwaukee, Wisconsin. You
may wish to contact them for more information.

Technical papers I have read, published by Phd's and college researchers,
seem to indicate efficiencies about 18%.

 

[JoeEngineer]

I should have elaborated a little more-
I am quite familiar with Dr Rice's work on turbines and did a very extensive literature search back in 2004 when I was doing my bladeless pump modeling. I have yet to find accurate accurate CFD modeling or any published improvements. I am curious if anything new has been discovered on the topic in the past 5 years.

Seems to me most work among college researchers simply involves replicating and testing the efficiency of turbines documented in Tesla patents. I don't see much on the development end.

 

[RonL]

I should have elaborated a little more-
I am quite familiar with Dr Rice's work on turbines and did a very extensive literature search back in 2004 when I was doing my bladeless pump modeling. I have yet to find accurate accurate CFD modeling or any published improvements. I am curious if anything new has been discovered on the topic in the past 5 years.

Seems to me most work among college researchers simply involves replicating and testing the efficiency of turbines documented in Tesla patents. I don't see much on the development end.

I'm not an engineer and I didn't go to college, so nothing special here except the thought process.
To me, it seems most people focus on how much power from how small a machine, and this always reflects high speed and high price.
Has anyone ever suggested a turbine so big and slow, but with enough blades it can actually use the atmospheric pressure of 14.7 PSI as the prime source of energy?

Ron

 

[RonL]

I'm not an engineer and I didn't go to college, so nothing special here except the thought process.
To me, it seems most people focus on how much power from how small a machine, and this always reflects high speed and high price.
Has anyone ever suggested a turbine so big and slow, but with enough blades it can actually use the atmospheric pressure of 14.7 PSI as the prime source of energy?

Ron

Maybe a little help, stimulating some minds, can anyone see in their minds eye, the eye wall of a hurricane, or tornado ? now imagine that on a smaller scale with a T Turbine in the center, what effects will take place and where will air flow, and why ?

It happens in nature, with very distructive force, why is it so hard to see it in a very small and controlled system?

Ron

 

[Redbelly98]

Has anyone ever suggested a turbine so big and slow, but with enough blades it can actually use the atmospheric pressure of 14.7 PSI as the prime source of energy?

But one would need a pressure difference between the entrance and exit. If the pressure is the same everywhere, then there is no force to move the air.

In a hurricane, the pressure is lower than atmospheric in the center.

 

[RonL]

But one would need a pressure difference between the entrance and exit. If the pressure is the same everywhere, then there is no force to move the air.

In a hurricane, the pressure is lower than atmospheric in the center.

In a number of my post, that has been the thing I have mentioned, the pulling of a vacuum at the center and on both sides of the housing, my thoughts are that the power to pull the vacuum will be less than the energy coming in.

The precharge energy(starting the rotation) that builds momentum, keeps the spin going, which establishes a boundry between the atmosphere and the low pressure in the center of the turbine. This boundry is the results of the friction and adhesion between the blades as described by Tesla The low pressure in the turbine is developed by a vacuum impeller geared to the turbine axle, or an electric drive which might be much more efficient than a mechanical connection.

This vacumm addition as far as I know is an original thought that I have put forth. In 1996 I started a patent process and did not have everything needed to follow through.

In my mind I see a closed system that incorporates flash steam generated by electric coils, the steam being split into two energy levels, one to pull vacuum and another of greater value driving the turbine. The details are more than I have time for now.

Ron

Thanks for taking note of the previous post.

 

[JoeEngineer]

In a number of my post, that has been the thing I have mentioned, the pulling of a vacuum at the center and on both sides of the housing, my thoughts are that the power to pull the vacuum will be less than the energy coming in.

The precharge energy(starting the rotation) that builds momentum, keeps the spin going, which establishes a boundry between the atmosphere and the low pressure in the center of the turbine. This boundry is the results of the friction and adhesion between the blades as described by Tesla The low pressure in the turbine is developed by a vacuum impeller geared to the turbine axle, or an electric drive which might be much more efficient than a mechanical connection.

This vacumm addition as far as I know is an original thought that I have put forth. In 1996 I started a patent process and did not have everything needed to follow through.

In my mind I see a closed system that incorporates flash steam generated by electric coils, the steam being split into two energy levels, one to pull vacuum and another of greater value driving the turbine. The details are more than I have time for now.

Ron

Thanks for taking note of the previous post.

Hurricanes and Tornado's are not creating energy they are simply the result the transfer of heat energy- imparted by the sun- on the surface of the Earth driven by a difference in temperature between the ground and the atmosphere. The greater the temperature gradient between these two bodies the stronger the Tornado, Hurricane, etc. Important thing here is that the Tornado is not building up momentum and creating energy by some strange vortex phenomenon- in fact- as I mentioned above, there is a pretty straight forward energy transfer going on. Hot air rises, thus creates wind. The vortex formed concentrates this energy- but doesn't create any.

If you were able to create a true vacuum- like the vacuum in space- then yes you could run a turbine on 14.7 psi. You could imagine a system like this would require a very long exhaust pipe to vent into space. Of course the problem is the weight of all that air filling the pipe would negate the vacuum. For this reason you would have to generate your own vacuum- which is simple enough- trouble is, unlike space, any man made vacuum is finite. You would constantly have to pump down the vacuum as it was filled with atmospheric air to maintain it. The energy required to do so would cancel out any energy generated.

There are about a million ideas out there to create "free energy"- unfortunately they all violate the laws of thermodynamics.

The best thing for creative minds is to focus on developing more efficient means of generating power, knowing well the laws of thermodynamics. Perhaps some type of vortex could in fact make the turbine more efficient. I certainly agree with the out of the box thought process.

You might be onto something with the flash steam concept. I don't know that electric is the way to do it- but perhaps some combustible. As I stated before- I believe Tesla tailored this engine specifically with steam in mind, granted it works with combustion gas air and water, its really ideal for steam due to the ability to run sat Vapor. I am considering building a TT powered vehicle that runs on steam. The idea would be to flash boil water to make steam in a high efficiency HX. Obviously you would want to have steam pressure on hand almost instantaneously to make a viable vehicle. Steam lends itself well because any excess could be stored in an insulated pressure vessel. This way you could have a relatively low power boiler provide spikes of power to the turbine to enable quick acceleration with low overall energy use.

 

[RonL]

Hurricanes and Tornado's are not creating energy they are simply the result the transfer of heat energy- imparted by the sun- on the surface of the Earth driven by a difference in temperature between the ground and the atmosphere. The greater the temperature gradient between these two bodies the stronger the Tornado, Hurricane, etc. Important thing here is that the Tornado is not building up momentum and creating energy by some strange vortex phenomenon- in fact- as I mentioned above, there is a pretty straight forward energy transfer going on. Hot air rises, thus creates wind. The vortex formed concentrates this energy- but doesn't create any.

If you were able to create a true vacuum- like the vacuum in space- then yes you could run a turbine on 14.7 psi. You could imagine a system like this would require a very long exhaust pipe to vent into space. Of course the problem is the weight of all that air filling the pipe would negate the vacuum. For this reason you would have to generate your own vacuum- which is simple enough- trouble is, unlike space, any man made vacuum is finite. You would constantly have to pump down the vacuum as it was filled with atmospheric air to maintain it. The energy required to do so would cancel out any energy generated.

There are about a million ideas out there to create "free energy"- unfortunately they all violate the laws of thermodynamics.

The best thing for creative minds is to focus on developing more efficient means of generating power, knowing well the laws of thermodynamics. Perhaps some type of vortex could in fact make the turbine more efficient. I certainly agree with the out of the box thought process.

You might be onto something with the flash steam concept. I don't know that electric is the way to do it- but perhaps some combustible. As I stated before- I believe Tesla tailored this engine specifically with steam in mind, granted it works with combustion gas air and water, its really ideal for steam due to the ability to run sat Vapor. I am considering building a TT powered vehicle that runs on steam. The idea would be to flash boil water to make steam in a high efficiency HX. Obviously you would want to have steam pressure on hand almost instantaneously to make a viable vehicle. Steam lends itself well because any excess could be stored in an insulated pressure vessel. This way you could have a relatively low power boiler provide spikes of power to the turbine to enable quick acceleration with low overall energy use.

I just lost a too long answer.

I now, just have time to ask a question. Can someone give a summary of what Tesla meant when he claimed coverage in his patent, as a thermo-dynamic converter?

This has to be the area of my misunderstanding, what I think is (by some stretch) a mechanical solar cell, that does not need a direct interaction with sunlight.

Please do not mistake me for an overunity person.

Ron