- #36
NateD
- 647
- 0
I am nearing completion of my turbine unit. Does anyone have any specific data collection requests? I may be able to provide some limited data.
Solving the Tesla Turbine Bearing Temperature Problem
- Thread starter BernieM
- Start date
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- Efficiency Tesla Turbine
In summary, the conversation revolves around the efficiency of the Tesla turbine, with participants referencing various sources and discussing possible factors that may affect its efficiency. There is a lack of concrete data available and the efficiency seems to vary based on theoretical projections. Some participants believe that the efficiency may decrease as the speed of the turbine increases, but there is also mention of the centrifugal force potentially disrupting the corkscrew effect and creating a back pressure. The patent filed by Tesla is suggested as a potential source for more information on the turbine's efficiency.
- #37
Rohan2008
- 4
- 0
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
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
Last edited by a moderator:
- #38
Rohan2008
- 4
- 0
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.
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.
- #39
NateD
- 647
- 0
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.
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.
- #40
RonL
Gold Member
- 1,107
- 219
NateD said:
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
- #41
ank_gl
- 741
- 0
RonL said:
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
- #42
RonL
Gold Member
- 1,107
- 219
ank_gl said:
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
- #43
Rohan2008
- 4
- 0
NateD said:
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?
- #44
RonL
Gold Member
- 1,107
- 219
Rohan2008 said:
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.
- #45
abpud
- 1
- 0
NateD
How is your testing going?
abpud
How is your testing going?
abpud
- #46
gary350
- 274
- 66
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
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
Last edited by a moderator:
- #47
JoeEngineer
- 8
- 0
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.
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.
- #48
RonL
Gold Member
- 1,107
- 219
JoeEngineer said:
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
- #49
JoeEngineer
- 8
- 0
I am surprised no-one has jumped on this one...RonL said:
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?
- #50
gary350
- 274
- 66
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%.
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%.
Last edited:
- #51
JoeEngineer
- 8
- 0
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 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.
- #52
RonL
Gold Member
- 1,107
- 219
JoeEngineer said:
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
- #53
RonL
Gold Member
- 1,107
- 219
RonL said:
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
- #54
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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.RonL said:
In a hurricane, the pressure is lower than atmospheric in the center.
- #55
RonL
Gold Member
- 1,107
- 219
Redbelly98 said:
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.
- #56
JoeEngineer
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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.RonL said: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.
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.
- #57
RonL
Gold Member
- 1,107
- 219
JoeEngineer said:
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
- #58
NateD2
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Hi sorry for the extreme delay in posts. I changed e-mails and forgot the password for NateD as soon as the administrator gets back to me I'll switch back to that name... Until then NateD2 is the same person as NateD.
I status update on my work. For the past year I have been in the process of getting a casting made. Its taken longer then I wanted it to but hopefully it'll soon be ready (I had to make my own patterns for investment casting).
In the mean time I have been working on a 64 Channel Data Acquisition system. At peak I can grab 3,000 samples per second per channel. So any requests for data let me know. I'm hoping I can detect some turbulence above and beyond background noise.
I'll keep everyone posted on that. More to be posted soon.
I status update on my work. For the past year I have been in the process of getting a casting made. Its taken longer then I wanted it to but hopefully it'll soon be ready (I had to make my own patterns for investment casting).
In the mean time I have been working on a 64 Channel Data Acquisition system. At peak I can grab 3,000 samples per second per channel. So any requests for data let me know. I'm hoping I can detect some turbulence above and beyond background noise.
I'll keep everyone posted on that. More to be posted soon.
- #59
JoeEngineer
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NateD2 said:
Nate:
I would be very interested in getting some Data from you. I was working on trying to get a turbine project going as a Senior Design Project for students at CSU- missed the deadline though. I'd love to see some Academic progress made with this turbine!
- #60
NateD2
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I agree most sites out there are bogus. Most of the technical documents I've read are also bogus or seem to be.
I just spent the past year working with actual steam turbines (not TT type). Impingement is a problem around condensation states. But just because there is no impingement (angles) doesn't mean that condensate isn't a problem even for a TT.
In conventional steam turbines water erosion is a problem due to the long operating times water actually washes away the binding atoms in between metal grains leaving a jagged rough looking metal (stainless steel).
So contrary to what has been posted wet steam will be a problem in long term operation of TT turbines.
As to CFD. I have attempted CFD however it appears by me that solving the Navier Stokes equations with all relevant factors included (compressibility, state change, laminar flow (boundary layer) is difficult if not impossible in a situation where the flow is rotational. Now I'm not saying it can't be done... but in my opinion the cost and time effort to "model" a TT flow with CFD isn't worth it. I can design a whole engine, build it and test it for less then the CFD work will cost. Of course if some genius is out there who really understands CFD maybe they can get it all to work. The big barrier is in modeling streamlines and flow equilibrium as well as modeling viscosity as a function of state (temp, pressure, velocity etc..).
If anyone reading this can do it please let me know I'm very interested.
In the mean time real world testing is my best bet.
As to efficiency I project mixed results. One thing that is unique with a TT is the expansion path is not fixed. With the right outlet sides it might very well be possible to extract power from fully expanded flow. However I have my doubts and predict that multiple TT stages are needed to extract all the energy.As to some other practical limits (Disk Mass, Speed, Balance etc..)
Disk Mass is a problem only when proper engineering is not applied to them. A properly designed disc can function within design point and survive.
Balanced discs is a common problem solveable today with proper balance techniques and machines. There are many turbo machines that rotate faster then 25,000 RPM and have no problem. Again it is a matter or proper engineering.
Disc speed is a function and limit of disc size and line pressure and a bit of common engineering sense.
I see no need to gear down at least for most applications.
Disc spacing will most likely turn out to be a complex thing based on a number of factors (which hopefully I will soon have data for).
The Exhaust hole size is a pure myth in some ways. Proper design principles should yield decent efficiency based on a few simple ratios. Additionally tapering the discs would work but from my design point of view prove to be more hassle then they are worth given the goals of a TT.
The guesses made on KE are probably incorrect (I'll claim that once I'm done with testing).
Disk surface finish should be as smooth as possible. But a best practical finish is probably best. Again something an engineer can account for.
"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."
I couldn't agree more. I have spent over 10 years on this project and devoted much time to obtaining some real answers and the more I dig the more convoluted the TT engineering has become. Quite fascinating none the less.
I just spent the past year working with actual steam turbines (not TT type). Impingement is a problem around condensation states. But just because there is no impingement (angles) doesn't mean that condensate isn't a problem even for a TT.
In conventional steam turbines water erosion is a problem due to the long operating times water actually washes away the binding atoms in between metal grains leaving a jagged rough looking metal (stainless steel).
So contrary to what has been posted wet steam will be a problem in long term operation of TT turbines.
As to CFD. I have attempted CFD however it appears by me that solving the Navier Stokes equations with all relevant factors included (compressibility, state change, laminar flow (boundary layer) is difficult if not impossible in a situation where the flow is rotational. Now I'm not saying it can't be done... but in my opinion the cost and time effort to "model" a TT flow with CFD isn't worth it. I can design a whole engine, build it and test it for less then the CFD work will cost. Of course if some genius is out there who really understands CFD maybe they can get it all to work. The big barrier is in modeling streamlines and flow equilibrium as well as modeling viscosity as a function of state (temp, pressure, velocity etc..).
If anyone reading this can do it please let me know I'm very interested.
In the mean time real world testing is my best bet.
As to efficiency I project mixed results. One thing that is unique with a TT is the expansion path is not fixed. With the right outlet sides it might very well be possible to extract power from fully expanded flow. However I have my doubts and predict that multiple TT stages are needed to extract all the energy.As to some other practical limits (Disk Mass, Speed, Balance etc..)
Disk Mass is a problem only when proper engineering is not applied to them. A properly designed disc can function within design point and survive.
Balanced discs is a common problem solveable today with proper balance techniques and machines. There are many turbo machines that rotate faster then 25,000 RPM and have no problem. Again it is a matter or proper engineering.
Disc speed is a function and limit of disc size and line pressure and a bit of common engineering sense.
I see no need to gear down at least for most applications.
Disc spacing will most likely turn out to be a complex thing based on a number of factors (which hopefully I will soon have data for).
The Exhaust hole size is a pure myth in some ways. Proper design principles should yield decent efficiency based on a few simple ratios. Additionally tapering the discs would work but from my design point of view prove to be more hassle then they are worth given the goals of a TT.
The guesses made on KE are probably incorrect (I'll claim that once I'm done with testing).
Disk surface finish should be as smooth as possible. But a best practical finish is probably best. Again something an engineer can account for.
"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."
I couldn't agree more. I have spent over 10 years on this project and devoted much time to obtaining some real answers and the more I dig the more convoluted the TT engineering has become. Quite fascinating none the less.
- #61
NateD2
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Joe Engineer,
Sharing data is a great idea. However it appears very few people have even attempted to properly document the data they get.
How would you go about collecting data?
Sharing data is a great idea. However it appears very few people have even attempted to properly document the data they get.
How would you go about collecting data?
- #62
NateD2
- 11
- 0
Joe Engineer,
What type of data do you want to see collected? I'm sure I have about 5 to 8 extra channels I can put to the task on my Data Acquisition system. I just have to write the C code for the conversions.
What type of data do you want to see collected? I'm sure I have about 5 to 8 extra channels I can put to the task on my Data Acquisition system. I just have to write the C code for the conversions.
- #63
NateD2
- 11
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RonL,
A thermodynamic converter in my opinion is anything that converts thermal energy into some other type of energy. A turbine with generator is a thermal to electrical converter however not a direct one (requires two steps).
Additionally pulling a vacuum happens on any turbine system that I'm familiar with... ore maybe not a vacuum but a relative low pressure. Traditionally this is done on steam turbines with a blower or compressor then the vapor is condensed and fed through a feed pump back into the boiler and then back into the turbine... a simple condenser can act to create a relative low pressure. Often times though a blower is used because the input energy vs efficiency gain is worth while.
A thermodynamic converter in my opinion is anything that converts thermal energy into some other type of energy. A turbine with generator is a thermal to electrical converter however not a direct one (requires two steps).
Additionally pulling a vacuum happens on any turbine system that I'm familiar with... ore maybe not a vacuum but a relative low pressure. Traditionally this is done on steam turbines with a blower or compressor then the vapor is condensed and fed through a feed pump back into the boiler and then back into the turbine... a simple condenser can act to create a relative low pressure. Often times though a blower is used because the input energy vs efficiency gain is worth while.
- #64
NateD2
- 11
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RonL,
Flow is a function of the difference in pressure between high and low... a vacuum can be considered zero pressure for all practical purpose and aids in extracting as much energy as possible.
If my memory serves me Work is defined as the integral of P*dV... or simply the change in volume... in the case of a TT we are talking about 1/density change (I think)... again I'm a bit rusty on all that but I think you get the idea.
Flow is a function of the difference in pressure between high and low... a vacuum can be considered zero pressure for all practical purpose and aids in extracting as much energy as possible.
If my memory serves me Work is defined as the integral of P*dV... or simply the change in volume... in the case of a TT we are talking about 1/density change (I think)... again I'm a bit rusty on all that but I think you get the idea.
- #65
JoeEngineer
- 8
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Nate,
Well, what I was going to propose as a senior design project was a simple, 2 disk test rig with ribbon type housing. You could use a flat nozzle which overshot the disks, then just measure mass flow between them. Essentially I want to design a rig where disk gap, housing clearance, mass flow, even disk camber could me modified relatively easily.
I was hoping to make this a senior design project because that would give access to some of the more expensive, ultra complex analysis equipment out there, available in academia. First thing that comes to mind is some type of particle trace- they used that in my old lab- basically you inject particles, and the machine plots their location producing nice streamlines to verify a cfd model. The other method would be infrared- simply taking infrared high-speed video of the turbine- assuming it was simplified, would give you some interesting data on HX.
Access to those types of machines could be limited- but, similar results could be done with 64 channel data accusition. Just comes down to how many TC's (thermal couples) and PT (pressure transducers) you have. The more you have the better your resolution. If it were me I would probably start by affixing combo TC and PT in a grid on the surface of a modified runner. Of course this means added complexity of routing all your leads through a high-speed rotating connector. And some extra time balancing. Assuming you used very small holes (.5mm or less) you could probably negate any effects from the sensor-
If you removed the housing from one side you could also probably take a series of infrared photos for heat gradient- I have heard of people using of the shelf digital cameras for similar things.
Well, what I was going to propose as a senior design project was a simple, 2 disk test rig with ribbon type housing. You could use a flat nozzle which overshot the disks, then just measure mass flow between them. Essentially I want to design a rig where disk gap, housing clearance, mass flow, even disk camber could me modified relatively easily.
I was hoping to make this a senior design project because that would give access to some of the more expensive, ultra complex analysis equipment out there, available in academia. First thing that comes to mind is some type of particle trace- they used that in my old lab- basically you inject particles, and the machine plots their location producing nice streamlines to verify a cfd model. The other method would be infrared- simply taking infrared high-speed video of the turbine- assuming it was simplified, would give you some interesting data on HX.
Access to those types of machines could be limited- but, similar results could be done with 64 channel data accusition. Just comes down to how many TC's (thermal couples) and PT (pressure transducers) you have. The more you have the better your resolution. If it were me I would probably start by affixing combo TC and PT in a grid on the surface of a modified runner. Of course this means added complexity of routing all your leads through a high-speed rotating connector. And some extra time balancing. Assuming you used very small holes (.5mm or less) you could probably negate any effects from the sensor-
If you removed the housing from one side you could also probably take a series of infrared photos for heat gradient- I have heard of people using of the shelf digital cameras for similar things.
- #66
NateD2
- 11
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JoeEngineer,
I'm not sure I follow exactly what you mean. I guess you are interested in plotting the streamlines. But really all that's needed is some way to know how long a particle is in the case. Putting rotating TCs and PTs on it is very tough at least on the design I have. But if that's what you have in mind I might be able to figure something out. It would have to be a low temp test though but I could probably track everything you need. It would require some special inductive pickup circuitry.
Do you have access to radio interferometry equipment? You can trace particles with radio if you have the right equipment.
In all honesty though the stream lines aren't very important in a TT since they tend to self equilibriate. However I could see them being a subject of academic curiosity. To me what would be important are the inlet variables.
If a streamline model could be established (using something like buckingham pie) you could probably eventually generate a fairly accurate model of the internals and use it to validate CFD.
Feel free to contact me via e-mail. Send me a mail message on here and I'll give you my e-mail address.
Nate
I'm not sure I follow exactly what you mean. I guess you are interested in plotting the streamlines. But really all that's needed is some way to know how long a particle is in the case. Putting rotating TCs and PTs on it is very tough at least on the design I have. But if that's what you have in mind I might be able to figure something out. It would have to be a low temp test though but I could probably track everything you need. It would require some special inductive pickup circuitry.
Do you have access to radio interferometry equipment? You can trace particles with radio if you have the right equipment.
In all honesty though the stream lines aren't very important in a TT since they tend to self equilibriate. However I could see them being a subject of academic curiosity. To me what would be important are the inlet variables.
If a streamline model could be established (using something like buckingham pie) you could probably eventually generate a fairly accurate model of the internals and use it to validate CFD.
Feel free to contact me via e-mail. Send me a mail message on here and I'll give you my e-mail address.
Nate
- #67
JoeEngineer
- 8
- 0
Nate-
Sent you a mail message with my email-
I understand your interest in inlet and outlet geometry- that and the friction on the housing are probably the places where improvement efforts would yield the best results.
My interest in looking at streamlines within the runners- and heat/mass transfer there is to find a baseline for maximum theoretical efficiency. Otherwise its hard to quantify improvement by other factors. There is something very interesting and little understood going on inside those runners- a better understanding of which could improve our thinking on how the inlet and outlet should be designed- or lead to some really cool spin off technologies.
Ultimately- to make real progress this project will probably have to get funded. I've worked with VC folks before- and written DOE grants- First thing they want to know is "why is this technology better than others- and why should we finance it further?" I have read some of Tesla's notes claiming upwards of 90% efficiency- as I am sure many others on this forum have... and that's compelling to me- but that claim needs to be proven, at least in some manor be it theoretical calculations, or the lab experiments I am suggesting.
Sent you a mail message with my email-
I understand your interest in inlet and outlet geometry- that and the friction on the housing are probably the places where improvement efforts would yield the best results.
My interest in looking at streamlines within the runners- and heat/mass transfer there is to find a baseline for maximum theoretical efficiency. Otherwise its hard to quantify improvement by other factors. There is something very interesting and little understood going on inside those runners- a better understanding of which could improve our thinking on how the inlet and outlet should be designed- or lead to some really cool spin off technologies.
Ultimately- to make real progress this project will probably have to get funded. I've worked with VC folks before- and written DOE grants- First thing they want to know is "why is this technology better than others- and why should we finance it further?" I have read some of Tesla's notes claiming upwards of 90% efficiency- as I am sure many others on this forum have... and that's compelling to me- but that claim needs to be proven, at least in some manor be it theoretical calculations, or the lab experiments I am suggesting.
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- #68
JoeEngineer
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I know getting funding is probably going to rub some of the guys funny in this forum-
But as I have stated before- while basic turbine operation is reasonably straight forward- competitive optimization is highly complex. This is not going to get anyone rich quick- if it were that simple someone would have done it long ago.
I feel this is a very promising technology- but not one that is going to get developed by someone selfishly trying to keep profits to themselves. Success will ultimately be a group effort (just like most technology start ups) and eventual profits will be distributed by many. I know inventors hate the idea of others profiting on their ideas, but- a wise person once told me- "its better to have part of something than all of nothing."
But as I have stated before- while basic turbine operation is reasonably straight forward- competitive optimization is highly complex. This is not going to get anyone rich quick- if it were that simple someone would have done it long ago.
I feel this is a very promising technology- but not one that is going to get developed by someone selfishly trying to keep profits to themselves. Success will ultimately be a group effort (just like most technology start ups) and eventual profits will be distributed by many. I know inventors hate the idea of others profiting on their ideas, but- a wise person once told me- "its better to have part of something than all of nothing."
- #69
dr dodge
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Wanted to hear an update on the Ronl saw turbine
that was my idea too
dr
that was my idea too
dr
- #70
NateD2
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Just wanted to post an update to let everyone know I'm still working on things. Right now I'm working on some programming for the data collection.