Author Topic: 5kw Poncelet Wheel Project  (Read 149401 times)

0 Members and 6 Guests are viewing this topic.

SparWeb

  • Global Moderator
  • Super Hero Member Plus
  • *****
  • Posts: 5452
  • Country: ca
    • Wind Turbine Project Field Notes
Re: 5kw Poncelet Wheel Project
« Reply #297 on: February 06, 2018, 10:00:51 PM »
Sleep easy - bearing failures more often result in destruction of the races and and housings long before complete loss of the wheel  :P

Quote
Do people's solar panels keep them up at night worrying?
Yeah, we all have crosses to bear.
Lightning strikes are a threat to solar panels and wind turbines alike.  I never want to see that, so I ground the heck out of my tower.

Forgive me for not reading back to the beginning - what's the sheet thickness of your wheel blades?  While a smooth curved blade is better, a suitable approximation is numerous small shallow bends.  An inexpensive way to bend sheet into a "french curve" is to make slight bends numerous times, but space each succeeding bend a little closer together.  I have done this on a 20Ton press.  The slots you welded the blades into are a different matter, but I think making a template could simplify that curved cut, too.
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

MattM

  • Hero Member
  • *****
  • Posts: 1167
  • Country: us
Re: 5kw Poncelet Wheel Project
« Reply #298 on: February 07, 2018, 12:19:52 AM »
well, there are horizontally mounted blades and they all suffer the same problem.  Succeeding blades block the preceding blades.  If only we could allow current to flow by the blades without that.  It would look more perhaps like a screw.  if you think two-dimensional curves are difficult, image them in a third and on a curve.  The real trick IMHO is to deflect water outside the radius of the blade to form a path in the opposite direction flow goes through the blade.  You need a yin and yang effect.  Can't expect to intentionally deflect water one direction without an equal and opposite effect in the other, right?  I know, it's all theory.

Mary B

  • Administrator
  • SuperHero Member
  • *****
  • Posts: 3169
Re: 5kw Poncelet Wheel Project
« Reply #299 on: February 07, 2018, 09:06:28 PM »
You could make some curved oak blocks(would have to play with the curve) and use a positive and negative to stamp a blade. There will be spring back so the curve will need to be more than the final curve. Once you have a blade you can use that for the mounting template then make a bunch more.

Harold in CR

  • Hero Member
  • *****
  • Posts: 564
Re: 5kw Poncelet Wheel Project
« Reply #300 on: February 08, 2018, 12:28:23 PM »
I built 2 undershot wheels, similar to Skid's design, using split in 2 pieces of 4" capped PVC pipe, 11 inches long. After doing this, I realized the same effect of preceeding blades using all of the water force, while the receeding blades would be causing drag.

 My idea was/is, to design a curved pan from aluminum, to channel the stream under but raised, so to speak, causing the water to follow more of the blades before exiting the wheel. I can't see any reason this would not produce better results. This could possibly reduce the slap of the blades as they enter the water, also. ?

 Anyone doesn't understand my idea, speak up, and others are open to shoot down my idea. This may aid Skid in better efficiency.  In a controlled powerhouse, a curved chaseway would be formed in the concrete during construction.

Rainwulf

  • Newbie
  • *
  • Posts: 20
  • Country: au
Re: 5kw Poncelet Wheel Project
« Reply #301 on: February 09, 2018, 03:04:09 AM »
Poncelet's curved blade design incorporated a constantly decreasing radius curve. It was less curved at the outer diameter, and more curved at the inner diameter, like the outside of a French curve template.
Ideally this is the way I would have built the blades. However, the shop that curved the aluminum blades wasn't capable of that, at least not without spending a pile of money.

The wheel is still running on the roller bearings. Maybe there is nothing wrong with them? I've ordered the wood bearings and they crossed the border from the US. Hopefully I'll get them sometime soon. I sometimes lay awake at night thinking the roller bearings will fail and the wheel will fall into the river and get washed away forever :( :o :'(  Do people's solar panels keep them up at night worrying?

Not my solar panels, no... i lay awake at night thinking about how to reduce cycle depth on my flooded lead acid batteries!

skid

  • Full Member
  • ***
  • Posts: 207
  • Country: ca
Re: 5kw Poncelet Wheel Project
« Reply #302 on: February 19, 2018, 11:32:37 AM »
The waterwheel is still chugging away on its roller bearings. I ordered new lignum vitae wood bearings and they arrived, but were built incorrectly despite giving the manufacturer clear instructions on what I wanted.

I called the manufacturer and they have built the bearings correctly this time. This time they provided a picture before sending them out.


keithturtle

  • Full Member
  • ***
  • Posts: 224
  • Country: us
  • Things that fly
    • aftertherapture
Re: 5kw Poncelet Wheel Project
« Reply #303 on: February 28, 2018, 01:04:25 AM »
Maybe a simple peristaltic pump could provide a steady flow of water to lube them

Turtle
soli deo gloria

machinemaker

  • Jr. Member
  • **
  • Posts: 53
  • Country: us
Re: 5kw Poncelet Wheel Project
« Reply #304 on: February 28, 2018, 11:33:57 AM »
just another thought on getting water to the bushings, a spiral tubing pump. (http://www.builditsolar.com/Projects/OddProjects/odd_project_refs.htm)
kent

skid

  • Full Member
  • ***
  • Posts: 207
  • Country: ca
Re: 5kw Poncelet Wheel Project
« Reply #305 on: March 03, 2018, 08:48:09 PM »
just another thought on getting water to the bushings, a spiral tubing pump. (http://www.builditsolar.com/Projects/OddProjects/odd_project_refs.htm)
kent

A spiral pump for irrigation was my original idea when I first started to contemplate building my wheel. I'd have to drill the axle shaft for that to work though. Another thing to worry about would be freezing in the winter when the wheel isn't operating.

To lubricate the wood bushings I can probably get away with drilling a few strategically placed 1/2  inch holes in the top of the bearings. There's enough water dripping from the wheel to keep them lubricated I think. I've also thought of putting a collector funnel on the bearing to direct dripping water into the holes in the bearing. I'll figure out something ;)

It's still running on the roller bearings though. I've been giving them a squirt of grease every couple of weeks and they seem fine for now.

MattM

  • Hero Member
  • *****
  • Posts: 1167
  • Country: us
Re: 5kw Poncelet Wheel Project
« Reply #306 on: March 05, 2018, 07:12:04 AM »
Collecting drips would certainly involve the least amount of energy.  Is. There any scenario where the wheel wouldn't drop enough?

skid

  • Full Member
  • ***
  • Posts: 207
  • Country: ca
Re: 5kw Poncelet Wheel Project
« Reply #307 on: March 07, 2018, 07:32:12 PM »
Collecting drips would certainly involve the least amount of energy.  Is. There any scenario where the wheel wouldn't drop enough?

That's a good question that I don't have an answer to. The manufacturer said the wood bearings should last 20+ years if given a bit of water. At some point I will be adding more blade area and I'll make sure I get lots of water dripping on the bearings

Mary B

  • Administrator
  • SuperHero Member
  • *****
  • Posts: 3169
Re: 5kw Poncelet Wheel Project
« Reply #308 on: March 07, 2018, 08:07:54 PM »
Could add some small cups on the sides that scoop then dump over the bearing funnel

hiker

  • Hero Member
  • *****
  • Posts: 1661
  • BIG DOG
Re: 5kw Poncelet Wheel Project
« Reply #309 on: March 08, 2018, 01:02:01 PM »
well if the water is destroying your bearings...might as well make the water lube the bearings...strange you can't find waterproof bearings for that...Just wounder how long wood bushings will hold up. ?
WILD in ALASKA

paara

  • Newbie
  • *
  • Posts: 18
  • Country: no
Re: 5kw Poncelet Wheel Project
« Reply #310 on: March 08, 2018, 11:54:57 PM »
That sounds too good to be true. But i hope the bearing will work for longer then your first bearing.

Quote

That's a good question that I don't have an answer to. The manufacturer said the wood bearings should last 20+ years if given a bit of water. At some point I will be adding more blade area and I'll make sure I get lots of water dripping on the bearings

hiker

  • Hero Member
  • *****
  • Posts: 1661
  • BIG DOG
WILD in ALASKA

skid

  • Full Member
  • ***
  • Posts: 207
  • Country: ca
Re: 5kw Poncelet Wheel Project
« Reply #312 on: March 10, 2018, 12:49:56 PM »
https://www.powertransmission.com/news/6256/Revolvos-Water-Wheel-Bearings-Improve-Efficiency-and-Reliability/

Thanks for the link Hiker! Those are similar to what I have now, but probably have a better sealing system

With regards to Lignum Vitae wood bearings, they are used on industrial MW sized hydro turbines and have a very good track record over the last century. They are used on some submarines too! The key is to keep them wetted and keep sand out.

I'm still running on the second set of roller bearings I installed a couple months ago. I made sure I pumped lots of grease into them, the seals were fitted properly, and the retainers were locked. They seem fine so far and I won't bother changing them out until they fail.

I received my second set of new bearings. The wood is beautiful, and the manufacturer did a very professional job of machining them. The wood is from Mexico, and they were manufactured in Germany by an American based company. At least that's what I understand from all the protected species paperwork.

The wood is so heavy it won't float in water. 8)

skid

  • Full Member
  • ***
  • Posts: 207
  • Country: ca
Re: 5kw Poncelet Wheel Project
« Reply #313 on: May 15, 2018, 11:30:38 AM »
Well the second set of roller bearings were on their way out so I finally installed the wood lignum vitae bearings. Hopefully I don't have any more bearings problems as it was a long day to replace everything.

See video - https://www.youtube.com/watch?v=J2L2rXldOLg

The water wheel is not very efficient presently. When I get some more down time I will close off the interior part of the blades as all kinds of energy is being wasted by not capturing the water that is being forced into the middle of the wheel.

Bruce S

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 5370
  • Country: us
  • USA
Re: 5kw Poncelet Wheel Project
« Reply #314 on: May 15, 2018, 03:09:22 PM »
That is one very impressive setup.
Honestly, once I saw the water my brain went straight to KAYAK  :)
I saw the output in watts. It'll be interesting to see it once the new bearing setup loosens up.

Cheers
Bruce S
A kind word often goes unsaid BUT never goes unheard

Mary B

  • Administrator
  • SuperHero Member
  • *****
  • Posts: 3169
Re: 5kw Poncelet Wheel Project
« Reply #315 on: May 15, 2018, 05:37:14 PM »
Still think this ranks up at the top 2 projects on here. Chris and his chain drive gearbox setup was another one that was really good!

ontfarmer

  • Full Member
  • ***
  • Posts: 198
  • Country: ca
Re: 5kw Poncelet Wheel Project
« Reply #316 on: May 15, 2018, 08:20:52 PM »
That is unbelievable the power of that river.   Is it like that most of the year?  I hope those bearings solve that problem.

MattM

  • Hero Member
  • *****
  • Posts: 1167
  • Country: us
Re: 5kw Poncelet Wheel Project
« Reply #317 on: August 03, 2018, 11:08:05 PM »
Updates?

Ungrounded Lightning Rod

  • SuperHero Member
  • ******
  • Posts: 2865
Re: 5kw Poncelet Wheel Project
« Reply #318 on: August 05, 2018, 05:09:21 AM »


The simplest design was used 100 years ago.  Straight blades with slight tilt allow the wheel to rotate with minimal leading edge drag.

Simple yes, most efficient no, according to Poncelet and other engineers. My view is that in this application,  the more blade area the better. Curved blades have more area. If manufacturing would have been easier, I would have made decreasing radius curved blades to better utilize the water that is being washed over the tops of the blades. I'm looking at the possibility of lengthening the blades another foot, as well as going 20% wider on the lengthened portion to maximize efficiency.

For efficiency you want:
 * Curved blades
 * Long enough that the water doesn't go over the inner edge, but falls back in the same passage that it entered.

A continuously tightening curve is nice, but not critical.
The idea is that:
 * The water enters essentially straight on to the blade, attaching rather than creating turbulence.
 * It rises up the curve, using part of its kinetic energy to push against the curved blade, the rest to make it rise up against gravity, trading kinetic energy to potential.
 * Once it's reached its closest to the axle height, it falls back down, again along the curved blade.  This gives the blade a further push while partially suspending the water on its way down.  As the potential energy of height is again converted to kinetic energy of motion (in this case, mostly downward), much of it is transferred to the wheel and little is left in the falling water by the time it reaches the surface.

So the water enters the wheel turbulence free, pushes the retreating wheel forward on its way up and again on its way down, and leaves the wheel moving downward as slowly as practical and forward at about the rate of the wheel's motion, and at a height slightly higher than on entry (which you can think of as either "Bernoulli says slower is higher pressure, pushing the water up" or "the water's moving more slowly than when it entered so it needs a larger cross-section to achieve the same mass flow rate".
 * The kinetic energy in the forward motion is the "Betz limit" mandate of "you have to leave some energy in the fluid to get it out of the way of new fluid bringing additional energy".
 * The higher exit is a loss, as some of the water fights its way uphill to leave.  This is also part of the Betz limit "Energy left in the fluid to get it out of the way", corresponding to the spreading of the widening of the streamlines of the slowed wind downstream of a mill.
 * Turbulence and friction are also losses, though these can be made small.

So a smooth curve, with the entrance tangent to the incoming water, an exit moving at the mill's spin rate,  and the water staying between the blades and flowing smoothly, is a high efficiency device, because the water leaves with little energy and most of the difference between that and the input energy is converted to shaft horsepower rather than turbulence, friction, or other losses.
« Last Edit: August 05, 2018, 05:18:10 AM by Ungrounded Lightning Rod »

skid

  • Full Member
  • ***
  • Posts: 207
  • Country: ca
Re: 5kw Poncelet Wheel Project
« Reply #319 on: August 07, 2018, 09:09:40 PM »
Updates?

The bearings are working problem free. I think this will be a long term solution. One issue I am now having is belt slippage under high loads. I have 3 V belts but water plus high torque is creating slippage once I start getting up higher in the output range. My temporary solution is to lift the wheel higher up so it creates less power.

Ideally I'd like to build a 10 rpm generator to attach directly to the axle of the wheel and eliminate speed increasers. I've been looking around the internet a little to get some ideas on how to build a custom generator, but really I have no idea of the details on how to go about this. How many magnets/coils/wraps/wire size/etc. are required are a mystery so far. I was thinking that the 60 inch diameter large pulley would be a good rotor to attach magnets to, but I have no idea of the engineering requirements to get my desired output and rpm.

Lightning Rod,
I agree with your post and at some point will take steps to achieve this. Right now my blades are not long enough so I am losing power through inefficiency. A moot point at this time since my generator belts are slipping at high outputs already. At some point I will add 1 foot diametrically to each blade, and make the blades another 10 inches or so wider. 1st I need to solve the generator issue now...

ruddycrazy

  • Hero Member
  • *****
  • Posts: 517
Re: 5kw Poncelet Wheel Project
« Reply #320 on: August 07, 2018, 11:29:21 PM »
Just make a Zubbly 3 phase motor conversion and mount a rubber disk on the output shaft then mount it so the rubber disk drives off the outer diameter of the wheel.. That way plenty of speed and no pulleys or belts to worry about

SparWeb

  • Global Moderator
  • Super Hero Member Plus
  • *****
  • Posts: 5452
  • Country: ca
    • Wind Turbine Project Field Notes
Re: 5kw Poncelet Wheel Project
« Reply #321 on: August 08, 2018, 12:45:27 AM »
Skid,
When you want to break down the mystery, don't hesitate to ask.
There's also lots of "fluid power" books for mechanical people. 
This isn't nerd stuff; it is a really accessible subject once you decide to get into it.

With the prodigious amount of torque and low speed of your wheel, I don't believe it would be easy to convert a motor and expect it to work at a 1:1 ratio.  I would expect to use speed reduction with any generator.  A custom generator could be realistically expected to reduce the need for speed step-up compared to the one you have, but hard to eliminate it.

Have you investigated toothed belts?
I don't know what cost you can tolerate, but they certainly would increase the torque transfer.
Try this if you are curious:  https://us.misumi-ec.com/vona2/mech/M1000000000/M1002000000/
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

ontfarmer

  • Full Member
  • ***
  • Posts: 198
  • Country: ca
Re: 5kw Poncelet Wheel Project
« Reply #322 on: August 08, 2018, 05:32:58 AM »
I would suggest you look into roller chain drive running in a oil bath case.  Big machinery use these
 " motor road grader in the final drive " they run forever trouble free.  It would be easy to convert
and make use of what you have.  A very efficient  drive.

skid

  • Full Member
  • ***
  • Posts: 207
  • Country: ca
Re: 5kw Poncelet Wheel Project
« Reply #323 on: August 08, 2018, 12:53:03 PM »
Thanks for the options guys.

I've thought about chains and toothed belts. Both would require machining or replacement of my big pulley which would be expensive. And I would still have the issue of maintenance over time. Probably the easiest thing to do at this time is prevent water from the wheel dripping onto the V belts by building a shroud of some sort.

What really interests me is making a custom direct-drive generator using the existing large 5' diameter pulley as the rotor. Unfortunately I can't find any information on how many coils, magnets, windings, etc.  I would need to build a 10 rpm generator. I'm good at making stuff, but the electrical engineering side of this is beyond my current (heh) knowledge.


skid

  • Full Member
  • ***
  • Posts: 207
  • Country: ca
Re: 5kw Poncelet Wheel Project
« Reply #324 on: August 08, 2018, 12:57:16 PM »
Just make a Zubbly 3 phase motor conversion and mount a rubber disk on the output shaft then mount it so the rubber disk drives off the outer diameter of the wheel.. That way plenty of speed and no pulleys or belts to worry about

I've already got the generator. The idea of running a rubber wheel against the outer diameter of the wheel is an interesting thought. There is still a potential slippage issue though as the wheel is wet and the torque is very high. I should mention that the wheel is getting covered with slime (like the slippery rocks in the river) which is affecting torque transfer.

frackers

  • Sr. Member
  • ****
  • Posts: 435
  • Country: nz
  • Picard spits "Hello"
Re: 5kw Poncelet Wheel Project
« Reply #325 on: August 08, 2018, 07:57:19 PM »
I can't remember how you are tensioning the belt(s) but I found that a pinch system works well on wet V belts on my walnut washer

Might be worth looking into
Robin Down Under (Or Are You Up Over)

joestue

  • Hero Member
  • *****
  • Posts: 1759
  • Country: 00
Re: 5kw Poncelet Wheel Project
« Reply #326 on: August 08, 2018, 08:03:25 PM »
10 rpm at how many KW?
My wife says I'm not just a different colored rubik's cube, i am a rubik's knot in a cage.

Harold in CR

  • Hero Member
  • *****
  • Posts: 564
Re: 5kw Poncelet Wheel Project
« Reply #327 on: August 09, 2018, 06:27:01 PM »
There is a way to use the existing pulley system. This winter, when you shut down, you can remove the pulleys and figure what size cog belt would match your pulley diameters. They use a slightly different way to measure this.

 Then, buy a sacrificial belt that will fit around the larger pulley. This belt will be very carefully cut and fit around the large pulley and later, recut to fit around the smaller pulley. Carefully measure or "eyeball" the clearance between the bottom of the "V" and the rim of the pulleys. Use enough but not over do it. Purchase some industrial grade epoxy and spread it all around in the pulley grooves, 1 at a time, and mash the cut belt into the epoxy so that the belt is slightly above the rim of the pulleys. Tape/tie, whatever it takes, to hold the cut ends firmly together until the epoxy sets. Then, remove the belt and proceed to the other grooves as needed.

 Of course, immaculately clean the pulleys for adhesion excellence, and, you could always drill a few holes around the sides and "pin" the epoxy, just for peace of mind.

 This has been done on a smaller scale and there is no reason to spend a lot of money, when this will let you harvest the torque you produce.

skid

  • Full Member
  • ***
  • Posts: 207
  • Country: ca
Re: 5kw Poncelet Wheel Project
« Reply #328 on: August 09, 2018, 11:16:06 PM »
I can't remember how you are tensioning the belt(s) but I found that a pinch system works well on wet V belts on my walnut washer

Might be worth looking into

I really like this idea! Part of the reason for the slippage is the large pulley is so much bigger in diameter than the small pulley so the small pulley (which slips) is only getting 1/3-1/2 diameter contact. By putting a pinch on both sides of the belt I could get more contact and better torque transfer. The only negative thing is that I have read that tensioner systems which press on the back side of the belt can cause more rapid deterioration of the belt due to its bending in the opposite direction.

Off topic - I have 10+ walnut trees. How do you get the husks off the shells? Do you wash them after you remove the outer husks?

10 rpm at how many KW?

I over-estimated the design output of the wheel. Even if I make efficiency improvements I think max output ever would be 4KW.

There is a way to use the existing pulley system. This winter, when you shut down, you can remove the pulleys and figure what size cog belt would match your pulley diameters. They use a slightly different way to measure this.

 Then, buy a sacrificial belt that will fit around the larger pulley. This belt will be very carefully cut and fit around the large pulley and later, recut to fit around the smaller pulley. Carefully measure or "eyeball" the clearance between the bottom of the "V" and the rim of the pulleys. Use enough but not over do it. Purchase some industrial grade epoxy and spread it all around in the pulley grooves, 1 at a time, and mash the cut belt into the epoxy so that the belt is slightly above the rim of the pulleys. Tape/tie, whatever it takes, to hold the cut ends firmly together until the epoxy sets. Then, remove the belt and proceed to the other grooves as needed.

 Of course, immaculately clean the pulleys for adhesion excellence, and, you could always drill a few holes around the sides and "pin" the epoxy, just for peace of mind.

 This has been done on a smaller scale and there is no reason to spend a lot of money, when this will let you harvest the torque you produce.

Another good idea. I've also thought of having a chain sprocket machined up out of steel plate and bolting it to the existing pulley.

ontfarmer

  • Full Member
  • ***
  • Posts: 198
  • Country: ca
Re: 5kw Poncelet Wheel Project
« Reply #329 on: August 10, 2018, 06:58:39 AM »
Two stage drive.
 1  Belt from existing big pulley taking it down to the second pulley that is sized to have adequate belt contact.
 2  Roller chain in oil bath case.