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First wind tunnel test.
By Jerry, Section Wind Posted on Thu Jun 25, 2009 at 01:50:44 AM MST
Tested 2 wind generators in tunnel.

I've been talking about building this tunnel for several years now.
I finally got it to a usable stage. There are more improvements to come in the future.
I'll need more power for higher wind speeds. My 5KW 120 volt Variac is rated 41.6 amps.
At full speed I'm seeing about 45 amps through the Variac. Although I've run it a 50 amps for a short run.
I've got some 100 amp auto transformers that will do the trick. That will be latter in time.
The RV shed is open somewhat at both ends so outside winds do affect the tunnel speed abit.
Today I was bucking a 5 to 7 MPH wind. The anamometer is about 2 ft ahead of the wind turbine and centered in the 6X6ft box. The tunnel is 16ft long 6ftX6ft. I also center the wind generator. The wind generator blade is about 1 ft ahead of the wind exit.
Straightners will be added latter to deal with the fan blade turbulance, although its not bad.
The wind comes from 4 each 30inch 4 blade air mover fans. 2 blades each are powered by a 2 HP 180 volt 100 LB DC motor. 2 motors. Today I was powering them at 120 volts. I've powered these well over 200 volts with great success. So there is more top wind speed available.
Top speed without geny in the tunnel was 17.4 mph. 15.4 mph with genny in the tunnel.
Today I tested 2 units. First was my 14-11 ceramic magnet alt. Second was the Hugh Piggot 4 ft single rotor alt.
I've had these 2 units built for over a year now. They've never been flown but they both have had much bench and prime driver time and testing.
Today I used the same blade on both machines. The blade is my plastic 4ft tip to tip "Jerry Blade".
It will be very interesting to see the comparison between my plastic blade and the wood carved 4ft Hugh Piggot blade. At this time I've just got 1 Hugh Piggot wood blade done.
I will retest and post the #s when these wood blades are finished.
Because time constraints I seteled on 12.8 MPH for both machines. The head winds made it hard to get a steady reading at other wind speeds today. I was able to get a fair amount of 12.8 MPH time on both machines.
The L-16 batteries were in bad need of charge. I figured these small gennies and the short time charging on these rather large batteries would mantian a close voltage/load for both units being tested.
The 14-11 was slightly more powerfull then Hughs 4ft. But this was the case when I bench tested both PMAs also.
Hughs 4ft hit 1.5 amps at 12.147 volts at 12.8 MPH for 18.22 watts.
Since the 14-11 ceramic was tested first the startup voltage was lower.
The 14-11 ceramic hit 12.087 volts at 2.5 amps at 12.8 mph for 30.21 watts.
I did see about .75 amp from the 14-11 ceramic at 6.3 mph and saw 0 amps from Hughs 4 ft at 6.3 mph.
Higher TSR blades may reverse these findings? We'll see when the wood blade is finished?
But for now I'm pleased that A wind generator with ceramic magnets, many 3 amp diodes, 28 gage wire with 300 turn coils, with powdered iron in the coil centers, with non star but multipul single phase Jerry Riged and plastic blades is preforming this well.
But much, much more testing to be done.
Here are a few pictures.

Thats it for now. Back to the lab.
Jerry

First wind tunnel test. | 19 comments (19 topical)

Re: First wind tunnel test. (3.00 / 0) (#1)
by Jerry on Wed Jun 24, 2009 at 08:19:39 PM MST

A couple corrections are in order. Its 24 gage wire not 28 gage and it 400 turns per coil not 300.

Sorry bout that.

You can see the build and bench testing of both alts in my diary. Lots of pictures there too.

I'd like to thank Flux for the insperation on these units. He said it would be hard to beat the preformance of the Hugh Piggot 4ft machine. But it aint over yet the wood blade may change everything? The 14-11 may just come in a close second but right now its ahead a littel?

Jerry

Airheads Page

Re: First wind tunnel test. (3.00 / 0) (#2)
by Jerry on Wed Jun 24, 2009 at 08:27:16 PM MST

Forgot to mention, I'll be testing pipe blades also (ZubWoofers ect).

I'll be tersting GE ECMs, the Garbogen, Ameteks, tredmill motors, The Hornet, Air-403, F&P, a small NEO dual rotor and a few other units.

I'll be very busy this sommer. I'll post all the #s.

Jerry

Airheads Page

[ Parent ]

Re: First wind tunnel test. (3.00 / 0) (#3)
by Basil on Thu Jun 25, 2009 at 05:01:21 AM MST

Great work Jerry. I can't wait to see all the test results.
If you are taking request. I would like to see what a 38 volt Ameteks will do.
You have started something now. Good luck with the testing.
Bad luck or none at all.

Re: First wind tunnel test. (3.00 / 0) (#4)
by electrondady1 on Thu Jun 25, 2009 at 06:04:24 AM MST

jerry ,
do you ever find yourself humming "i did it my way" ???

[ Parent ]

Re: First wind tunnel test. (3.00 / 0) (#11)
by Stonebrain on Fri Jun 26, 2009 at 05:33:14 AM MST

For testing an alternator,you don't need a windtunnel.
run it at different rpm's etc;

On the other hand if you know enough about the alt,you can use the windtunnel to choose the blades that matches the alt.

I mean if you test the alt with the wrong blades in a windtunnel you might think it's bad and if you test it with the right blades it might turn out good.

Testing an alt is not the same as testing blades.
Hope you understand what I mean,

cheers,
stonebrain

[ Parent ]

Re: First wind tunnel test. (3.00 / 0) (#15)
by Jerry on Fri Jun 26, 2009 at 09:55:13 AM MST

Hi stonebrain.

As far as blades matching the alt. This is why I sugjested that although the 14-11 is preforming better then Hughs 4ft right now, that could change once Hughs 4 ft is fitted with the wood blades he has designed for hie alt.

Hope to get those carved soon. I'll be testing some ZUB/Woofers and some foam pipe blades as well.

Neet thing about the tunnel, you can test all kinds of alts and blades.

Jerry

Airheads Page

[ Parent ]

Re: First wind tunnel test. (3.00 / 0) (#5)
by Capt Slog on Thu Jun 25, 2009 at 08:20:12 AM MST

Wow Jerry, you must be keen to build something like that. Have you considered fitting some louvres just down from the famns to make the airflow really straight? Overkill obviously unless you want to use it later to look at streamlining. It will be interesting to see the results whatever.

All you need to do know is say that turbine is running the fans and the post will disappear! ;-)

.
"Slowly changing the world, one watt at a time!"

Re: First wind tunnel test. (3.00 / 0) (#7)
by Jerry on Thu Jun 25, 2009 at 09:57:40 AM MST

There has been discusion of straightners to deal with the fan blade turbulance.

I'm thinking of using concrete form tubes. The big box home improvement stores have thin wall (1/8") tubes at 6", 8", 10" and 12" diameters at 4ft long.

I think a stack of these at the center mark would do the job. I'm thinking the 12" should work. Problem is that might be several $100 and I havn't got the funds for that.

I'll have to get creative and find a cheap way to do the straightning?

Not sure if I have an Ametek 38 volt. I do Have the older 7" long 50 volt though.

After I've fully tested the AIR-403 and the Hornet I will sell them fiarly cheap.

I baught them a few years back during my newby learning time. Then I found out home built was better.

If this group dosen't mind I'll report test #s with these diferant units as time permits?

The Oregon Scientific anamometer is nice but ony give a reading in the gust mode every 10 seconds.

I have a small hand held anamometer that seems very acurate. It reads the same as the Oregon unit during steady wind tests.

This small hand held gives fairly instant readings. I'll mount it in the tunnel and point a small TV camera at it. With a monitor at the metering station I'll be able to take instant MPH, volts and amps photos for freez frame real time readings.

I'll take a sires of photos at given wind speeds for each unit being tested.

Just trying to improve the accuracy.

So there will be upgrades to follow.

Thanks for all the encuragement.

Jerry

Airheads Page

[ Parent ]

Re: First wind tunnel test. (3.00 / 0) (#17)
by Ungrounded Lightning Rod on Fri Jun 26, 2009 at 01:40:22 PM MST

For a straightener: How about collecting a bunch of cardboard boxes, removing the ends, and stacking them up in the middle of the tunnel? This should work until they get wet. B-)

Drop down to your local hardware store: Mine (and Ace) keeps the cardboard boxes out by the big-object pickup area to use for padding trunks and pickup beds when you need to haul something that might scratch or dent.

[ Parent ]

Re: First wind tunnel test. (3.00 / 0) (#19)
by pepa on Sat Jun 27, 2009 at 07:48:45 AM MST

Jerry, try floor covering installers and suppliers, their yard goods come in long round cardboard containers. i have seen dumpsters full of them behind their shops.pepa

[ Parent ]

Re: First wind tunnel test. (3.00 / 0) (#6)
by imsmooth on Thu Jun 25, 2009 at 08:32:36 AM MST

Nice work. This should come in real handy. Maybe you can use it to see what offset angle you need to get the tail to track the rotor directly into the wind, too?
Jonathan

Re: First wind tunnel test. (3.00 / 0) (#8)
by nibor wind on Thu Jun 25, 2009 at 05:48:18 PM MST

Jerry,

Very nice work on the wind tunnel construction. Please realize that you will get more energy out of a wind turbine in your tunnel at say a 15 mph wind then when you have it on a pole in a 15 mph wind. The problem is called wall effect. The basic issue is if the blade interrupts a significant amount of the air it will create a back pressure in the tunnel. This is not true when mounted on a pole. The big boys try and reduce this problem by making their cross section inside the tunnel much smaller then the cross sectional area of the tunnel. So your tunnel may be used for a 2.5" diameter blade. The problem with using scale models of blades is they do not scale like one would think. These issues can really cause some pretty big errors so please me mindful of this.

Good luck,
Michael

Re: First wind tunnel test. (3.00 / 0) (#9)
by Jerry on Thu Jun 25, 2009 at 08:30:43 PM MST

Thanks for the input Michael. This is just the kind of info I need. I welcome all ideas.

Once a unit is tested and then goes up on a tower the 2 diferant inviorments can be compaired at the same wind speed.

It is intresting to compair gennys against each other with same blades or compair same alt with diferant blades.

I've done many wind tests with a mast mounted in the bed of my S-10 PU. Then I used the speedometer for MPH.

I feel this setup is more accurate then that.

I just tested the small hand held anamometer and a small B&W TV camera. Image looks prety good.

This will make for faster more accurate MPH readings.

It may not duplicate real world preformance but it will compair 1 unit to the next under the same and controlable conditions.

Thanks again.

Jerry

Airheads Page

[ Parent ]

Re: First wind tunnel test. (3.00 / 0) (#10)
by Stonebrain on Fri Jun 26, 2009 at 04:46:01 AM MST

Hi Jerry,
Amazing realisation you have there.
With all the funky stuff you make you're awfully productive.

About your windtunnel,
to make it a bit more 'scientific',I think you have to mesure tsr against load.

So you have to mesure rpm of the blades and instead of a battery you should have a kind of resistor bank to vary the load.

So,with the amps mesured and the total resistance(genny included)you know the power the blades are making at different rpm's and loads.
Even more accurate would be mesuring the torque(instead of amps and resistance)

just a few thoughts as far as my understanding goes...

cheers,
stonebrain

Re: First wind tunnel test. (3.00 / 0) (#14)
by Jerry on Fri Jun 26, 2009 at 09:46:26 AM MST

Hi stonebrain.

I have made some amp, volts RPM, FT/LB tourque measurments on the bench.

Could some of this info be aplied to the unit being tested?

I can do some RPM testing in the tunnel as well. A torque test in the tunnel might be a littel more then I wan't to do right now, it would be a bulky messy setup.

First thing is to get the upgrade on the MPH testing.

For right now, compairing blades to blades serves my goal. Since the blades will powering the same alt under the same conditions, the best blade for that unit will be found.

I understand that a blade that works best for 1 alt may not be the best blade for another alt.

Thanks for the input. This gives me more parameters to concider.

Jerry

Airheads Page

[ Parent ]

Re: First wind tunnel test. (3.00 / 0) (#18)
by Ungrounded Lightning Rod on Fri Jun 26, 2009 at 01:47:03 PM MST

Average (not RMS) current and torque should map directly. You can use your bench measurements as an amp/ft-lb calibration and use an averaging ammeter (most analog meters are averaging) to estimate torque on your machine in the tunnel.

Induced voltage and RPM map directly, too, though the voltage drop from the current and wiring resistance confounds that and needs correction if you want to measure it under load. RPM and frequency also map directly. (You might use a tach/dwell meter intended for adjusting point-type ignition systems.)

[ Parent ]

Re: First wind tunnel test. (3.00 / 0) (#12)
by Airstream on Fri Jun 26, 2009 at 07:52:36 AM MST

Wow - 6 x 6 ...

How about using wine-champagne bottle cardboard packing, the interlocking dividers from cases of wine for a mid-tunnel flow vane set? Its precut, stiff, and the local retail stores could come up with enough in a day or three.

A stapler or even a large sewing needle and twine or even small ty-wraps to stitch it together... a bottle of white glue & a $1 gallon of mis-match paint from the local home improvement store to glue and stiffen it up and protect from humidity softening the temper, a razor knife...

If the looks of 15 mismatch box sleeve sets don't 'do' it for you the same thing from refrigerator box cardboard, or even aluminum siding pulled off and on its way to the recycling yard would be a low cost start; you could 'borrow' the trash siding with the promise to return it when you're finished so the contractor isn't out any money and they won't you stomping the siding flat.

If none of the above do it for you - some old fencing and newspaper 'paper-mache' with the above gallon of paint on it would be fairly easy to make a circular & concentric venturi for a mid-tunnel flow equalizer; say an entry cone of 25-30° and exit cone of 5°ish...

The doodle here is just ideas, roufgh detail of venturi on right, etc...

Re: First wind tunnel test. (3.00 / 0) (#13)
by ghurd on Fri Jun 26, 2009 at 09:07:09 AM MST

Along the food packaging line of thought, the big chain restaurants get salad dressing in gallon(?) plastic jars. Think plastic pickle jar. A busy place will go through a LOT of salads in an evening.
Utility knife would cut off the top and bottom leaving a thin wall plastic tube. Something like windshield washer jug material, but heavier.
Red Lobster must have gone through a couple dozen on busy Saturday.
G-
Ghurd.info

Re: First wind tunnel test. (3.00 / 0) (#16)
by boB on Fri Jun 26, 2009 at 11:48:41 AM MST

So, how much power can you generate driving a turbine with this ?

I didn't see the word "watts" in this posting, related to that.
Unless I saw something like 30 Watts ?

boB

[ Parent ]

First wind tunnel test. | 19 comments (19 topical)

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