Author Topic: Homemade wind tunnel...  (Read 12164 times)

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windstuffnow

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Homemade wind tunnel...
« on: November 04, 2005, 11:24:27 PM »
  Well 4 days work, lots of scrap lumber and 100 bux worth of plywood it runs 10.5 mph inside with one fan running....





  It still needs some finishing trim and paint but for the most part the construction is complete.  As well, I still need to build the inlet air straightner.   The second fan motor isn't operational and my controller for the 2hp motor isn't in operational condition.   It had 3 broken mosfets and a smashed plastic high speed rectifier.   I orderd parts for it but it will most likely be another week before the parts get here to repair it.  I found another motor and plan to put it in tomorrow.  That will make it a "one windspeed" unit for now then I'll rebuild the power train to accept the new parts.


  With the single fan running the air inside is amazingly clean even with out the straightner.  I used a smoldering pine stick and watched the air flow and it stays fairly straight past the test area where it makes a quick turn into a swirl toward the outlet through the fan.   I'm pretty happy with the functionality so far, it ain't pretty but for a total of 125 bux invested in it I can't complain.   It stands 5ft tall and is 14 ft long with a test area of 34" high and 46" wide.   That should make a good test area for a 2ft x 2ft unit making it only around a 33% obstruction.  


  I believe the "real" tunnel testing will happen sometime next week, their still testing wings as of today... I'm anxious to see the difference between the "real" and "homebrew" tunnel ( as well as getting some hard numbers from the unit ).


  Lots of  Fun !!!

.

« Last Edit: November 04, 2005, 11:24:27 PM by (unknown) »
Windstuff Ed

BigDogues

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Re: Homemade wind tunnel...
« Reply #1 on: November 04, 2005, 06:35:11 PM »
That is just awesome. I want one! Did you catch my little blurb on making a straightener on the wind tunnel babble thread? Since you need a smaller straightener than I thought you could probably build it using just one sheet of luaon.  
« Last Edit: November 04, 2005, 06:35:11 PM by BigDogues »

electrondady1

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Re: Homemade wind tunnel...
« Reply #2 on: November 04, 2005, 07:31:40 PM »
thou shalt not covet thy neighbours windtunnel!even if it's got a clear observation door!

« Last Edit: November 04, 2005, 07:31:40 PM by electrondady1 »

drdongle

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Re: Homemade wind tunnel...
« Reply #3 on: November 04, 2005, 07:54:57 PM »
Seems a bit small for testing turbine blades, perhaps the picture is misleading........
« Last Edit: November 04, 2005, 07:54:57 PM by drdongle »

rotornuts

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Re: Homemade wind tunnel...
« Reply #4 on: November 04, 2005, 08:56:35 PM »
Scaled models Dr.D.


I'm excited to see you start using a wind tunnel Ed. Calibrated against the "real" tunnel you should be able to start producing some real good info.


Mike

« Last Edit: November 04, 2005, 08:56:35 PM by rotornuts »

adelaide

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Re: Homemade wind tunnel...
« Reply #5 on: November 04, 2005, 08:56:54 PM »
verrry coool ,wonder if u can put mic in for tip testing (noise) and try veribal pich (bolts at least) to find efishancys as well look forarwd to seeing experament results ,what is good bad .i seem to have heaps better talk ec with added on hub bits(plasti and metal glu/screwed) to simular to what blade calc has as results are(wide corde ) hope u test that even on small scale will be verry intersting well done how are u making smoke in tin with tube ,and how can u make alt dump so dosent have bat up down diff may cloud results ,cool if u could modify a house alarm strob to go faster (i have befor 12v) to see some blade flow /seperation point. wonder mif lots blades have more tip loss or 3/2/1 better /maby it can have duct to house for vacume in 1 second hahaha(get cat out first)
« Last Edit: November 04, 2005, 08:56:54 PM by adelaide »

willib

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Re: Homemade wind tunnel...
« Reply #6 on: November 04, 2005, 11:52:07 PM »
Nice job Ed..

i emailed you a pic of my version of your vawt , a while back..

i used 2" pvc as the central axis ..

last winter when i was working on it i froze my a** off testing it.. lol

aside from its slight wobble it worked great..
« Last Edit: November 04, 2005, 11:52:07 PM by willib »
Carpe Ventum (Seize the Wind)

sahlein

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Re: Homemade wind tunnel...
« Reply #7 on: November 05, 2005, 05:45:09 AM »
That really is quite a piece of work.

I did contract work several years ago at NASA Ames Labs in which I did work on

cranes inside some of their wind tunnels.

Many of theirs are in the form of a square using one "blower" which recirculates the air.  Rather like a hollow, squarish donut.

The biggest one I went into would hold a whole medium sized airliner.

In their designs the area behind the test chamber was about twice the cross-section

of the test area it self.  Possibly to get a pressure drop to increase the airspeed?

Just thought I'd throw that out there.

Joe
« Last Edit: November 05, 2005, 05:45:09 AM by sahlein »

monte350c

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Re: Homemade wind tunnel...
« Reply #8 on: November 05, 2005, 06:24:57 AM »
Hi Ed,


Very nice work!


This should make it a lot easier to test all the small changes to see which ones work and which don't.


And you can always use it to keep the shop cool in the summer!


Ted.

« Last Edit: November 05, 2005, 06:24:57 AM by monte350c »

windstuffnow

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Re: Homemade wind tunnel...
« Reply #9 on: November 05, 2005, 12:34:41 PM »
  Thanks for all your comments!  It's been fun buiding it, quite challenging scavanging for pieces of useable lumber and parts.


  Dispite all my efforts to get both fans running today I lost the battle.  I have 5 of those jet fans, 3 still had motors and only one of them is operational.  The other two run but when under load won't come up to speed.  These fans are dated "1969" so I'm probably lucky that one actually ran.


  I guess I'll have to find something else to do until the parts come in.   Don't you just hate it when your finalizing a project and theres some little thing that makes you wait to finish it?  I was really hoping to run a few tests with it this weekend...


.

« Last Edit: November 05, 2005, 12:34:41 PM by windstuffnow »
Windstuff Ed

hvirtane

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Re: Homemade wind tunnel...
« Reply #10 on: November 05, 2005, 01:12:20 PM »
It looks really nice.


I hope that you will get

it fully working soon.

And then we will see results

of testing Lenz turbines

and other stuff...


- Hannu

« Last Edit: November 05, 2005, 01:12:20 PM by hvirtane »

WileCoyote

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Re: Homemade wind tunnel...
« Reply #11 on: November 05, 2005, 06:27:19 PM »
I'm sure you haven't overlooked this but don't forget to add a protective screen in front of your fans.  I forgot and when my first rotor came apart I was lucky, no damage to my fans.  My tunnel uses four 8x8 fans and is much smaller than yours.  The instant feedback that a windtunnel gives me was well worth the effort in constructing.  I'm currently working on a Helical VAWT.  Has anyone ever tried to use an in-wheel electric bicycle motor for a generator?  Electric bikes are common here and I have located a factory nearby which is willing to give me a demo motor.


Since this is my first time to talk to you, I'd like to say "Keep up the good work!"

I particularly like the way you help others, not only with suggestions but also by offering surplus or leftover materiels.  


I live in ZhuHai China now but originally I'm from Illinois.  I am guessing from your pictures and the John Deere you are also from the Midwest.  Am I correct?


al

« Last Edit: November 05, 2005, 06:27:19 PM by WileCoyote »

windstuffnow

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Re: Homemade wind tunnel...
« Reply #12 on: November 05, 2005, 07:45:10 PM »
  Hi Al,

    Actually from the North east... Michigan to be exact.  


    I'm hoping the wind tunnel will do what I need.   Its working good so far.  


.

« Last Edit: November 05, 2005, 07:45:10 PM by windstuffnow »
Windstuff Ed

windstuffnow

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Re: where to put the anemometer?
« Reply #13 on: November 05, 2005, 08:24:07 PM »
  I hadn't given much thought to the anemometer and was thinking of using a small cup type.   But, I'm thinking the cup type may lead to some disrupted air.  It may not be enough to create any problems or major data errors but I'm not sure where it should be placed for an accurate samplings.  I'm using a handheld unit right now.


  I did get the second jet fan running tonight,  I'm laying on the floor of the tunnel taking windspeed readings with the handheld.  I'm getting 18 mph readings from the center to the sides, close to the walls and ceiling it drops down to around 17.  Sitting up in the tunnel the inlet readings are still very consistant.  


  I bolted the small Lenz turbine in place, using a stick  with the handheld taped on I see 15 mph all around the turbine about 2 ft in front of the unit.  


  Well, I had to connect it to the test equipment before I would be happy and I wasn't comming in until I did.  I have a feeling I'm going to be spending a large amount of time playing in the wind tunnel !  So, the initial test (play time) came in as follows:

1.37 amps at 14.4 volts in a 15 mph wind  There is 68.58 watts total that can be collected in a 4 sq ft turbine (not taking in Betz).  It made 19.72 watts charging the battery.  I see a 28.7% overall machine.   If you include the 3 watt loss through the alternator and the 1.92 watts lost in the rectifier then its making 24.64 watts or a blade efficiency of 36%.  Pretty much what I had calculated before when I included my margin of error.  So if you add Betz into the formula then the blade efficiency would be almost 60% of the maximum possible that can be extracted from that wind.  ( 68.58 x .59 = 40.46 ) then ( 24.64 / 40.46 = 60.89%) or ( 19.72 / 40.46 = 48.7% overall of the total possible.


  Still room for improvement!!


.

« Last Edit: November 05, 2005, 08:24:07 PM by windstuffnow »
Windstuff Ed

nothing to lose

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Re: Homemade wind tunnel...
« Reply #14 on: November 06, 2005, 03:19:09 AM »
 That is great. Nice clean job too. Looking forward to hearing how it works when you get your parts.


" I guess I'll have to find something else to do until the parts come in.   Don't you just hate it when your finalizing a project and theres some little thing that makes you wait to finish it? "


Yes, I know that feeling far to well myself and I pity you.

 By the time I get stuff I need my projects get lost or bounced around so much most the time they end up not getting finished till far far to long.

Well look at the bright side yours won't have that problem, a little big be moved around to much or lost :)


 Was that you that posted some of the sterling engine things, was thinking it was. I'll be getting back into those again myself, the water pumper and a couple others.

« Last Edit: November 06, 2005, 03:19:09 AM by nothing to lose »

jmk

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Re: Homemade wind tunnel...
« Reply #15 on: November 08, 2005, 04:44:34 AM »
 Hi Ed,

 Nice work! I to live in Michigan. I live in Oxford wich is about seven miles north of the Palace of Auburn Hills. I was just woundering if you live close?
« Last Edit: November 08, 2005, 04:44:34 AM by jmk »

windstuffnow

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Re: Homemade wind tunnel...
« Reply #16 on: November 08, 2005, 06:36:56 AM »
  In a small town called Vicksburg lower Michigan, not sure where Oxford is... have to look it up.  


.

« Last Edit: November 08, 2005, 06:36:56 AM by windstuffnow »
Windstuff Ed

wayne

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Re: Homemade wind tunnel...
« Reply #17 on: November 08, 2005, 08:31:07 AM »
Hi Ed


Looks very good and thought you could get one of those wireless weather stations at walmart. I have one and works great. I did upgrade my bearings to 3/4" shaft and did test drive but found as I drove up to 10mph it would rock back and forth then finally kick in and spin. My 1/2 scale is 18" dia so might have to mess around with this on weekend. I didn't get any power until 15mph and saw a little charge. I find now were I live and temp drops to -15 c the bearings are really stiff and don't turn as well. Here is a intresting VAWT and don't know how it works.


http://www.opensourceenergy.org/txtlstvw.aspx?LstID=99b82ae5-287f-4bb4-868d-2a44417a564b


Wayne

« Last Edit: November 08, 2005, 08:31:07 AM by wayne »

hvirtane

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Re: Homemade wind tunnel...
« Reply #18 on: November 08, 2005, 01:32:28 PM »
The efficiency of the Lenz turbine

seems to be really good. I expected

that the first prototype would be

around that. When you will develop

it further I think that you will

get it doing still better.


It would be also nice to hear

about a comparison with a

savonius as made according to the

picoturbine 250 W design.


- Hannu  

« Last Edit: November 08, 2005, 01:32:28 PM by hvirtane »

windstuffnow

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Re: Homemade wind tunnel...
« Reply #19 on: November 09, 2005, 07:49:46 AM »
  I built a picoturbine, their 250 watt version which was 2ft diameter x 8 ft tall.  ( still have it as a matter of fact ).   Anyway, I dont have a direct side by side comparison but the Pico made 250 watts in a 35 mph wind and the  Lenz turbine on my roof ( 3ft dia x 4 ft tall ) makes 303 watts in a 38 mph wind.  The alternator that is presently on the roof top Lenz was never intended to make that kind of power and is extreemly inefficient.  In that wind the blade efficiency has dropped to 27% and with the proper alternator I believe it could easily do 500 watts.  


  I'm working on a modified wing for the small test unit which should be interesting.


.

« Last Edit: November 09, 2005, 07:49:46 AM by windstuffnow »
Windstuff Ed

windstuffnow

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Re: Homemade wind tunnel...
« Reply #20 on: November 09, 2005, 08:01:55 AM »
  Looks like a turbine called the Zephyr in canada... they may have some competition on that patent.   It would be interesting to see it in action...  
« Last Edit: November 09, 2005, 08:01:55 AM by windstuffnow »
Windstuff Ed