Presently the KidWind program (www.kidwind.org) uses a 4' by 4' by 4' wind tunnel powered by a 42" barn fan to draw in air to test the model wind turbines designed and built by middle and high school teams to see how much electric energy they will produce in 30 seconds against a 30 ohm load. The tunnels can achieve a wind velocity of about 4 meters per second (about 8 miles per hour).
This project intends to build a wind tunnel the can produce a variable speed wind speed up to 15 meters per second (about 30 miles per hour) to better simulate real world wind conditions. Follow along for the next two months and watch the progress.
So here is a picture of the present wind tunnel size and an example of the blades that would be tested. We want to keep the test chamber the same 4' x 4' x 4' size.
The new tunnel will consist of three parts. The FAN, the CONNECTOR and the TEST AREA shown here in a staged set up. The FAN on the left is a $4,000 600 pound, 72" Mega Storm from J & D manufacturing out of Eau Claire, WI. The fan is driven by a 230v 3HP 3PH motor and is capable of moving 40,000 cfm of air. To visualize 40,000 cubic feet picture for a moment, a kids blow up bounce house the size of your typical 2 car garage. This fan could suck all the air out and flatten the bounce house in 30 seconds!
The CONNECTOR section will be a 4' long tapered tunnel made out of 1/2" MDO plywood. This tunnel will reduce the 6' fan opening on the Mega Storm down to the standard 4' KidWind testing tunnel. You can see how the 4' KidWind standard test chamber has been raised up 1' so that it is centered. A plywood platform will be built to accomplish this.
The first order of business will be to build a holder for the 600 pound fan. Typically this fan would be set into a buildings wall frame and secured there like a window or door. For this application a movable carrier will need to be constructed as shown in the sketch above.
Retractable casters will be installed to allow the fan to be raised for moving and lowered when in place for operation.
The fan came on a shipping pallet and that gave me a pretty good idea for what I would need to build. My plan was to use an engine hoist to lift up the fan, remove the shipping pallet and then roll the fan into my movable carrier. Well guess what? As you will see the problems that cannot be planned for but must be solved for the life of this project.
Building this in an unheated shed with the temperature today at zero in Wisconsin I had to venture out in 2 feet of fresh snow to find 4 concrete blocks to set the shipping pallet on and test the lift out to see if it would work.
After a couple of test lifts I found the balance point for the unit and we are in business. Problem #1 solved.
I am a big believer in mock ups and models to give me clearer picture of what I am designing. This represents the CONNECTOR section. The four 1/2" MDO plywood sections will be hinged to the FAN.
The key to this design is that the four sections of the CONNECTOR can be folded flat for transport and can be set up in a matter of minutes. The tricky part is to have the four frame sections to be at distances that allow for the 1/2" thick of each of the four panels so they fold flat for transport. Note: An empty New Glarus Spotted Cow box represents the FAN unit.
Sealing the joints between the frame on the FAN and 4 CONNECTOR panels will be made by placing a 3/4" foam strip as shown. When the panel is raised the foam will be compressed and seal the joint between the two pieces.
Next up will be the building of the movable carrier and installing the FAN.
No comments:
Post a Comment