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Wind Turbine Building Tips?

  1. Sep 1, 2017 #1
    I'm building a model wind turbine. I'm using thttps://www.vernier.com/products/kidwind/wind-energy/kw-wth3/ as the hub/the base. That's the only kit I'm allowed to use.
    I'm supposed to decide on the blade size, etc.

    THE RULES:
    . Students will will sign up for a time slot and test their own devices in front of the judges. Students will have 30 seconds to set up prior to testing.
    3. The device must pass a GO-NO-GO inspection including a safety inspection to insure no harm or damage will occur. Any unsafe devices WILL NOT BE TESTED and be counted as a disqualification.
    4. The device must meet the following specs:
    • Stand Height: 24 in (must use stand with gear box system provided by GATSA)
    • Maximum blade diameter: 36 in
    • Maximum number of blades: 12
    • 4 Box fans will be used to create a wind tunnel (2 fans on bottom with 2 fans on top). Wind tunnel will be 48inx48inx48in cube open on the back
    • Voltage will be measured using a multimeter attached to the generator leads
    • Student will have three opportunities and the three voltages will be averaged.
    • Award places determined by voltage ranking
    • Ties will be broken by testing efficiency of the wind turbine

    What I need is not a step-by-step of how to build one. I'd appreciate tips and basic principles.
    Thank you for reading.
     
  2. jcsd
  3. Sep 1, 2017 #2

    berkeman

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    Staff: Mentor

    Welcome to the PF. :smile:

    If they are truly just measuring the open circuit voltage output of the generator circuit, there's an easy way to win! But they must be planning on using some sort of load for the generator output, no? What else are you given about the load? It's important to know that. (Quiz Question -- Why?)

    What reading have you been doing about the efficiency of various windmill blade designs? Have they given you any idea of the wind velocity that will be generated in the "wind tunnel" during testing?

    What other rules are there? Are you allowed to build your own "Maximum Power Point" converter circuit for the output of the generator? Do you know what that is?
     
  4. Sep 1, 2017 #3
    I have done something similar in the past, however I am not aware of your current level of understanding of aerodynamics etc. So I will give you this PDF:
    https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&ved=0ahUKEwi0_-CLqITWAhUGY1AKHc3uDYAQFghqMAo&url=http://www.mdpi.com/1996-1073/5/9/3425/pdf&usg=AFQjCNEznBNRj-fWG5MwcGV6lJqiisilNQ

    It throws a fair bit of concepts and words at you but I found it to be a good jump off platform for blade design. In the competition that I did you only had to design the blades and they also awarded points for ingenuity. A lot of people fell behind because there surfaces weren't smooth. So I recommend you hot wire it out of foam and use clear duct tape then you could reinforce it with carbon fibre or wood depending on the diameter. Then again as @berkeman said, 4 box fans doesn't tell us much about the wind speed. Because foam will work fine for 4 on the Beaufort scale but lets say its 10 and we have a problem :nb):biggrin:
     
  5. Sep 5, 2017 #4
    The rules didn't say anything else about the wind speed. They just said 4 box fans. :/

    (Also, please check my reply to @berkeman. It has more information.)
     
  6. Sep 5, 2017 #5
    Like I mentioned before, I'm very new to all of this. I joined on a whim, just to see what I could do. So forgive me for not understanding most of the lingo and jargon that's common in engineering fields.

    So, my first questions would be: what do you mean by 'load'? Like measurement of energy?

    I've being looking around, but most of the material seems to be hard to digest. I'll definitely be looking for more reading material-- I've got a fair bit of reading to do.

    As far as I know, these are all the rules. And I don't know what a Maximum Power Point converter circuit is... I'm sorry, haha.

    I'm sorry for not replying earlier, and I'm even more sorry for not being able to understand a lot of what you're saying. Thank you for all your help!
     
  7. Sep 5, 2017 #6

    berkeman

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    Staff: Mentor

    No need to be sorry at all. You are doing good things to learn more!
    Well, if there is no output load (like a light bulb or something), then the output voltage can be arbitrarily high and not get loaded down. It takes very little energy to power a circuit that boosts the output voltage to very high values. If there is an output load like a light bulb or a resistor, then you are limited in how high the output voltage can go. If you have an output load of Power=1.2W, then your output voltage and current could be V=12V at I=0.1Amp (P=V*I). If they connect a lower resistance load, that will pull down the output voltage.
    Yeah, just look for some basic introductory electronics tutorials for now. That should give you a better background for the basic electrical stuff you will be working with in this project. Here is a link to some basic electronics concepts at Hyperphysics, for example:

    http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ecircon.html

    :smile:
     
  8. Sep 5, 2017 #7

    JBA

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    Just as an exercise, I figure that 4 box fans set in a 4 ft sq box end would have a maximum fan size of 12" or less and for one typical industrial 12" box fan the delivery rate is 1360 cfm; which, for 4 fans in a 4 ft sq duct, as specified, results in a wind speed of just under 4 mph.

    I have no background to judge how this relates to the blade or unit design; but, maybe it would mean more to one of the other members of the forum with more experience in this area; but, to me it would tend to indicate that a broad blade design tending toward a standard house fan blade would be more appropriate than a more standard wind turbine blade design. At the same time this would seem to be a "power" vs "speed" issue as well.

    Any thoughts or comments, anyone?
     
  9. Sep 6, 2017 #8

    JBA

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  10. Sep 6, 2017 #9

    berkeman

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    Staff: Mentor

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