Author Topic: advice on 41inch squirel cage use  (Read 1005 times)

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sparks13

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advice on 41inch squirel cage use
« on: February 03, 2005, 01:21:27 AM »
I purchased a 41 inch diameter squirel cage blower, 21 inches wide, with a 39 inch wooden pulley for the drive belt at an auction. My original thought was to use this solid axel and frame to build an overshot water wheel around it for a home hydro project. My site has 6 feet of head, 30-50GPM flow. Looking over the board, I noted the home built cross-flow turbines, which very much resemble my blower unit, only smaller. I am not good at vector forces, reviewing the references for cross-flow turbines left me with the impression that turbine diameter is important and over-all size is critical for these units. Could my rather large squirel cage be used in a crossflow design? which type is more efficient, the cross-flow or an overshot wheel. Is there any info out there on the size/capacity of the buckets in a water wheel in relationship to flow rates?..thanks..I am a newbie here..the board has been a great find.
« Last Edit: February 03, 2005, 01:21:27 AM by (unknown) »

ghurd

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Re: advice on 41inch squirel cage use
« Reply #1 on: February 03, 2005, 03:41:05 PM »
Well, its been a while so I will take a stab at it.


That is one big puppy!  I have never even seen one that size.  Probably too big for what you have to work with.  It is going to use a lot of power just to turn itself (bearings losses, etc.).  Next is that it will not turn very fast, so it will need geared up, and that is more losses.  I am prone to think something considerably smaller, easier and cheaper would give more power out.


I don't believe you flow and head are very suitable for a cross flow Michell-Banki turbine even close to this magnitude.  I could be wrong.


The water you have is not bad at all.  I wish I had it.  There is potential there.


The best bet would be somthing a lot smaller like this, but stepped up a bit...

http://www.otherpower.com/otherpower_experiments_waterwheel.html


Possibly thats what you saw, but I think it would produce better than fancier, or factory made units.  There is room for improvement I'm sure, pulley ratios, different generator, make all the water entering the wheel, aim the water inside the wheel better toward the fins, close some loose tolerances in the blower... stuff like that.  Cheap and easy.


Compare the 'output' to more expensive (factory) or complex units using the same water conditions.


Another turbine.

http://www.otherpower.com/scotthydro1.html


And the main hydro page by our hosts...

http://www.otherpower.com/otherpower_hydro.html


Go for it!


G-

« Last Edit: February 03, 2005, 03:41:05 PM by ghurd »
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Flux

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Re: advice on 41inch squirel cage use
« Reply #2 on: February 04, 2005, 01:43:13 AM »
You may get something out of your fan as a Mitchell turbine, it will not really work as an overshot water wheel.


It is far from ideal for your water supply, I think you need a rotor about 10" diameter and 6" wide to handle that flow with no more than 20 blades, your fan will probably have many more.


If you copy what Dan has done on the Otherpower site you will be close, perhaps with a narrower nozzle of better shape.


The Mitchell turbine and overshot wheel have similar efficiencies probably about 60% in that size, up to 75 in larger. The turbine will direct drive on to a  low speed alternator and will be far more efficient than a wheel geared op to a similar speed.


Do a Google search on Mitchell and Banki turbines there is a lot of good information but I have lost the references.


You may be able to get about 30W depending which flow rate you have and whether your gallons are American or Imperial.


Flux

« Last Edit: February 04, 2005, 01:43:13 AM by Flux »