http://www.reuk.co.uk/Low-Head-Waterwheel-Invention.htm
http://www.beck-mickle-hydro.co.uk/index.php?id=bmh_news
Windspeed
Design is a water wheel on a flex chain! Why in the world would someone waste money on a patent?
Low head go with a Banki turbine. MUCH simpler to home build, efficiency as good. Many fewer parts to fail or wear out.
Have fun, Scott.
Windspeed[ Parent ]
Otherpower has a nice article making Banki turbine.
Most of what I know comes from: http://agungchynta.files.wordpress.com/2007/03/crossflow-turbine.pdf And other studying: http://www.cd3wd.com/CD3WD_40/VITA/BANKITUR/EN/BANKITUR.HTM
Calculating power: http://www.reuk.co.uk/Calculation-of-Hydro-Power.htm Looks like 44 watts
Detail most often missed is the water feeding the wheel requires a Nozzle. A nozzle converts potential energy to kinetic energy. Water pressure should be at Head pressure just before the nozzle. The nozzle area must be smaller than the pipe feeding it.
The dia determines RPM at power, smaller = Faster. For this low heat and power, the smaller dia is important. Shoot for 4 to 6 inches max. Low head, want as small as you can make.
Consider building it out of PVC. The edge of the vanes must be a sharp edge.
Have fun, Scott.[ Parent ]
I have looked at all these sites maths for working out width of nozzle seems to ask for runner outside diameter,how are you to know what this is
Formulas for principal Michell turbine dimensions:
([B.sub.1]) = width of nozzle = 210 x flow -------------------------------------------- Runner outside diameter x [square root] head
= 210 x 2.8 = 9.8 inches.........HOW IS THIS CAN YOU EXPLAIN --------- 12 x [square root] 25
([B.sub.2]) = width of runner between discs - ([B.sub.1]) = 1/2 to 1 inch
= 9.8 + 1 inch = 10.8 inches
Checking your math; using 12" turbine? For this head too large. Expecting turbine to be like 2 foot long. The flow is large, yet the head is small. At 44 watts, turbine will not have much torque on it, using smaller dia should not be a problem.
Maybe this will help you: I came across these years ago, made the error of not keeping a copy. Took Way, way to long to find again:
Spread sheet may help: http://www.planetarypower.com.au/info/microhydro/WalshHydro.xls I did not check this, sheet opened...
http://www.planetarypower.com.au/info/microhydro/crossflow_design.pdf Now have my copies stored on my HDD.
