Some great info here. Question: What effect does the material that the buckets are made of and total weight of wheel have in correlating to loss of effeciency?
Don A. -------------- Original message -------------- > Hi Sergio. > > Some useful links: > > http://www.tev.ntnu.no/vk/publikasjoner/ > A textbook for students on hydro power machinery. > http://www.tev.ntnu.no/vk/publikasjoner/pdf/ArneKjolle/chapter2.pdf > http://www.tev.ntnu.no/vk/publikasjoner/pdf/ArneKjolle/chapter3.pdf > Detailed theory with formulas for many types of turbines. > > http://www.microhydropower.net/ > Good general explanation of the Pelton turbine with pictures. > http://www.microhydropower.net/turbines.html#Pelton > > http://en.wikipedia.org/ > Wikipedia, the free encyclopedia that anyone can edit. > http://en.wikipedia.org/wiki/Pelton_wheel > > http://www.ecoinn.co.nz/ > Very well made runners with plastic spoons, excellent pictures. > http://www.ecoinn.co.nz/product_detail.php?id=58 > > http://www.pressure-drop.com > Software to calculate pressuredrop for all kinds of fluids, pipes, > fittings, nozzles, etc. > You can test it 4 weeks free. If you want use the program after this time > you have to register by the author. > > Pressure-Drop can be used to find nozzle diameter (by trial and error). > (I have not searched for a jet diameter formula based on pressure and flow). > > http://www.du.edu/~jcalvert/tech/fluids/turbine.htm#Impu > Good explanation of Pelton turbine with formulas. > > Summing this up: > Bucket size approximately 2,5 - 4 times jet diameter. > (Too small buckets do not use all the water efficiently, > but too big buckets create more aerodynamic drag) > Water exit angle approx. 165deg (so the water does not hit the back of next > bucket). > The edges where the jet hits the buckets should be sharp to minimize losses. > The spacing between the buckets is made as big as possible, > but not larger than to secure that all water particles will hit a bucket. > > Theoretical velocity of jet: V = sqrt(2gh). (In practice a bit less) > Peripheral velocity of the runner: u (u can take any value from 0 to V) > Maximum power is obtained when u = V/2 (again in practice a bit less) > Theoretical optimum RPM = 60*sqrt(2gh)/(2*pi*D) so in theory D = > 42.3*sqrt(h)/RPM > A "practical" formula I found somewhere is: D = 38.6*sqrt(h)/RPM > considering losses. > Rotor diameter (D) and jet diameter (d) are not related in theory, > but there is a practical limit around D/d = 10, (a large jet will partially > miss a small rotor). > > (A simple solution to find suitable jet diameter for the pressure and flow > you are dealing with, could be to take a conical nozzle from a sealant tube > and experiment with a knife........) > > Best Regards. > > Thor. > -------------------------------------------------------------------- > Thorhallur Ragnarsson Electronics Technician/Instructor > Holtakoti Verkmenntaskolinn Akureyri > IS-641 HUSAVIK Eyrarlandsholti > Iceland IS-600 AKUREYRI > [EMAIL PROTECTED] Iceland > [EMAIL PROTECTED] [EMAIL PROTECTED] > http://www.simnet.is/holtakot http://thor.vma.is/not/thor > -------------------------------------------------------------------- > > > At 17:10 17.9.2005 +0000, kunoserg1703 wrote: > >Hi, it´s the Guatemalan student. I was wondering if any of you can > >help me finding the formulas on pelton design. > > > >I specifically need to know the bucket dimensions, and what is their > >relation with other pelton dimensions. I also need to know the > >relationship between rotor and nozzle dimensions. I have tried to find > >them over the internet, but I could only find the velocity relations, > >and power formula. If anyone can point me to a web page that contains > >the dimensions formulas, or email me them, I would appreciate it. > >Thanx. > > > >Sergio Linares > > > > > > > > > > > > > > > >Does your company feature in the microhydro business directory at > >http://microhydropower.net/directory ? If not, please register free of > >charge and be exposed to the microhydro community world wide! > > > >NOTE: The advertisements in this email are added by Yahoogroups who > >provides us with free email group services. The microhydro-group does not > >endorse products or support the advertisements in any way. > > > >More information on micro hydropower at http://microhydropower.net > > > >To unsubscribe: send empty message to [EMAIL PROTECTED] > >Yahoo! Groups Links > > > > > > > > > > > > > > > > Does your company feature in the microhydro business directory at > http://microhydropower.net/directory ? If not, please register free of charge > and be exposed to the microhydro community world wide! > > NOTE: The advertisements in this email are added by Yahoogroups who provides > us > with free email group services. The microhydro-group does not endorse > products > or support the advertisements in any way. > > More information on micro hydropower at http://microhydropower.net > > To unsubscribe: send empty message to [EMAIL PROTECTED] > Yahoo! Groups Links > > > > > > [Non-text portions of this message have been removed] ------------------------ Yahoo! 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