Thanks a lot Nando !! I will be building a prototype of the system . I will build my own turbine I saw where someone mentioned actually making a turbine from bamboo . I beleive the effeciency will be considerably lower than if I had used a commercially available product. I will keep you updated
--- HYDRO <[EMAIL PROTECTED]> wrote: > Wayne: > > The velocity of a flowing water is determined by the > head ( the difference > between to heights when the water is piped between > both points). > > The water velocity = meter/sec= squreroot( 2 * > Head(meter)*9.81(gravity)) > > GROSS WATTS = Volume(liter/sec) * Head(meter) * > 9.81(gravity) > > Then you need to multiply by the efficiencies of the > turbine and the > generator to reach the final output power that for > small hydros, it looks > around 0.6 to 0.7 total efficiency multiplying > factor. > > Regards > > Nando > > > ----- Original Message ----- > From: "wayne burton" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Sunday, October 16, 2005 3:25 PM > Subject: Re: [microhydro] Re: direct drive of > centrifugal pump by a turbine > > > > > > Hello ! > > Does anyone know how to increase the > velocity/force of > > flowing water without using a pump ? > > I need to create sufficient force to turn a > turbine ? > > I know without saying what kind of turbine it > might be > > a bit hard to give the best solution I just need a > > general solution any available theory application > > --- Joseph Hartvigsen <[EMAIL PROTECTED]> wrote: > > > >> Nandi, > >> I've recently built a turbine and helped a fellow > >> select a pump for > >> direct drive from the turbine. I haven't heard > yet > >> how it worked. In > >> principle there are a couple of issues to > consider. > >> First, a > >> centrifugal pump, unlike most generators, has a > >> specified direction of > >> rotation. With a Pelton, there is no issue as it > is > >> symmetric and can > >> be flipped over to change the direction of > rotation. > >> A turgo on the > >> other hand can also be turned over, but it > changes > >> the jet entrance > >> and exit faces. In the case of the turbine I just > >> built for this > >> application this meant that the jet exit needed > to > >> be on the pump > >> side. Normally I would prefer the other way so > that > >> it is easier to > >> keep water off the pump bearings. A Pelton will > >> deflect water toward > >> the pump bearings no mater which direction of > >> rotation is required. > >> > >> The other factor is matching the torque vs. rpm > >> curves of the pump and > >> turbine. With a pump, the torque increases with > rpm. > >> With a turbine, > >> the torque is highest at 0 rpm and decreases to 0 > >> torque at freewheel > >> rpm. Somewhere in the middle the two curves > >> intersect. That will be > >> the operating point. You need to match the > turbine > >> to the pump so that > >> that point of intersection is also at the peak > power > >> rpm of the > >> turbine. This rpm should also be a point > compatible > >> with matching the > >> pump's output head and flow to that required by > your > >> application. > >> > >> The torque/power vs. rpm for the turbine can be > >> computed with a > >> momentum balance. I have such a spreadsheet for > any > >> impulse turbine on > >> my web site. Unfortunately, it is setup only for > >> units of hp, ft-lb, etc. > >> See http://h-hydro.com/turgo_drive.html near the > >> bottom of the page > >> > >> Most pumps are designed to be driven by an > electric > >> motor at 3600 or > >> 1800 rpm (assuming 60Hz, or 3000/1500 rpm at 50 > Hz). > >> You should be > >> able to obtain a pump curve from the > manufacturer. > >> These pump curves > >> will likely be at 3600 or 1800 rpm. To scale to a > >> different rpm, what > >> is knows as "turbomachinery affinity laws" are > used. > >> These laws help > >> scale a geometrically similar design to a larger > or > >> smaller size, or > >> scale the performance of a fixed unique device as > >> head, flow, rpm, > >> power, etc. need to be changed. In the recent > case I > >> helped with, he > >> was eventually able to find a 1200 rpm pump that > >> matched his needs, > >> but it was a custom industrial pump. > >> > >> This link has some info, but you can google > >> "turbomachinery affinity > >> laws" and find dozens of referrences. > >> > > > http://caltechbook.library.caltech.edu/22/01/chap1.htm > >> For the same pump run under different conditions > "D" > >> or the > >> characteristic diameter (usually the impeller or > >> runner diameter) is > >> fixed, and flow varies with rpm (double rpm > doubles > >> flow capacity), > >> Head varies with rpm^2 (double rpm = 4x head) and > >> the same for torque. > >> Power varies as rpm^3. So if you have a pump > rated > >> at 1800 rpm and run > >> it at 1400 rpm, its flow is reduced to 78%, head > & > >> torque to 60% of > >> the 1800 rpm value, and power is reduced to 47% > of > >> the rated power. > >> > >> > >> Joe > >> > >> > >> --- In [email protected], "S.N.Group of > >> Companies" > >> <[EMAIL PROTECTED]> wrote: > >> > > >> > hi all!!!! > >> > > >> > > >> > has any bodythought of using turbines to drive > >> centrifugal pumps > >> > directly?? > >> > we are currently working on a concept wherein > the > >> turbine shft will be > >> > directly connected to the drive shaft of a > >> centrifugal pump . providing > >> > flow all year round . > >> > any help in this matter is solicited. > >> > > >> > regards, > >> > nandi > >> > > >> > >> > >> > >> > >> > >> > > > > > > > > > > __________________________________ > > Yahoo! Music Unlimited > > Access over 1 million songs. 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