Hello Robert, Max:
Robert, thank you for coment. I will try to find suitable solution,
that will be able to use affordable materials.
I would ask only one question if it is possible:
What min-max specific speed-Ns should I use?
Max, Thank you for help, but I am working on propeller turbine. Please
read first posts.
--- In email@example.com
, "Simpson, Robert"
> Hi Marko,
> For the head and flow rate you mention, the turbine specific speed
would probably be too high for direct drive to an induction motor as
generator. To bring the specific speed of the machine down to what is
considered an acceptable range for a propeller turbine would mean an
operating speed of somewhere around 300-400 rpm as a rough calculation
unless of course you can achieve a higher head (>0.7m) or decide not
to use all of the available flow rate (<180l/s).
> As far as literature goes, most of the ones I use are older
textbooks, such as Nechleba or a couple of other ones written in
German by Bohl. Again, the theory is for large Kaplan turbines and I
am in the process of simplifying all this for application to the
design of simplified pico-propeller turbines.
> Sorry I can't be of more help at this stage. More to come at a later
> -----Original Message-----
> From: firstname.lastname@example.org
]On Behalf Of acme11_hydro
> Sent: 27 April 2007 00:09
> To: email@example.com
> Subject: [microhydro] Re: Guide on How to Develop a Small Hydropower
Plant Math question?
> Hello Robert
> Sorry for my bed english!
> I noticed your work before two months,very good performed work.
> I have next conditions:
> 1.Head: around 0.70m
> 2.Discharge: around 0.18m^3/s
> Desired setting up:
> 1.propeller installed in plastic elbow pipe, like tubular turbine.
> 2.blades made from flat plate, similarly you did in your project
> 3.directly driven induction motor / generator, 6 or 8 poles
> 4.TSR- tip speed ratio as high as possible
> I do not know how to construct propeller adapted to generator speed:
> 1.blade thickness
> 2.blade angles at inlet and outlet, at known blade number and area
> 3.hub diameter
> 4.guide vanes angle
> Can you tell me, which software or literature can be used for this job?
> --- In microhydro@yahoogro <mailto:microhydro%40yahoogroups.com>
ups.com, "Simpson, Robert"
> <robert.simpson@> wrote:
> > Hi Joel and Marko,
> > I have been working on a research project here at the microhydro
> centre at Nottingham Trent University, UK, on developing design
> parameters for small propeller turbines in the picohydro range (up to
> 5kW) with heads approx. 2 to 5 metres. Over the next few months I am
> aiming to produce a spreadsheet to guide potential designers/
> manufacturers. These turbines have been developed as "appropriate
> technology" for manufacture in developing countries with fixed blades
> and guide vanes, simplified spiral casing and blade designs to save on
> cost and manufacturing complexity. Although the efficiencies are lower
> than more complex designs, the simplifications make them quite
> cost-effective in terms of $/kW for developing countries. Our
> prototype turbine in Peru has a 65% mechanical efficiency (5kW, 4
> metre head) and more information can be found in this pdf newsletter
> (however, the actual article relating to our work is contained on page
> 20-22 of the magazine).
> > http://www.ansyssol
> > As far as the "Guide on How to Develop Small Hydropower Plant", I am
> not familiar with this book or the equations used so cannot comment on
> that directly. I use/ have used other text books on the topic to
> assist in the turbine design, these are usually for much larger Kaplan
> turbines and can be quite theoretical in nature. These however can be
> adapted for use to the design of smaller machines.
> > If there is something more specific you need help with, let me know.
> Hopefully, all going well, I will be able to make available the final
> spreadsheet I develop and gather comments back from interested people.
> > regards
> > Robert Simpson
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