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happyDaisy
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Location: Thimphu, Bhutan
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Calculating Jets for Pelton Turbines

02/08/2010 5:45 AM

Hi everyone, I am an electrical engineer. I would appreciate if anyone could help me with mechanical design of pelton turbine for hydro plant especially calculation of no. of jets.

And please can someone explain to me the velocity triangle of water impinging the jet in simple ways?? I would appreciate.

Thanks.

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Hendrik
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#1

Re: Calculation of No. of Jets

02/08/2010 9:05 AM

good day happyDaisy

The manufacturers usually are better equipped to supply the answers but it is supposed that you want to be prepared when negotiating.

Please give us some indication of the static head, length and size of piping , volume available and requirments to enable someone to give you some typical calculations.

For a start you can work on 90% of the water HP available at the shaft of the turbine.

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phoenix911
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#2
In reply to #1

Re: Calculation of No. of Jets

02/08/2010 11:08 AM

good response.

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happyDaisy
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#3
In reply to #1

Re: Calculation of No. of Jets

02/08/2010 9:57 PM

Hendrik,Good day to you and thank you so much for the prompt reply.

Here is the basic inputs data with which I am working on:

Discharge = 30 cumecs

Net Heat = 820 metres

RPM of turbine ( from turbine selection chart) = 375 rpm (will be optimized later)

From my calculation, I get just one jet, which I am skeptical about. So can you verify further? I need these basic specifications for my feasibility studies. Please, throw some light on it. I would really appreciate.

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Tornado
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#4
In reply to #3

Re: Calculation of No. of Jets

02/09/2010 1:52 AM

Where are you putting this, Angel Falls (and I'm not sure even they have that much head)?

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happyDaisy
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#5
In reply to #4

Re: Calculation of No. of Jets

02/09/2010 2:16 AM

Hi Tornado, it is in Bhutan. We are himalayan country so we have such high head. I know of similar project that had already been constructed with equal head but with larger discharge.

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Randall
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#6

Re: Calculating Jets for Pelton Turbines

02/09/2010 2:55 AM

My apologies if you have already done this:-

Results 1 - 10 of about 23,700 for pelton turbine design with Safesearch on. (0.27 seconds)

There are some very impressive projects out there:-

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happyDaisy
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#7
In reply to #6

Re: Calculating Jets for Pelton Turbines

02/09/2010 5:34 AM

Hi Randall, Thanks. I did scour all over the internet for it. I thought maybe there are some design expert in here who would clear my doubt.

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chrisg288
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#8

Re: Calculating Jets for Pelton Turbines

02/09/2010 10:22 AM

There is a gentleman here who know this stuff. cwarner7_11 It is surprising he hasn't commented already.

Chris
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cwarner7_11
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#9
In reply to #8

Re: Calculating Jets for Pelton Turbines

02/09/2010 5:55 PM

Thanks for the promo, Chris. I am monitoring, but this is a much bigger turbine than I normally work with. Gotta keep track of your limitations...
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happyDaisy
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#10
In reply to #9

Re: Calculating Jets for Pelton Turbines

02/09/2010 10:45 PM

Hi Chris, thank you for dragging cwarner in this discussion and giving me the direction.

Cwarner, please do share your knowledge with me. It might lead me somewhere. I would appreciate, Sir!

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cwarner7_11
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#11
In reply to #10

Re: Calculating Jets for Pelton Turbines

02/09/2010 11:33 PM

Hello, happyDaisy. I am not sure how much help I can be. Most of my work with hydro turbines has been with micro turbine installations- kilowatts, not megawatts. I also pretty much rely on manufacturers to handle the design of the turbine buckets. There is a pretty good Wiki article on Pelton Turbines that I have studied:

http://en.wikipedia.org/wiki/Pelton_wheel

With regards to the number of nozzles, I have always had a preference for multiple nozzles, but that is because I am usually dealing with varying flow rates- by being able to activate or deactivate some nozzles, I can optimize the system for whatever conditions prevail. Having multiple nozzles also help with maintenance. You can expect the nozzles to erode with time- if you can deactivate one for repairs/renewal without shutting the system down, you are ahead of the game...

Here is a book you might find useful:

http://bookboon.com/int/student/mechanics/key-concepts-in-turbo-machinery

Hope this helps...

Charlie
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happyDaisy
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#12
In reply to #11

Re: Calculating Jets for Pelton Turbines

02/10/2010 12:47 AM

Hi Chris, thank you so much for the information and link to that e-book. I will go through it and try to work the problem out.

Thanks.

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chrisg288 (1); cwarner7_11 (2); happyDaisy (5); Hendrik (1); phoenix911 (1); Randall (1); Tornado (1)

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