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Re: [microhydro] Re: 10 & 12 inch penstock question

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  • Max Enfield
    ... 1. I am not promoting my PC software. I had nothing to do with its creation and had to download a free evaluation copy for subsequent purchase like
    Message 1 of 9 , May 27, 2004
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      Dave wrote:
      >
      > I repeat the question, but this time can someone answer it with or
      > without promoting their PC software?

      1. I am not promoting my PC software. I had nothing to do with its creation
      and had to download a free evaluation copy for subsequent purchase like
      everybody else.

      2. The question as you have posed it cannot be answered. It depends on the
      friction coefficient, which is a function of the pipe material and its
      condition. You have yet to tell us what the pipe is made of.

      Regards,

      Max Enfield
      Planetary Power
    • Nando
      DAVE: Specifically : Did you go to the site and down loaded the software and run it to get the answers you want or do you not know how to do it ?. The Basic
      Message 2 of 9 , May 27, 2004
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        DAVE:

        Specifically : Did you go to the site and down loaded the software and run
        it to get the answers you want or do you not know how to do it ?.
        The Basic software is free for you to do your own analysis --- SO DID YOU
        ?>

        Nando
        ----- Original Message -----
        From: "Dave" <got2flyaway2@...>
        To: <microhydro@yahoogroups.com>
        Sent: Wednesday, May 26, 2004 8:29 PM
        Subject: [microhydro] Re: 10 & 12 inch penstock question


        > I repeat the question, but this time can someone answer it with or
        > without promoting their PC software?
        > > > Can anybody help me figure how many gallons per minute will flow
        > thru
        > > > both a 10 inch and 12 inch penstock that is 22 feet long that has
        > a 6
        > > > foot 8 inch head without any turbine? The penstock will have one
        > 90
        > > > degree bend and a 3 foot draft tube. I trying to determine what
        > size
        > > > will be ideal to replace the existing 8.25 inch penstock before i
        > > > size a turbine that sizes the penstock. Thanx
        > > >
        > >
        > > 1.
        > > This now the fifth time since October last year that I advise the
        > group that
        > > SF Pressure Drop 5.0 [available at http://www.pressure-drop.com/%5d
        > makes it easy
        > > to do any pipe friction/pressure drop calculation imaginable.
        >
        >
        >
        >
        >
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      • Martin.Leahy
        Dave, A reasonable flow velocity for these sizes would be between 3 and 8 feet per second, say 5: D feet/s CPM L 10 inch 5 163 1.14 12 1nch 5 235 0.94
        Message 3 of 9 , May 27, 2004
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          Dave,

          A reasonable flow velocity for these sizes would be between 3 and 8 feet per
          second, say 5:

          D feet/s CPM L
          10 inch 5 163 1.14
          12 1nch 5 235 0.94

          D is diameter
          CPM is cubic feet per minute
          L loss of head in feet per 100 feet of pipe

          With these flow rates you have a head loss of a few inches (Lx22)/100.

          Hope this helps,

          Regards,

          Martin Leahy


          -----Original Message-----
          From: Dave [mailto:got2flyaway2@...]
          Sent: 27 May 2004 02:30
          To: microhydro@yahoogroups.com
          Subject: [microhydro] Re: 10 & 12 inch penstock question


          I repeat the question, but this time can someone answer it with or
          without promoting their PC software?
          > > Can anybody help me figure how many gallons per minute will flow
          thru
          > > both a 10 inch and 12 inch penstock that is 22 feet long that has
          a 6
          > > foot 8 inch head without any turbine? The penstock will have one
          90
          > > degree bend and a 3 foot draft tube. I trying to determine what
          size
          > > will be ideal to replace the existing 8.25 inch penstock before i
          > > size a turbine that sizes the penstock. Thanx
          > >
          >
          > 1.
          > This now the fifth time since October last year that I advise the
          group that
          > SF Pressure Drop 5.0 [available at http://www.pressure-drop.com/%5d
          makes it easy
          > to do any pipe friction/pressure drop calculation imaginable.





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        • Joseph Brezner
          Hi Dave, I get about 11,000gpm out of a your pipe without a turbine connected to it. This is not what you want to know. You need to determine how much power
          Message 4 of 9 , May 27, 2004
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            Hi Dave,

            I get about 11,000gpm out of a your pipe without a turbine connected to it.
            This is not what you want to know. You need to determine how much power you
            want to generate and size the turbine and pipe. Also it is important to
            know how much water can be supplied.

            Joe


            >From: "Dave" <got2flyaway2@...>
            >Reply-To: microhydro@yahoogroups.com
            >To: microhydro@yahoogroups.com
            >Subject: [microhydro] Re: 10 & 12 inch penstock question
            >Date: Thu, 27 May 2004 01:29:33 -0000
            >
            >I repeat the question, but this time can someone answer it with or
            >without promoting their PC software?
            > > > Can anybody help me figure how many gallons per minute will flow
            >thru
            > > > both a 10 inch and 12 inch penstock that is 22 feet long that has
            >a 6
            > > > foot 8 inch head without any turbine? The penstock will have one
            >90
            > > > degree bend and a 3 foot draft tube. I trying to determine what
            >size
            > > > will be ideal to replace the existing 8.25 inch penstock before i
            > > > size a turbine that sizes the penstock. Thanx
            > > >
            > >
            > > 1.
            > > This now the fifth time since October last year that I advise the
            >group that
            > > SF Pressure Drop 5.0 [available at http://www.pressure-drop.com/%5d
            >makes it easy
            > > to do any pipe friction/pressure drop calculation imaginable.
            >
            >

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          • markusmeiren
            The Book Pumps as Turbines gives a flow rate of 85.5 l/s for a 250mm pipe (about 12 ) and 138 l/s for 300mm. This produces a head loss of 1% per unit lenght
            Message 5 of 9 , May 30, 2004
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              The Book "Pumps as Turbines" gives a flow rate of 85.5 l/s for a
              250mm pipe (about 12") and 138 l/s for 300mm. This produces a head
              loss of 1% per unit lenght of pipe.




              --- In microhydro@yahoogroups.com, "Dave" <got2flyaway2@y...> wrote:
              > I repeat the question, but this time can someone answer it with or
              > without promoting their PC software?
              > > > Can anybody help me figure how many gallons per minute will
              flow
              > thru
              > > > both a 10 inch and 12 inch penstock that is 22 feet long that
              has
              > a 6
              > > > foot 8 inch head without any turbine? The penstock will have
              one
              > 90
              > > > degree bend and a 3 foot draft tube. I trying to determine
              what
              > size
              > > > will be ideal to replace the existing 8.25 inch penstock
              before i
              > > > size a turbine that sizes the penstock. Thanx
              > > >
              > >
              > > 1.
              > > This now the fifth time since October last year that I advise
              the
              > group that
              > > SF Pressure Drop 5.0 [available at http://www.pressure-
              drop.com/]
              > makes it easy
              > > to do any pipe friction/pressure drop calculation imaginable.
            • Joseph Hartvigsen
              Dave, I normally suggest a pipe sizing rule of thumb to keep the flow velocity in the range of 3-5 ft/sec or 1-1.5 m/sec. However with such a short pipe you
              Message 6 of 9 , Jun 2, 2004
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                Dave,
                I normally suggest a pipe sizing rule of thumb to keep the flow
                velocity in the range of 3-5 ft/sec or 1-1.5 m/sec. However with such
                a short pipe you can usually go higher, but remember you don't have
                that much head to start with. If you go much higher in velocity, the
                entrance and fitting type losses start to be a bigger factor. As
                diameters get larger the pipe roughness (steel vs. concrete vs.
                plastic etc.) becomes less of a factor. My first cut rough guestimate
                would pick a flow rate around 1500 gpm in a 10" pipe and 2200 gpm or
                so in a 12" pipe, but that is very arbitrary and based on my personal
                assumptions and biases in trading off head loss vs. pipe size etc.

                The link below will let you download the spreadsheet I use for such
                things. It runs on Mac or PC as long as you have excel. You'll need to
                allow macros as the "Moody Chart" for pipe friction losses is
                implemented in some visual basic code. It also has runner sizing
                calculations which are irrelevant here.

                http://h-hydro.com/pipedp.xls

                I've added the pipe & draft tube lengths and heads. The gpm & lps tabs
                are independent calculations and I haven't entered your site info in
                the lps tab. The fittings and pipe roughness tabs have tables for
                various fittings and pipe materials.

                Please pay attention to all of your entries, and cross check with
                other calculation methods before cutting metal and pouring concrete.
                The end answer you are looking for depends on constraints and criteria
                that you have not specified to us, but which you'll need to determine
                for yourself somehow.

                Joe


                --- In microhydro@yahoogroups.com, "Dave" <got2flyaway2@y...> wrote:
                > I repeat the question, but this time can someone answer it with or
                > without promoting their PC software?
                > > > Can anybody help me figure how many gallons per minute will
                flow
                > thru
                > > > both a 10 inch and 12 inch penstock that is 22 feet long that
                has
                > a 6
                > > > foot 8 inch head without any turbine? The penstock will have
                one
                > 90
                > > > degree bend and a 3 foot draft tube. I trying to determine what
                > size
                > > > will be ideal to replace the existing 8.25 inch penstock before
                i
                > > > size a turbine that sizes the penstock. Thanx
                > > >
                > >
                > > 1.
                > > This now the fifth time since October last year that I advise the
                > group that
                > > SF Pressure Drop 5.0 [available at http://www.pressure-drop.com/%5d
                > makes it easy
                > > to do any pipe friction/pressure drop calculation imaginable.
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