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impeller performance from diameter

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  • mpthomas58
    Hi , a website that I looked at sometime ago and now I cannot remember its address had a handy formula guide/calculations which gave you a means to estimate
    Message 1 of 5 , Mar 5, 2011
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      Hi , a website that I looked at sometime ago and now I cannot remember its address had a handy formula guide/calculations which gave you a means to estimate the performance of an impeller if you had the diameters of the impeller .

      Your help would be most appreciated.
      regards
      Matthew
    • Jacques
      Hi Mathew, finally someone who can be bothered to put his name on an e-mail. I don`t think I have ever seen this site but I would be interested. The chart,
      Message 2 of 5 , Mar 6, 2011
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        Hi Mathew, finally someone who can be bothered to put his name on an e-mail. I don`t think I have ever seen this site but I would be interested. The chart, table or whatever would have to be based on speed and centrifugal pump type such as overhung impeller. However I am skeptical that the results would be reasonably accurate, however I would like to see it. I will keep an eye out.

        Jacques

        --- In pumpfundamentals@yahoogroups.com, "mpthomas58" <mpthomas58@...> wrote:
        >
        > Hi , a website that I looked at sometime ago and now I cannot remember its address had a handy formula guide/calculations which gave you a means to estimate the performance of an impeller if you had the diameters of the impeller .
        >
        > Your help would be most appreciated.
        > regards
        > Matthew
        >
      • Jacques
        Naturally, to establish a flow rate another very important factor is the width of the impeller. Jacques
        Message 3 of 5 , Mar 6, 2011
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          Naturally, to establish a flow rate another very important factor is the width of the impeller.

          Jacques
          --- In pumpfundamentals@yahoogroups.com, "mpthomas58" <mpthomas58@...> wrote:
          >
          > Hi , a website that I looked at sometime ago and now I cannot remember its address had a handy formula guide/calculations which gave you a means to estimate the performance of an impeller if you had the diameters of the impeller .
          >
          > Your help would be most appreciated.
          > regards
          > Matthew
          >
        • Jacques
          It is possible you could use this chart: http://www.pumpfundamentals.com/help5.html to predict pump performance. You would have to fix the specific speed which
          Message 4 of 5 , Mar 6, 2011
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            It is possible you could use this chart:

            http://www.pumpfundamentals.com/help5.html

            to predict pump performance. You would have to fix the specific speed which is not too difficult since the specific speed for standard volute type pumps is around 2000-3000. You would then have to guess at the efficiency, say 85%, you would then get the flow from the chart. You can then get the head using the specific speed value. It will not be very accurate because the efficiency influences the flow rate greatly on the chart.

            Jacques

            --- In pumpfundamentals@yahoogroups.com, "mpthomas58" <mpthomas58@...> wrote:
            >
            > Hi , a website that I looked at sometime ago and now I cannot remember its address had a handy formula guide/calculations which gave you a means to estimate the performance of an impeller if you had the diameters of the impeller .
            >
            > Your help would be most appreciated.
            > regards
            > Matthew
            >
          • S. L. Abhyankar
            Dear Mr. M. P. Thomas, For designing Pumps people follow different approaches. Every approach also recommends different empirical formulae and empirical values
            Message 5 of 5 , Mar 7, 2011
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              Dear Mr. M. P. Thomas,

              For designing Pumps people follow different approaches. Every approach also recommends different empirical formulae and empirical values of coefficients. Often times there are the values are in a range and there is no exactitude. That brings lack of exactitude to the design and in turn, variations in performance.

              Different approaches known to me are from books on pump-design by following authors. - (1) Pfleiderer (2) Stepanoff (3) Troskolansky and Lazarkiewitz (4) Nekrasov (5) Lobanoff (6) In Pump Handbook by Karassik, section 2 on Pump Design was contributed by Mr. Jekat (6) In India I have a book co-authored by Mr. Jagdish Lal, presenting metrication of original book by Mr. Austin Church (8) Area-Ratio theory of Anderson is again much different from the "Specific Speed"-approach of most of these authors.

              People have tried to theorise prediction of pump performance from shut-off (zero flow) to zero head. Mr Stepanoff gives analysis of even four-quadrant performance of a pump. But since design itself remains more an art than a science, prediction of performance will also be suspect of its exactitude.

              (9) Now CFD packages are also used to get velocity vector profiles of a design and to also apply inversion of the CFD analysis to improve or modify design and performance.

              In spite of all this surface finishes and replication of design profiles in pattern-making and casting do influence the actual performance. Making pumps in sheet-metal fabrication or by injection-moulding in non-metallic materials demand compromising with design profiles for retracting a press-work or moulding from a die.

              This is gist of my experience regarding design and performance prediction of centrifugal pumps.

              Thanks and regards,
              "Essel" (S. L. Abhyankar)

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