Jason
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There are several methods the one I use is developed by M.W. Kellogg.
Eff% =80-0.2855H+3.78x10-4HF-2.23x10-7HF2+5.39x10-4H2-6.39x10-7H2F+4.0x10-10H2F2
H = Developed head
ft F = Flow in GPM (gallons per minute) Applicable for heads from 50 to 300 ft and flows from 100 to 1000 GPM
8 months ago
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Joe D
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Mikey, You've asked a very general question inloving many factors and variables. ie; the type of pump reciprocating or centrifugal?
open or closed vain? the type of media being moved or pumped air,gas,liquid,slurry ect,...?
Factors such as impeller diameter, Wearing ring clearance's, discharge and backplate clearance's as well as surface finishes ie; PL/POL/Passivation are also factors to be considered as well as H.P., RPM, ect,... this site does have factors for the Affinity/Similarity Equations as in past years I have seen them. I'm not sure if it will provide NPSH or Envelope graphs though.
Probably the best method for rating any pumps efficiency is most likely through Performance Testing with a test tank.
Please if you can be a little more specific about your requirements for this question so we can help you.
7 months ago
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valdesroberto
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n pump = Mechanical energy increase of the fluid / Mechanical energy input = ((delta)Emech,fluid/Wshaft,in) = Wpump,u/Wpump
8 months ago
Source: Thermodyncamics an Engineeing Approach 5th ed.
Cencel & Boles
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vcastro66
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If you're just looking to estimate it, and not to solve for exact numbers, the best way is to assume a standard efficiency. For water pumps, you can get between 85-90% efficiency. it depends on how accurate you need to be. Otherwise, using the other two equations stated is your best bet.
8 months ago
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ultimate
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The volume of media pumped in hour is the best way to estimate the efficiency of a pump. The more media pumped, more efficient the pump; because pump is meant for it.
7 months ago
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