Basic water pressure formula

  1. ive scanned about 200 closely relevant posts to make sure im not one of those "here we go again" posts, but can find no basic water pressure formula. Specifically I need to calculate variable hypothetical water pressures (with a final conversion to GAUGE pressure) with a known INLET PSI, comparing pipe size, pipe configuration, change in elevation, etc. Short of a hundred bucks for an engineering book, i cant find this exact formula though a lot are close. I have my constants for friction loss, gravity, inlet psi, angled and reduced pipe fittings, but need the equation that ties all these together to constantly reference as i mix and match to achieve the highest psi possible, or at the least, economically feasible.

    thanks in advance to accurate replys
  2. jcsd
  3. stewartcs

    stewartcs 2,244
    Science Advisor

    Here are some formulas complements of Q_Goest a few posts below...


    Attached Files:

    Last edited: Feb 1, 2008
  4. Q_Goest

    Q_Goest 2,989
    Science Advisor
    Homework Helper
    Gold Member

    Hey, that looks familiar! lol
  5. FredGarvin

    FredGarvin 5,084
    Science Advisor

    I have a link to your post Q. It comes in handy quite often.
  6. To pumping crude oil (0.9 SG) with distance for 72 km on 8" steel pipe with flow rate as 725GPM and my question is how much the pressure (psi) to do this work ?

    Please help ?
  7. stewartcs

    stewartcs 2,244
    Science Advisor

    You need to provide more information. A sketch would be helpful. Make sure to note elevation changes, pipe schedule, etc...

    You can apply the general energy equation for fluid flow to find the required pressure once you determine the system layout.

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