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NPSHA with Elevation raise

  1. Feb 27, 2017 #1
    Hello I have a system seen below that has two above ground raises in it.

    The minimum tank fluid height is 12 feet. Elevation of 75 feet.
    The first raise goes up 7 feet and the elevation is 66 feet.
    The second raise goes up 5 feet to 64 feet.
    The pump is a vertical can pump so the depth to its impeller is 10 feet.
    The fluid has a high vapor pressure of 12.8 psia and a friction loss of 3.2 feet.
    I attached my calculation, I know NPSHa is calculated by the eye of the impeller so I add the 10 feet... but how do I account for the elevation changes?
    Did I do it right?
    View attachment 113822

    NPSHA = Patm-Pvap + z1-z2 +pump depth - hf

    = (14.7-12.8 psia)×2.31/.72 + 75-66+10 -3.2

    NPSHa= 21.8feet
  2. jcsd
  3. Mar 4, 2017 #2
    Thanks for the thread! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post? The more details the better.
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