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Force of water flowing through a pipe?

  1. Apr 21, 2014 #1
    I was considering installing an immersion heater inside a vertical standpipe of a water tower (4-ft internal dia) in order to aid in freeze protection for winter. However, during full flow the tower drains at a flow rate of about 4,000 gal/sec! I want to make sure that there are sufficient drain cycles on the probe without there being a huge risk of it shearing... How can I easily/quickly determine how much force is being applied to the probe (mounted horizontally inside the pipe) while draining at full flow? The probe is steel, 28-in long, and 1-in in diameter.

    Any help would be great!

  2. jcsd
  3. Apr 21, 2014 #2


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    Figure out the velocity of the water flow during draining given the ID of the pipe and the flow rate.

    Estimate the total force on the probe using this velocity and a Cd of 1.0 for the cylinder in cross flow.

    When all is said and done, I estimate a total drag force of about 340 lbs. on your probe at full drainage flow, which it probably won't be able to withstand. I would investigate an alternate placement of the probe (perhaps aligned with the flow).
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