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Hydraulic Head Loss (minor) loss coefficient References?

  1. Jul 13, 2018 #1
    Hi all,
    Quick question:

    What do you guys use as your reference for minor head loss coefficients (k).

    I'm sure those with more experience have their own database/excels of k values found over the years. I have been personally using a combination of my Hydraulic Engineering Textbook and Google. However I have recently come across something which stumped me. I cannot seem to find the loss coefficient for a cross pipe fitting anywhere (I looked at three different textbooks).

    I can understand why this is such a rare tidbit of information, as I've personally haven't seen a cross fitting in actual use until now, but still... someone somewhere must have run a head loss test. :)
     
  2. jcsd
  3. Jul 13, 2018 #2
    Do you mean a tee?
     
  4. Jul 13, 2018 #3
    No, It is an actual cross fitting (not sure of a better term for it) with the flow turning 90°

    I'm attaching the picture of what I'm talking about, the flow is outlined in yellow, and the other two branches are stopped with valves.
    Cross fitting.jpg
     
  5. Jul 13, 2018 #4
    So it’s basically an elbow?
     
  6. Jul 13, 2018 #5
    At the moment, that's how I'm treating it in my calculations, but the actual fitting has four 8" pipes entering it at right angles, so I wasn't sure, if that would affect flow more so than just a rounded elbow.

    Surely there will be more turbulence/vorticity around the other two unused openings, but perhaps their effect is negligible.
    This leads me to a related question, what will have a bigger impact: flow direction change or the internal geometry of the fitting?
     
  7. Jul 13, 2018 #6
    Maybe adapt the result for a tee, since the flow in each half of the tee looks something like what you have? At least compare the equivalent results for a tee and an elbow. How accurate does this thing have to be (since it’s probably only a small part of the total network)?
     
  8. Jul 13, 2018 #7
    You're right, the loss for this particular fitting is not as important to the total losses, especially so because the flow tends to slow down by this point.
    I guess I was just looking for confirmation from other people that this is indeed something rare, and not something I was misreading or overlooking and also if there were perhaps a more reliable reference for these values than textbooks (something more along the lines of Steel/concrete manuals for structural design, but for hydraulics).

    Thank you for your help.
    ~Oleg
     
  9. Jul 13, 2018 #8
    Standard references are Cameron Hydraulic Data and Crane TP-410 - Flow of Fluids Through Valves, Fittings, and Pipe. My copy of Cameron got a lot of use back when I worked in a paper mill.

    The current price of Crane 410 is insane. The price was $8.00 when I bought my copy in 1985.
     
  10. Jul 13, 2018 #9
    Thank you,
    I'll check for those in the library where I'm currently interning at.

    Just looked up the Crane 410 ... I see what you mean.
    I guess it's a common trend today, pretty much any reference book is expensive, I paid around 150-200 for my copy of the Steel Manual, my instructor remembers buying it for somewhere around ~$20-30 (if not less).
     
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