Hydraulic Head Loss (minor) loss coefficient References?

  • Thread starter Oleg Fomin
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  • #1

Main Question or Discussion Point

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. :)
 

Answers and Replies

  • #2
19,953
4,108
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. :)
Do you mean a tee?
 
  • #3
Do you mean a tee?
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
 

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  • #4
19,953
4,108
So it’s basically an elbow?
 
  • #5
So it’s basically an elbow?
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?
 
  • #6
19,953
4,108
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)?
 
  • #7
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)?
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
 
  • #8
jrmichler
Science Advisor
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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.
 
  • #9
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.
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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