Hydraulic Head Loss (minor) loss coefficient References?

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Discussion Overview

The discussion revolves around the reference sources for minor head loss coefficients (k) in hydraulic engineering, specifically focusing on the challenges of finding values for a cross pipe fitting. Participants share their experiences and seek advice on reliable references for these coefficients.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant expresses difficulty in finding the minor head loss coefficient for a cross pipe fitting, noting that this information seems rare in textbooks.
  • Another participant questions whether the fitting in question is actually a tee, prompting clarification that it is a cross fitting with flow turning 90°.
  • There is a discussion about treating the cross fitting as an elbow in calculations, with concerns about the impact of additional branches on flow dynamics.
  • Participants consider whether to adapt results from a tee fitting for the cross fitting, and discuss the relative importance of accuracy for this fitting in the context of total network losses.
  • Standard references for minor head loss coefficients mentioned include Cameron Hydraulic Data and Crane TP-410, with one participant sharing their experience using these references in a previous job.
  • Concerns about the rising costs of reference materials are noted, with comparisons made to past prices of similar texts.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best approach to determine the minor head loss coefficient for the cross fitting, and multiple viewpoints on the relevance of different fittings and references remain present.

Contextual Notes

Participants express uncertainty regarding the applicability of existing references to the specific case of the cross fitting and the potential effects of its geometry on flow characteristics.

Oleg Fomin
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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. :)
 
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Oleg Fomin said:
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?
 
Chestermiller said:
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
 

Attachments

  • Cross fitting.jpg
    Cross fitting.jpg
    29.7 KB · Views: 616
So it’s basically an elbow?
 
Chestermiller said:
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?
 
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)?
 
Chestermiller said:
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
 
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.
 
jrmichler said:
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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