Pressure Loss in Tee 2

[metheral]

Hello, I'm looking for pressure loss information for a tee with a smaller branch size.

It's a 3" Tee with a 1/2" branch. Most of the flow carries on through the tee while a portion goes through the 1/2" branch. Is there a K value or equivalent length or pressure drop calculation that can be done for this scenario?

 

[PEDARRIN2]

I would probably approximate it by using the pressure drop of a standard Tee through the branch and add the pressure drop from a 3" pipe to a 1/2" pipe.

It won't be exact - but should be close.

 

[metheral]

Would that give you the pressure drop in the 1/2" branch or in the 3" main line?

 

[Latexman]

1/2" branch.

Good luck,
Latexman

 

[metheral]

It's actually the main 3" flow pressure drop that i'm trying to figure out...

 

[JohnGP]

If it was an equal tee with 3" x 1/2" reducer, then I would use the "run" value for a tee. If it's a 3" reducing tee, then I would probably just consider it as a length of pipe equal to the tee length.

Cheers,
John

 

[metheral]

Thanks, I appreciate your comments!

 

[metheral]

Oh, and FYI, this would be a reducing tee. It's for a 3" header that has nozzles coming out of it.

 

[mauricestoker]

This might be useful.

http://www.bechtel.com/assets/files...01 Estimating the Pressure Drop of Fluids.pdf

 

[JohnGP]

mauricestoker,

The referenced paper doesn't cover the situation that the OP was querying, but a star nonetheless - I'm sure it will be a useful reference for me at some stage.

Cheers,
John

 

[metheral]

I agree with JohnGP in that this paper looks useful, but it looks like the values it provides are for the pressure drop in the small branch line, not the main line.

 

[katmar]

@metheral - you mention pipes coming out of a header. This makes it more of a diverging manifold problem than a reducing tee problem. As the liquid flows along the header its velocity reduces because some fluid has exited via the branches. As the velocity decreases, the pressure can actually increase - thanks to Bernoulli. As JohnGP mentioned you could use the K value for the "run" of a standard tee to estimate the pressure loss. This would be about 0.06. Offset against this is the pressure recovery due to deceleration. The balance between these two effects is discussed in Perry (and many other articles on manifold design).

@mauricestoker and JohnGP - thanks for the link Maurice. To me the most important conclusion that can be made from this article is that for normal piping design work the trusted old method of "a standard tee plus an entrance loss" leads to negligible errors. The error is probably less than the uncertainty in the pipe fabrication tolerances and welding quality.

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