Nozzle/Branch pipe sizing
Nozzle/Branch pipe sizing
(OP)
Hi all, I'm quite new to piping engineering, and I've been tasked to determine the sizing/diameter of a branch pipe for a reducing tee junction.
Are there any equations that I can use to compute this?
I've seen some of the ASME B31.3/31.4 and I am not sure as how it is governed. for example, the use of the header-branch diameter ratio.
Thanks all in advance.
Are there any equations that I can use to compute this?
I've seen some of the ASME B31.3/31.4 and I am not sure as how it is governed. for example, the use of the header-branch diameter ratio.
Thanks all in advance.





RE: Nozzle/Branch pipe sizing
What would you be doing, if you knew that you could not fail?
RE: Nozzle/Branch pipe sizing
RE: Nozzle/Branch pipe sizing
Gas or liquid line?
Google the D'arcy or Darcy equation, or the Churchill equation to get the pressure drop in a pipe running full. Churchill is easiest, no iterations needed to determine friction factor.
What would you be doing, if you knew that you could not fail?
RE: Nozzle/Branch pipe sizing
They gave the an equation for flow of fluid through nozzle and orifices. There is a diameter term inside, so I'll just use it to compute?
RE: Nozzle/Branch pipe sizing
What would you be doing, if you knew that you could not fail?
RE: Nozzle/Branch pipe sizing
RE: Nozzle/Branch pipe sizing
What would you be doing, if you knew that you could not fail?
RE: Nozzle/Branch pipe sizing
RE: Nozzle/Branch pipe sizing
What would you be doing, if you knew that you could not fail?
RE: Nozzle/Branch pipe sizing
You could download the freeware from this site and model the branches with different flow rates and compare the losses.
http://ww
If you get to engineer systems of greater complexity you could invest in AFTs athom for steady state Impulse for dynamic analysis. The PSIM software is a cut down version of Fathom
"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.
http://waterhammer.hopout.com.au/
RE: Nozzle/Branch pipe sizing
In PSIM sotware the complex tee cannot be defined directly. However the pipes that are conencted to a tee can have a tee's losses defined.
Once drawn select the pipe and go to Fittings and Losses. Then select "Others" go to tees in the drop down menu. There you can add a tees loss, whether straight through or branch, to the pipe losses.
You could draw a system then copy and paste so two ssytems are on the workspace. One could be with losses and one without and you can see the differences.
Pipes could be kept short so losses in fittings mean more than straight pipe.
"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.
http://waterhammer.hopout.com.au/
RE: Nozzle/Branch pipe sizing
What would you be doing, if you knew that you could not fail?
RE: Nozzle/Branch pipe sizing
will do the manual calculations for this first and attempt the software in awhile!
thanks again guys.
RE: Nozzle/Branch pipe sizing
What would you be doing, if you knew that you could not fail?
RE: Nozzle/Branch pipe sizing
The AFT manual actually says all results should be checked by basic hand calculations. Sound advice indeed.
I you are member of a professional isntitution such as ASME, IMechE or Engineers Australia you will find that they have access to electronic libraries such as Knovel. there are numerous books on facilities piping that have the data you need to study.
The Crane reference is a classic as are books by Miller (Internal Flow Systems) and Idelchik.
http:
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http://boo
"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.
http://waterhammer.hopout.com.au/
RE: Nozzle/Branch pipe sizing
http://www.pumpfundamentals.com/pump_book.htm
"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.
http://waterhammer.hopout.com.au/
RE: Nozzle/Branch pipe sizing
RE: Nozzle/Branch pipe sizing
and also, for the division of flow for tee fitting, could i just use the ratio of areas to compute?
RE: Nozzle/Branch pipe sizing
1) the headloss equation for fittings, HL = K(v^2)/2g is for the head loss through the section of the branch pipe.
2) Division of flow for tee fitting, i'm supposed to use ratio of pressure drops. I've read that for reducing tee, flow split ratio may not be equal to ratio of areas.
RE: Nozzle/Branch pipe sizing
What would you be doing, if you knew that you could not fail?
RE: Nozzle/Branch pipe sizing
Also, your emphasis on knowing the flow rate for my design is that the velocity would be required, is that right?
RE: Nozzle/Branch pipe sizing
Three primary variables are,
Flow
Inlet pressure
Outlet pressure
knowing 2 of those, you can calculate the one missing variable.
Flow divided by pipe area = velocity
What would you be doing, if you knew that you could not fail?
RE: Nozzle/Branch pipe sizing
But now i'm stuck with a problem, how do I calculate pressure of a point in a flowing pipeline?
It has static and dynamic pressure components?
Say, for an underground buried pipe?
RE: Nozzle/Branch pipe sizing
Since two of the three variables I gave you above are pressure and you must know two of the three, at least one known variable must be a pressure.
If you know the upstream pressure, you can calculate downstream pressure, or visa versa. If you know both pressures, calculate the flow.
What would you be doing, if you knew that you could not fail?
RE: Nozzle/Branch pipe sizing
Thank you so much BigInch. I felt i have gained a lot from your comments. Thanks stanier as well.
RE: Nozzle/Branch pipe sizing
Come back when you have more questions.
What would you be doing, if you knew that you could not fail?
RE: Nozzle/Branch pipe sizing
BigInch, do you know of any pressure drop limits for large diameter pipelines? It seems like my pressure drop value is quite small though.
RE: Nozzle/Branch pipe sizing
What would you be doing, if you knew that you could not fail?
RE: Nozzle/Branch pipe sizing
Based on what I calculated, it seems the pressure loss over the length of branch pipe is around 0.07psi.
I'm not quite sure if such a small value of pressure loss would be practical as I have no dealt with such pressure loss calculations thus far.
Would your experience justify such a value for the above mentioned dimensions?
RE: Nozzle/Branch pipe sizing
If you have a 1.6 fps velocity the size is OK. The trick may be holding enough backpressure in the downstream connection to keep the branch pressure near the 229.93 something psi that you will need to keep your actually developed flowrate hanging around that calculated value. Without sufficient backpressure at the branch outlet in the downstream pipeline, flow in the branch will tend to accelerate. You need to verify that the downstream pipe pressure at that point is nearly 230 psig, or try to live with the increased flowrate, if it is lower, or for that matter, the decreased flowrate, or backflow, if it should be higher. If it's backflow, put in a check valve to stop backflow when the pressure is high. If the downstream pipe has a very low pressure, you will need to install a backpressure control valve on the branch to keep the flow from increasing.
What would you be doing, if you knew that you could not fail?
RE: Nozzle/Branch pipe sizing
7 ft diameter x 5 ft run, branch = 4 ft dia x 2 ft run?
That describes a single Tee fitting, not a pipeline. What are the lengths of the whole assembled run?
RE: Nozzle/Branch pipe sizing
(Qb/Qr) = [(Lr/Lb)*(Db/Dr)^5]^0.5
I apologize if I got that wrong and made myself look like a fool.