Gas flow rate calculation

[remp]

I am trying to do a calculation....

I have a gas line 10mm and approx 100m long. The pressure in the line is 7 bar when the outlet is closed and is maintained at 7 bar by the supply gas system (gas bottles) when the outlet is open.

How do I calculate the flow rate when the outlet is fully open at the end?

 

[BigInch]

You need to know 2 of 3 basic parameters for pipe flow work.
1) inlet pressure
2) outlet pressure
3) flowrate

From your description I think you're saying that the inlet pressure is maintained at 7 bar (but I don't know if its absoute pressure or gage pressure) and the outlet is maintained at atmospheric pressure. I'll assume pressures are in BarG and make that 7 and 0.

Now see the tutorial on gas flow equations,

http://www.psig.org/papers/2000/0112.pdf

And check your answer here,

http://www.lmnoeng.com/DarcyWeisbach.htm

Note the 40% pressure drop limitation.


**********************
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http://virtualpipeline.spaces.live.com/

 

[ione]

Remp,

What BigInch has stated is correct.

You may also use the Renouard equation:

pi^2 – po^2 = 46742*rho*L*Q^1.82*D^(-4.82)

where:
pi = pressure on the start of pipe line in bar
po = pressure on the end of pipe line in bar
rho = relative density
L = length in km
Q = flow rate in m3/h
D = pipe diameter in mm