Flowrate of Compressible air flow in a pipe
Flowrate of Compressible air flow in a pipe
(OP)
Hi all,
I have to calculate the fluwrate in a 3 m, 3/8" pipe (with some flanges etc.). the driving force of flow is pressure difference: 75,3 kPa on one side of the pipe and 44,1 kPa on the other side. it seems like a very straightforward problem but I couldn't find something useful in 3 fluid mechanics & gas dynamics books. do you know the equation for this?
Thanx in advance
I have to calculate the fluwrate in a 3 m, 3/8" pipe (with some flanges etc.). the driving force of flow is pressure difference: 75,3 kPa on one side of the pipe and 44,1 kPa on the other side. it seems like a very straightforward problem but I couldn't find something useful in 3 fluid mechanics & gas dynamics books. do you know the equation for this?
Thanx in advance





RE: Flowrate of Compressible air flow in a pipe
http://www.psig.org/papers/2000/0112.pdf
thread798-114881: Flow rate of N2 with know pressure
RE: Flowrate of Compressible air flow in a pipe
Check out eFunda at http://www.efunda.com where one can find free online calculators and background technical information.
Thanks,
G. Feric, PE
http://engware.i-dentity.com
RE: Flowrate of Compressible air flow in a pipe
Good luck,
Latexman
RE: Flowrate of Compressible air flow in a pipe
my pressures are 75,3 kPa and 44,1 kPa absoulte. (Cabin pressure and ambient pressure @ 40000 ft.). So the flow is compressible.
RE: Flowrate of Compressible air flow in a pipe
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Flowrate of Compressible air flow in a pipe
Good luck,
Latexman
RE: Flowrate of Compressible air flow in a pipe
Good luck,
Latexman
RE: Flowrate of Compressible air flow in a pipe
Geoffrey D Stone FIMechE C.Eng;FIEAust CP Eng
www.waterhammer.bigblog.com.au
RE: Flowrate of Compressible air flow in a pipe
The pipe has 7 90 degrees bends and 3 45 degrees bends. it has 21 welded joints. (as a result of strict installation envelope).
I am trying to simulate the environment in flowmaster now. hope our results match.
Thanks in advance.
RE: Flowrate of Compressible air flow in a pipe
Good luck,
Latexman
RE: Flowrate of Compressible air flow in a pipe
Good luck,
Latexman
RE: Flowrate of Compressible air flow in a pipe
I finished the simulation. calculated flowrate is 0,01259lbm/sec. What was your result?
RE: Flowrate of Compressible air flow in a pipe
Guessing an air temperature on 20 deg C I calculated the diameter that would give you the flow you calculated. I get an ID of 0.45", so I would guess you are very close to the right answer.
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Flowrate of Compressible air flow in a pipe
K = 1 + 7*14*0.0277 + 3*8*0.0277 + 0.5 = 4.88
gamma = 1.4
viscosity = 0.0159 cP
for 0.545" ID w = 0.0105 lb/sec
for 0.493" ID w = 0.0151 lb/sec
for 0.423" ID w = 0.0191 lb/sec
Good luck,
Latexman
RE: Flowrate of Compressible air flow in a pipe
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Flowrate of Compressible air flow in a pipe
25 degrees C
K = 1 + 7*14*0.0277 + 3*8*0.0277 + 0.5 = 4.88
gamma = 1.4
viscosity = 0.0159 cP
for 0.545" ID w = 0.0191 lb/sec
for 0.493" ID w = 0.0151 lb/sec
for 0.423" ID w = 0.0105 lb/sec
Thanks katmar!
Good luck,
Latexman