Compressible Flow of Air 1

[JKRNR]

I have 130m of 150mm nb pipe containing air at 4 barg. A
40 mm valve opens to de-pressurize the line to
atmospheric via a length of 40mm nb vent line. Can
anyone point to a calculation method or programme to give a plot of flowrate vs time.

 

[mbeychok]

JKRNR:

Read this online article:

www.air-dispersion.com/feature2.html

It contains two different methods (both of which produce the same answer) along with an example calculation of each method.

Hope this helps.

Milton Beychok
(Visit me at www.air-dispersion.com)
.

 

[sailoday28]

A calclation method is that of the "method of characteristics". Boundary conditions have to be known.
1. How fast does the valve open and what are its flow characteristics.
2. What is at the upstream or inlet to the valve? ie. dead ended? a reservoir as a source?
3. Initial temperature of the air?

See a text such as The Dynamics and Thermodynamics of Compressible Fluid Flow--Ascher Shapiro.

Regards