Air leakage flow in air pipeline

[orion1]

I want to calculate air leakage out of the pressuresed air pipeline through the hole . How can I calculate air flow as a function of pressure in the pipe and as the function of the diametar of the hole ? For example: we have hole diametar=6 mm and pressure= 6 bar? It is the ambient temperature t = 25 C.
Thank you.

 

[TD2K]

I would suggest you get a copy of Crane's technical flow of fluids. This is an example of choked compressible flow and is nicely dealth with.

The equation is:

W = 1891*do^2*Y*C*(dP*p)^0.5

do is the orifice diameter in inches

Y is the compressibility correction factor. For 6 bar air pressure going to atmospheric pressure through a 6 mm orifice, you can use 0.72.

C is the discharge coefficient for the opening, 0.6 is commonly used.

dP is the pressure drop in psi

p is the inlet gas density in lb/ft3.

 

[quark]

One more method is here.

http://www.cleandryair.com/system_leaks.htm

Ofcourse, no substitute to TD2K

Regards,

 

[orion1]

Thank you both for your answers. There is very usefull compressed air leak rate table on

http://www.cleandryair.com/LeakRateTable.htm

TD2K could you tell me, in the equation
W = 1891*do^2*Y*C*(dP*p)^0.5 , in what units is W?

Regards.

 

[patrickraj]

Units for W must be pounds/hr

 

[TD2K]

Patrikraj is correct, sorry for missing that term.

 

[patrickraj]

This can be solved as given in page 4-14 of CRANE TECHNICAL PAPER 10

I ASSUMED resistance coefficient K of 1.0(assuming pipe exit) & 25 DEG C temp and 6.0bar(g).

Critical flow takes place for this condition.
Mach no is 0.53915
Flow works out to 290.2lb/hr.

Hope this helps