Volume Flowrate of Air in a Pipe

Hai, Names Rajah and I'm a Service and Project Engineer in a air compressor line. Your request on the question will be CFM, is it?

Yes U can Cosinder CFM or Cubic meter per sec

Actually i want volume flowrate of air in a pipe

Velocity of air x cross-sectional area of pipe = volumetric flow rate of air.

Impossible to say whether your equation for flow vs presure drop might be correct unless you give the units for all the quantities, and say whether flow/velocity is at actual conditions or (stated) standard conditiions.

But if you're talking about compressed air (7 barg/100 psig-ish) it's wrong, needs to include pressure and temperature of the flowing air.

If you mean ventilation air, where pressure is close to atmospheric, it could be correct.

Cheers.........Codey

As you know there is no flow without pressure drop. The force of the differential pressure motivates the air mass. Here is a formula from Norgren Helpful Engineering Information brochure. It is said to be based on the recognized Darcy formula.

Delta P = K Q^2 / 1000 x [14.7 / (14.7 + P psig)] x [(460 + t) /520]

Delta P = psi

Q= Flow in Standard Cubic Feet per Minute (SCFM)

t = Compressed air temperature, (Deg. F)

Values of K per 100 feet of straight, clean schedule 40 pipe size

1/8" = 2300

1/4" = 450

1/2" = 26.4

3/4" = 5.93

1" = 1.66

1 1/4" = .400

1 1/2" = .174

2" = .0467

2 1/2" = .0186

3" = .0060

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