Gas Chart Square Root Conversion Factors

Hi there,

The formula you need is as follows:

Q=K*sqrt(h/d)

Where

Q = Flow

K = Constant

h = differential head (delta pressure)

d = density

You will need to work out K which is a constant which includes the ratio of cross-sectional area of pipe to cross-sectional area of nozzle or other restriction, units of measurement, correction factors, and so on. This depends on the type of meter.

To get you into the ball park - you can assume k = 1

These formula apply to both gas and liquid and are used in calculating flow when you have an orrifice (flow element) and a DP cell.

Good luck and let us know how you fair?

Regards

Craig

Hi there,

Q = K*sqrt((P1-P2)/D)

Where

Q = flow

K = Constant

P1 - P2 = differential pressure

D = Density

K = (1.59923 * P * d^4 x p)/w^2

Where

P = change in pressure

d = pipe diameter

p = density

W = mass flowrate

As you have correctly stated K(the constant) is a ratio between the orrifice diameter and the pipe diameter.

I am not aware of a table that you can use, but by using the above formula you will be able to get the flowrate.

Regards,

Craig

More information is required if you want a more exact answer/Pipe ID, orifice plate type and size, temperature of gas,orifice expansion factor,etc. The formula for calculating approximate flow rate,using flange taps, and concentric orifice plate is: Q(SCFH)= 7727*Fa*Fpv*K*d Square*Y divided into the square root of h*Pf over G*Tf Where: Q=Gas Flow Rate at14.7 psi and 60F Fa= orifice expansion factor K=Flow coefficient(Cq*F) Y= gas expansion factor Pf= Pressure of flowing fluid G=Specific gravity of gas Tf=Temperature of flowing liquid Using a concentric orifice plate,with flange taps, on a 3" schedule 40 pipe,with a maximum orifice diameter of 1.448", and a gas specific gravity of 1, at 100 PSIG, and 60 Degrees F: at 200 inches of H2O it will flow approximately 1315 SCFM. at 100 inches, it will be about 930 SCFM. At 50 inches, it will be about 660 SCFM. At 20 inches, it will be around 420 SCFM.At 10 inches, it will be around 295 SCFM. This should get you in the ball park. ---------------------------------------------------------------------------------- HTRN

Here is a link to a calculator for flows of all type devices. http://www.controlengineering.se/flowcalc/flowcalceng.htm?gclid=CKae9-SgspcCFQrFGgodGiIeiw ________________________________________________________________________HTRN

Here is a link to a free calculator.: ---------------------------------------------------------------------------------http://www.efunda.com/formulae/fluids/calc_orifice_flowmeter.cfm --------------------------------------------------------------------------------- HTRN

Thanks to everyone for your replies. This definitely helps me out.

Mark