How to calculate expansion factor
Posted: Sun Mar 11, 2012 12:19 pm
I'm calculating the preliminary orifice size for orifice type flow meter of a natural gas flow. However, I only have the following info:
gas molecular weight: 24.18
gas mass flow rate: 11668 kg/h
gas density: 9.7 kg/m3
pressure upstream: 9.9 barg
Cp/Cv: 1.235
viscosity: 0.012 cP
pipe ID: 10.14 inch
temperature upstream: 65.9 deg C
Since I need to calculate the orifice size and pressure drop, I put an estimation of orifice size and trying to calculate the pressure drop from the equation based on the equation in ISO5167-2, qm = ACY (2 x density x dP / 1 - beta ration^4)^1/2. However, it requires me to compute the gas expansion factor from this equation, Y = 1-(0.41+0.35(beta ratio)^4)dP/(isentropic factor x pressure inlet)
Pls assist. Thank you.
gas molecular weight: 24.18
gas mass flow rate: 11668 kg/h
gas density: 9.7 kg/m3
pressure upstream: 9.9 barg
Cp/Cv: 1.235
viscosity: 0.012 cP
pipe ID: 10.14 inch
temperature upstream: 65.9 deg C
Since I need to calculate the orifice size and pressure drop, I put an estimation of orifice size and trying to calculate the pressure drop from the equation based on the equation in ISO5167-2, qm = ACY (2 x density x dP / 1 - beta ration^4)^1/2. However, it requires me to compute the gas expansion factor from this equation, Y = 1-(0.41+0.35(beta ratio)^4)dP/(isentropic factor x pressure inlet)
Pls assist. Thank you.