C.3.1B Viscosity; Calculations For Gas ("Real Gas" And "Other Gas"); C.3.2A Density - GE PanaFlow MV80 User Manual

Appendix C. Flowmeter Calculations

C.3.1b Viscosity

The viscosity is based on an equation given by Keenan and Keys:
Where:
T is the temperature in Kelvin.
C.3.2 Calculations for Gas ("Real Gas" and "Other Gas")
Use this formula to determine the settings for "Real Gas" selections and "Other Gas" selections entered in the Fluid
Menu. The calculations for gas were taken from Richard W. Miller, Flow Measurement Engineering Handbook (Third
Edition, 1996).

C.3.2a Density

The density for real gases is calculated from the equation:
Where:
G = specific gravity
M
= molecular weight of air
w
p = flowing pressure
f
Z = flowing compressibility
R
= universal gas constant
o
T = flowing temperature
The specific gravity, and R
The hard coefficient to find is the compressibility, Z. Z is found using the Redlich-Kwong Equation (Miller page 2-18).
The Redlich-Kwong Equation uses the reduced temperature and pressure to calculate the compressibility factor. The
equations are non linear and an iterative solution is used. The Vortex program uses Newton's Method on the
Redlich-Kwong equations to iteratively find the compressibility factor. The critical temperature and pressure used in
the Redlich-Kwong equation are stored in the fluid data table with the other coefficients.
140
η poise (
are known and are stored in a table used by the Vortex meter.
o
5
–
⋅
1.501 10 T
)
------------------------------------ -
=
446.8 T ⁄
1
+
GM p
w Air , f
δ
------------------------- -
=
Z R T
f 0 f
PanaFlow™ MV80 & MV82 User's Manual