Panametrics PanaFlow MV80, Руководство пользователя, Страница: 174 / 184

Appendix C. Flow Meter Calculations
162 PanaFlow™ MV80, MV82 & MV84 User’s Manual
C.4.2b Viscosity
The viscosity for real gases is calculated using the exponential equation for two known viscosities. The equation is:

cP
aT
K
n
=
Where:

a
and
n
are found from two known viscosities at two temperatures:
n
In

cP
 
2

cP
 
1
  
In T
K2
T
K1
  
-----------------------------------------------
=
and
a

cP
 
1
T
K1
n
-------------------
=
C.4.3 Calculations for Liquid
Use this formula to determine the settings for “Goyal-Dorais” selections and “Other Liquid” selections entered in the
Fluid Menu. The liquid calculations were taken from Richard W. Miller, Flow Measurement Engineering Handbook
(Third Edition, 1996).
C.4.3a Density
The liquid density is found using the Goyal-Doraiswamy Equation. Goyal-Doraiswamy uses the critical
compressibility, critical pressure and critical temperature, along with the molecular weight to find the density. The
equation for specific gravity is:
G
F
p
c
Mw
T
c
--------------
0.008
Z
c
0.773
-------------- 0.01102
T
f
T
C
-----
–
 
 
 
=
The specific gravity can then be converted into density.