Flow-X─ Function Reference
4-189
Flow-X General functions - fxGERG2008_Gas
fxGERG2008_Gas
The compressibility, density, speed of sound and isentropic coefficient of a gas are calculated from its
composition, temperature and pressure in accordance with the GERG-2008 equation of state. The
function uses an optimized routine that only applies when fluid is in the gaseous state (100% gas) and
that requires limited CPU time (suitable for processing in the Flow-X flow computer).
Compliance
The GERG-2008 Wide-Range Equation of State for Natural Gases and Other Mixtures: An
Expansion of GERG-2004. Kunz, O., Wagner, W. Submitted to J. Chem. Eng. Data 57 (2012).
Boundaries
The GERG-2008 calculation has defined uncertainty bounds for fluids that lie within the 'Normal range'.
Also an 'Expanded range' of gas mixtures is defined for which the calculation has a higher uncertainty.
Using the calculation at conditions outside the 'Expanded range' is not recommended.
Input value
Normal Range
Expanded Range
EU
Pressure
0 .. 35
0 .. 70
MPa(a)
Temperature
90..450
60..700
K
Pressure
0 .. 350
0 .. 700
bar(a)
Temperature
-183 .. +177
-213 .. +426
°C
Pressure
0 .. 5076
0 .. 10153
psia
Temperature
-298 .. +350
-352 .. +800
°F
Mole fraction of all components
0.00 .. 1.00
0.00 .. 1.00
-
Function inputs and outputs
Function
inputs
Remark
EU
SW tag
Range
Default
Name
Optional tag name, tag
description and tag group
Pressure
Pressure value
bar(a)
0..2000
1.01325
Temperature
Temperature value
°C
-200..+400
0
Composition
Standard composition as
defined in section
'Standard gas composition.
mol/mol
COMP
0..1
0
neo-Pentane
mode
Determines what to do
when component neo-
Pentane is larger than zero
1: Add to i-Pentane
2: Add to n-Pentane
3: Neglect
-
NEOC5_MODE
1
Function
outputs
Remark
EU
SW tag
Alarm
Fallback
Status
0: Normal
1: Input argument out of range
2: Calculation error
3: No convergence
4: Mole fractions do not add up
to 1.0 +- 0.0001
6: Hardware not supported
STS
FIOOR
CALCERR
NOCONV
COMPERR
Compressibility
-
Z
1
Mass Density
kg/m3
MASDENS
0
Содержание flow-x
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