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Flow-X─ Function Reference
Flow-X General functions - fxIAPWS_IF97_C
Function inputs
Remark
EU
Range
Default
Name
Optional tag name, tag description and
tag group
Temperature
°F
0 .. 4000
0
Pressure
psia
0..15000
0
Phase
The phase (water or steam) can be
calculated automatically or be set to
either steam or water.
1: Auto-select (calculate from t and p
inputs)
2: Steam
3: Water
If 'Steam' or 'Water' is selected, while the
combination of temperature and pressure
indicates the opposite phase, then the
function uses either the saturation
pressure (region 4) or the boundary
pressure (intersection regions 2 and 3)
instead of the input pressure for its
calculations.
1
Function outputs
Remark
EU
Fallback
Status
0: Normal
1: Input argument out of range
2: Calculation error
3: No convergence
Density
lbm/ft3
0
Enthalpy
Energy flow = Mass flow * Enthalpy
btu/lbm
0
Region
Actual IAPWS-IF97 region
0: Combination of t and p is outside the valid range
1: Water
2: Steam
3: Pressurized water
4: At the saturation line
5: High temperature steam (1472 ≤ T ≤ 3632 °F)
-
0
Saturation pressure
Saturation pressure at the input temperature.
Note: only calculated up to the critical temperature of
647.096 K (+- 705 °F), set to 0 for higher temperatures
psia
0
Dynamic viscosity
The dynamic viscosity is required for flow rate
calculations based on a differential pressure
measurement (e.g. orifice)
lbm/ft.s
0
Ratio of specific
heats
Equals the ratio of the specific heats cp / cv
cp : specific heat at constant pressure
cv : specific heat at constant volume
This ratio can be used as the isentropic exponent
value (also called 'kappa') when the real value is
unknown.
The isentropic exponent is required for flow rate
calculations based on a differential pressure
measurement (e.g. orifice)
-
0
Summary of Contents for flow-x
Page 1: ...Function Reference Certified flow calculations Flow and batch calculations Worksheet functions...
Page 331: ...Flow X Function Reference 5 331 Flow X IO Functions fxPT100Table...
Page 349: ...Flow X Function Reference 6 349 This page is intentionally left blank for user notes...
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