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Reference, Installation, and Operations Manual Section 6: Meter operation
3-9000-743 Rev S June 2013
Volumetric flow rate 197
Equation 6-13 Flow-condition volumetric flow rate
where
Pressure-effect expansion correction
The meter is capable of correcting the raw volumetric flow rate for the effect of pipe expansion
due to pressure changes. Note that for the pressure-effect expansion correction factor to be
calculated, the correction must be enabled (via the EnableExpCorrPress data point) and the
flow-condition pressure must be available (i.e., the EnablePressureInput data point must be set
to ‘Live’(1) or ‘Fixed’(2), see Section 5.6.12). The pressure-effect calculation is shown in
Equation 6-14. If the pressure-effect expansion correction factor is not calculated, it is set to 1.0.
Equation 6-14 Pressure-effect expansion correction
where
=
flow-condition volumetric flow rate (m
3
/h) (QFlow)
=
“raw” volumetric flow rate (m
3
/h) (QMeter)
=
expansion correction factor due to pressure (dimensionless)
(ExpCorrPressure) calculated as shown in Equation 6-14
=
expansion correction factor due to temperature
(dimensionless) (ExpCorrTemperature) calculated as shown
in Equation 6-16
=
profile-effect correction factor (CorrectionFactor)
calculated as shown in Equation 6-17
=
expansion correction factor due to pressure (dimensionless)
(ExpCorrPressure)
=
pipe strain per unit stress (MPaa
-1
) (StrainPerUnitStress)
calculated as shown in Equation 6-15
=
flow-condition absolute pressure (MPaa)
(AbsFlowPressure) calculated as shown in Equation 6-23
=
reference absolute pressure (MPaa) (0.101325 MPaa)
Q
Flow
Q
Raw
()ExpCorr
P
()ExpCorr
T
()CorrFctr()=
Q
Flow
Q
Raw
ExpCorr
P
ExpCorr
T
CorrFctr
ExpCorr
P
13β× P
abs f,
P
ref
–()×[]+=
ExpCorr
P
β
P
abs f,
P
ref