Reference, Installation, and Operations Manual

Section 6: Meter operation

3-9000-743 Rev S

June 2013

 

 

 

Equation 6-13 Flow-condition volumetric flow rate

QFlow = (QRaw)(ExpCorrP)(ExpCorrT)(CorrFctr)

where

 

 

QFlow

=

flow-condition volumetric flow rate (m3/h) (QFlow)

QRaw

=

“raw” volumetric flow rate (m3/h) (QMeter)

ExpCorrP

=

expansion correction factor due to pressure (dimensionless)

 

=

(ExpCorrPressure) calculated as shown in Equation 6-14

ExpCorrT

expansion correction factor due to temperature

 

 

(dimensionless) (ExpCorrTemperature) calculated as shown

 

=

in Equation 6-16

CorrFctr

profile-effect correction factor (CorrectionFactor)

 

 

calculated as shown in Equation 6-17

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

ExpCorrP = 1 + [3 ⋅ β ⋅ (Pabs, f Pref)]

where

 

 

ExpCorrP

=

expansion correction factor due to pressure (dimensionless)

 

=

(ExpCorrPressure)

β

pipe strain per unit stress (MPaa-1) (StrainPerUnitStress)

Pabs, f

=

calculated as shown in Equation 6-15

flow-condition absolute pressure (MPaa)

 

=

(AbsFlowPressure) calculated as shown in Equation 6-23

Pref

reference absolute pressure (MPaa) (0.101325 MPaa)

Volumetric flow rate

197