Emerson Daniel 3410 Series Operation Manual page 33

Operations manual
DAN-20057316
4.5.2 Flow-condition volumetric flow rate
The flow-condition volumetric flow rate is the result of applying expansion correction and
flow- profile correction to the raw volumetric flow rate as shown in
volumetric flow rate
flow cut-off value, it is set to zero. The low-flow cut-off volumetric flow rate (CutRate) is
the specified low-flow velocity threshold (ZeroCut) converted to a volumetric flow rate.
where
Q
Q
ExpCorr
(ExpCorrPressure) calculated as shown in
ExpCorr
(ExpCorrTemperature) calculated as shown in
4.5.3 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
pressure-effect calculation is shown in
correction factor is not calculated, it is set to 1.0.
Equation 4-9: Pressure-effect expansion correction
ExpCorr
(ExpCorrPressure)
ß = pipe linear expansion coefficient due to temperature (MPaas-1)
(StrainPerUnitStress) calculated as shown in
P
abs,f
shown in
P
ref
the pipe linear expansion coefficient (K)
Equation 4-10: Pressure-effect strain per unit stress
β = pipe strain per unit stress (MPaa-1) (StrainPerUnitStress)
Model 3418 GUSM
subject to the low- flow cut-off. If the resulting value is below the low-
Q
Flow
= flow-condition volumetric flow rate (m
Flow
= "raw" volumetric flow rate (m
Raw
= expansion correction factor due to pressure (dimensionless)
P
= expansion correction factor due to temperature (dimensionless)
T
Configure the pressure parameters for the
ExpCorr
= expansion correction factor due to pressure (dimensionless)
P
= flow-condition absolute pressure (MPaa) (AbsFlowPressure) calculated as
Equation 4-12
= reference absolute pressure (MPaa) (0.101325MPaa) reference temperature for
= Q ExpCorr
Raw P
3
/h) (QFlow)
3
/h) (QMeter)
Equation
Equation
Equation 4-9. If the pressure-effect expansion
= 1 + 3 × β × P
P abs, f
Equation
D 1+υ + D
2 2
β =
out in
E × D ‐D
2 2
out in
Measurement
Flow-condition
ExCorr
T
4-9.
4-11.
meter. The
− P
ref
4-8.
1‐2υ
January 2019
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