Base-Condition Volumetric Flow Rate; Volume - Emerson Daniel 3410 Series Operation Manual

Section 4: Flow measurement
January 2018
4.5.7

Base-condition volumetric flow rate

The base-condition volumetric flow rate is the result converting the flow-condition volumetric
flow rate to the base pressure-temperature condition. This conversion requires (1) AGA8
calculations to be either performed internally (i.e., by the meter) or externally (with the
resulting compressibilities specified to the meter via the
and (2) the flow-condition temperature and pressure to be live or fixed. If AGA8 calculations are
not performed (i.e., neither internally nor externally) or the flow-condition temperature and/or
pressure are/is not enabled, then the base-condition volumetric flow rate is set to zero.The base-
condition volumetric flow rate is calculated as shown in
Equation 4-15 Base-condition volumetric flow rate
where
4.5.8

Volume

The Daniel 3410 Series Gas Ultrasonic Flow Meter meter provides forward and reverse volume
accumulators for each of the three volumetric flow rate values: raw, flow-condition (raw with
expansion and/or profile correction), and base-condition. Each volume accumulator is actually
stored as a data pair: (64-bit unsigned integer portion, 32-bit floating point fractional portion).
For example, a volume of 12345.750 m
0.750 m
(indicating forward flow) or negative (indicating reverse flow), the volume accumulators are
always positive values.
34
Q Q
=
Base Flow
=
Q
"raw" volumetric flow rate (m
Base
=
Q
flow-condition volumetric flow rate (m
Flow
= base-condition absolute pressure (MPaa) (PBase)
P
abs b ,
= flow-condition absolute pressure (MPaa) (AbsFlowPressure)
P
abs f ,
calculated as shown in
= base-condition temperature (K) (TBase)
T
b
= flow-condition temperature (K) (FlowTemperature)
T
f
= base-condition compressibility factor (ZBase)
Z
b
= flow-condition compressibility factor (ZFlow)
Z
f
3
as the fractional portion. Note that while a volumetric flow rate can be positive
3410 Series Gas Ultrasonic Meters Operations Manual
SpecZFlow
Equation
P  T  Z
   
abs f , b b
-------------- - ----- ----- -
     
P T Z
abs b , f f
3
/h) (QMeter)
3
/h) (QFlow)
Equation 4-10
3
is stored as 12345 m
3-9000-777 Rev E
and data points),
SpecZBase
4-15.
3
for the integer portion and
Base-condition volumetric flow rate