3410 Series Gas Ultrasonic Meters Operations Manual Section 4: Flow measurement
3-9000-777 Rev E January 2018
3410 Series gas flow meter characterizations 37
The non-volatile mass total data points are as listed in the table below:
4.6 3410 Series gas flow meter characterizations
For Daniel 3410 Series Gas Ultrasonic Flow Meter SeniorSonic meters only, the following flow
characterizations are calculated/estimated: symmetry, cross-flow, chord turbulence, profile
factor, and swirl angle. Alarm limits are provided for the chord turbulence and swirl angle values.
Symmetry
Symmetry is a dimensionless measure of the flow symmetry comparing the upper chords to the
lower chords and is readable via the
Symmetry data point. Ideally the Symmetry should be 1.0.
Cross-flow
Cross-flow is a dimensionless measure of the flow symmetry comparing the chords on one side
of the meter to the chords on the other side. It is readable via the
CrossFlow data point. Ideally
the Cross-flow should be 1.0.
Chord turbulence
Chord Turbulence is a estimate of the turbulence (percentage) at a chord location. A value is
calculated for each active chord and is readable via the
TurbulenceA, TurbulenceB, TurbulenceC,
or
TurbulenceD data points. A value of 0% indicates no appreciable turbulence.
Profile Factor
The profile factor is a dimensionless ratio of the inner chord velocities to the outer chord
velocities. It is readable via the
ProfileFactor data point. Ideally the Profile Factor should be 1.0
for Dual-X meters (model 3422) and 1.17 for British Gas-style meters (model 3400).
Swirl angle
The swirl angle is an estimate of the swirl (to the nearest degree) and is readable via the
SwirlAngle data point. It is calculated as a function of the meter body style and Profile Factor
(see above). A value of 0 degrees indicates no appreciable swirl.
Table 4-5 Mass total data points
Forward direction Reverse direction
Integer Fraction Integer Fraction
PosMass PosMassFrac NegMass NegMassFrac
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