Technical data

Reynolds Number Equation 3-14:
Re =
(
4
π
)
Q
R
aw
ρ
(
ρ
f
T
f
)
D
in
μ
Re=
Reynolds Number (dimensionless) (ReynoldsNumber)
π =
geometric constant, pi (dimensionless) (3.14159...)
Q
Raw
=
“raw” volumetric flow rate (m
3
/h) (QMeter)
P(P
ƒ
T
ƒ
) =
fluid mass density at the flow condition (specified via SpecRhoMixFlow) (kg/m
3
)
(RhoMixFlow)
D
in
=
pipe inside diameter (m) (PipeDiam)
µ =
dynamic viscosity (Pa•s) (Viscosity)
3.5.6 Volume forward and reverse accumulators
Flow rate forward and reverse volume accumulators
The Daniel 3810 Series Liquid Ultrasonic Flow Meter provides forward and reverse volume
accumulators for both of the two volumetric flow rate values: raw and flow-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
3
is stored as
12345 m
3
for the integer portion and 0.750 m
3
as the fractional portion. Note that while a
volumetric flow rate can be positive (indicating forward flow) or negative (indicating
reverse flow), the volume accumulators are always positive values. The non-volatile
volume accumulator data points are listed in Table 3-3 below.
Non-volatile volume accumulator data pointsTable 3-3:
Volumetric Flow Rate
Type Forward flow direction Reverse flow direction
Integer Fraction Integer Fraction
Raw PosVolUncorr PosVolUncorrFrac NegVolUn-
corr
NegVolUncorrFrac
Flow-condition PosVolFlow PosVolFlowFrac NegVolFlow NegVolFlowFrac
3.6 3810 Series liquid flow meter diagnostics
3.6.1 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.
This is only applicable to 3814, 4-path meter types.
Flow measurement
24 Daniel 3810 Series Operations Manual