Emerson Daniel 3414 - Reynolds Number

3410 Series Gas Ultrasonic Meters Operations Manual Section 4: Flow measurement
3-9000-777 Rev E January 2018
Reynolds number 33
4.5.6 Reynolds number
Reynolds Number is a dimensionless value that represents the nature of the gas flow within the
pipe. Although the primary reason for calculating Reynolds Number is for two path and bounce
path meters (device numbers 3412 and 3411) profile-effect correction, the value is calculated
for all meter types.
Reynolds Number is calculated as shown in Equation 4-14.
Equation 4-14 Reynolds number
where
= Reynolds Number (dimensionless) (ReynoldsNumber)
MAX
= maximum function that takes the maximum of the values within
the brackets
= factor to (approximately) correct for velocity profile effects (0.94 for
JuniorSonic
TM
meters, 1.00 for SeniorSonic
TM
meters)
(dimensionless)
= geometric constant, pi (dimensionless) (3.14159...)
=
“raw” volumetric flow rate (m
3
/h) (QMeter)
= natural gas mixture mass density at the flow condition (either
calculated as part of internal AGA8 calculations or specified via
SpecRhoMixFlow) (kg/m3) (RhoMixFlow)
= pipe inside diameter (m) (PipeDiam)
= dynamic viscosity (Pa•s) (Viscosity)
Re MAX PathFactor()
4
π
---


Q
Raw
ρ
P
f
T
f
,()
μ
D
--------------------------------



10
4
,=
Re
PathFactor
π
Q
Raw
ρ
P
f
T
f
,()
D
in
μ