Reynolds Number - Emerson Daniel 3410 Series Operation Manual

3410 Series Gas Ultrasonic Meters Operations Manual
3-9000-777 Rev E
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 Reynolds number
Re
where
PathFactor
Reynolds number
MAX PathFactor (
=
= Reynolds Number (dimensionless) (ReynoldsNumber)
Re
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
(dimensionless)
= geometric constant, pi (dimensionless) (3.14159...)
π
=
Q
"raw" volumetric flow rate (m
Raw
= natural gas mixture mass density at the flow condition (either
ρ
( P f T f )
,
calculated as part of internal AGA8 calculations or specified via
SpecRhoMixFlow) (kg/m3) (RhoMixFlow)
= pipe inside diameter (m) (PipeDiam)
D
in
= dynamic viscosity (Pa•s) (Viscosity)
μ
Equation 4-14.
Q ρ

Raw ( P f T f
,
 
4
)

-- - ------------------------------- -
 
π μ

D
TM
meters, 1.00 for SeniorSonic
3
/h) (QMeter)
Section 4: Flow measurement

)
4
,

10

TM
meters)
January 2018
33