KEP ES749 - ILVA Flow Meter Equations

ES749 Flow Computer
100
ILVA Flowmeter - This meter type requires an initial linearization using the lineariza-
tion table. In addition, the following specialized corrections are required.
For Gas/Steam Expansion (imperial) Y = 1 – (115.814 • (dp / p) • 0.0001)
Where: Y = gas expansion correction (NOTE: Y=1 for liquid)
dp = differential pressure - inches water gauge
p = upstream pressure - psia
For Reynolds Number (volumetric calculations for Gas/Steam)
Cre = (1 – (n / Qn)
-1
to a maximum value of m
Where: Cre = Reynolds number correction (NOTE Cre = 1 for liquid)
Qn = nominal water volumetric owrate (column 6)
m = (see table below)
n = (see table below)
Meter Size
n m
DN50 2.53 1.200
DN80 0.64 1.125
DN100 0.21 1.100
DN150 0.13 1.067
DN200 0.07 1.050
DN250 0 1
DN300 0 1
The nal gas expansion and Reynolds number correction is: Qc = Qn • Y • Cre
For Volumetric Calculations: (calculate the density corrected volumetric owrate):
Qd = Qc • (Dn / Da)
0.5
Where: Qd = density corrected volumetric owrate
Qc = nominal water volumetric owrate (column 6) corrected for
Reynolds Number and gas expansion effects.
Da = actual owing density of working uid
Dn = nominal density of water at reference conditions
Once corrected for density a further correction is required to take into account the
effect of temperature on the ILVA primary element.
Temperature Compensation
For Volumetric Calculations: Using the value of Qd derived above, the temperature
corrected owrate can be calculated: Qa = ((Ta - Tref) • 0.000189 • Qd) + Qd)
Where: Qa = actual volumetric owrate
Qd = density corrected volumetric owrate (from above)
Tref = reference temperature in °C (generally 20°C)
Ta = actual owing temperature of working uid (in °C)
It is possible to convert from a mass owrate to a volumetric owrate and vice versa
using the following simple formula: Ma = Qn • Da
Where: Da = actual owing density of working uid
7.3.13
ILVA Flow Meter
Equations