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FLOWSIC600 · Technical Information · 8010125 V 4.0 · © SICK AG
Product Description
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2.3.2
Calculating the volumetric flow rate
The uncorrected volumetric flow rate Q
v*
is calculated from the flow velocity v
A
and the
open cross-sectional area in the meter body‘s measuring section:
This intermediate result is still dependent on Reynolds number and the properties of the
flow profile (asymmetry, swirl). It is corrected using the following formula:
Profile factor
Fixed gas pressure: mean pressure in the operating range, register #7041
"Pressure(Fixed)".
The sets of factors CC
0
to CC
4
and K
0
to K
5
are nominal size-dependent constants which
were determined by the manufacturer and which are related to a particular FLOWSIC600.
Correcting the impact of pressure and temperature on the geometry of the meter body
The geometry parameters of the meter body are based on ambient temperature of 20
°
C
and 1 bar(a) and have been optimized to minimize deviations due to the influence of
pressure and temperature. However, there is still an impact of pressure and temperature
on the geometry of the meter body and thus on the measured value. This impact is
corrected as follows:
D:
Internal diameter
of the meter body,
Reg. #7100
"InnerDiameter"
D
²
·
Qv
*
= v
A
·
4
Also
Q
v, corr
= Q
v
·
(1 + K
T
·
(T – 293.15) + K
p
·
p)
The temperature coefficient K
T
is material-specific and is 4.12 · 10
-5
K
-1
for carbon steel
and 5.23 · 10
-5
K
-1
for stainless steel.
The pressure coefficient K
p
was determined to be 6 · 10
-6
bar
-1
.
Q
v
= Q
v*
·
(1 +
f
[Q
v*
, p
abs
, CC
0...4
, PF, K
0...5
])
v
avg1
+
v
avg4
PF =
v
avg2
+
v
avg3
p
p
min
p
max
1bar
+
=
Reg. #7040
"Temperature(fixed)"
Reg. #7041
"Pressure(Fixed)"
Reg. #7118
"ExpCorrTemperature
Reg. #7117
"ExpCorrPressure"