IM 1F6A0-01E
8-7
8. TROUBLESHOOTING
8.4 Software Configuration
(1) Flow Calculation
The flowrate is calculated with the following equations based
on the N number of generated vortices:
(a) Flowrate (in engineering units)
RATE=N.
1
䉭
t
.
ε
f
.
ε
e
.
ε
r
.
1
KT
. U
KT
. U
k
. U
TM
.
1
S
E
.... (8.1.1)
KT=KM . {1–4.81
×
(Tf–15)
×
10
–5
}
.... (Metric Units)
.... (8.1.2)
KT=KM . {1–2.627
×
(Tf–59)
×
10
–5
}
.... (English Units)
.... (8.1.3)
(b) Flowrate (%)
RATE(%)=RATE .
1
F
S
.... (8.2)
(c) Totalized value
TOTAL=N .
ε
f
.
ε
e
.
ε
r
.
1
KT
. U
KT
. U
k
.
1
T
E
.... (8.3.1)
TOTAL=Ef .
ε
e
.
ε
r
. N
.... (Unscaled pulses)
.... (8.3.2)
(d) Velocity
V=N .
1
䉭
t
.
1
KT
. U
KT
.
4
π
D
2
.... (8.4.1)
(e) Reynolds number
Red=V . D .
ρ
f
.
1
µ
×
1000
.... (Metric Units)
.... (8.5.1)
Red=V . D .
ρ
f
.
1
µ
×
124
.... (English Units)
.... (8.5.2)
where N:
Number of input pulses (pulse)
∆
t:
Time corresponding to N (seconds)
ε
f
:
Instrumental error correction factor
ε
e
:
Expansion correction factor for compressive
fluid
ε
r
:
Reynolds number correction factor
KT:
K-factor at operating conditions (pulses/
litre) (pulse/gal)
KM:
K-factor at temperature 15
°
C (59
°
F)
U
KT
:
Unit conversion factor for K-factor
U
k
:
Flow unit conversion factor (Refer to item
(2))
U
k
(user): Flow unit conversion factor for user’s unit
U
TM
:
Factor corresponding to flow unit time (ex./
m (minute) is 60.)
S
E
:
Span factor (ex. E+ 3 is 10
3
.)
P
E
:
Pulse rate (ex. E+ 3 is 10
3
.)
T
f
:
Temperature at operating conditions (
°
C)
(
°
F)
F
S
:
Flowrate span
T
E
:
Total factor
D:
Internal diameter (m) (inch)
µ
:
Viscosity (cP)
ρ
f
:
Density at operating conditions (kg/m
3
) (
艎
b/
ft
3
)
(2) Flow Conversion Factor (Uk)
Flow conversion factor Uk is obtained by carrying out the
following computation depending on the selection of the fluid
to be measured and the flow unit.
(a) Steam
M (Mass flowrate): U
k
=U
ρ
f
. U
k
(kg)
.... (8.6.1)
U
k
=
ρ
f
. U
k
(
艎
b)
.... (8.6.2)
Qf (Flowrate at operation): U
k
=U
k
(m
3
)
.... (8.7.1)
U
k
=U
k
(acf)
.... (8.7.2)
(b) Gas
Qn: (Flowrate at STP):
U
k
= U
k (Nm
3
)
P
f
P
n
P
f
+ 273.15
P
n
+ 273.15
1
K
·
·
·
.... (8.8.1)
U
k
= U
k (scf)
P
f
P
n
1
K
(T
n
-32)
+ 273.15
(T
n
-32)
+ 273.15
9
5
9
5
·
·
·
M: (Mass flowrate): U
k
=
ρ
f
. U
ρ
f
. U
k
(kg)
.... (8.9.1)
U
k
=
ρ
f
. U
ρ
f
. U
k
(
艎
b)
.... (8.9.2)
Qf: (Flowrate): U
k
=U
k
(m
3
)
.... (8.10.1)
U
k
=U
k
(acf)
.... (8.10.2)
(c) Liquid
Qf: (Flowrate): U
k
=U
k
(m
3
)
.... (8.11.1)
U
k
=U
k
(acf)
.... (8.11.2)
M (Mass flowrate): U
k
=
ρ
f
. U (kg)
.... (8.12.1)
U
k
=7.481
×ρ
f
. U (
艎
b)
.... (8.12.2)
7.481 is a conversion factor of U.S
gal into acf
(d) User’s unit
U
k
=U
k
(user)
.... (8.13)
where
M: Mass flow
Q
n
: Volumetric flow in a Normal condition
M: Mass flow
Q
f
: Volumetric flow in an operating condition
ρ
f
: Specific weight (kg/m
3
), (
艎
b/acf)
h
f
:
Specific enthalpy (kcal/kg), (Btu/
艎
b)
T
f
: Temperature in an operating condition (
°
C), (
°
F)
T
n
: Temperature in a Normal condition (
°
C), (
°
F)
P
f
: Pressure in an operating condition (kg/cm
2
abs), (psia)
P
n
: Pressure in a Normal condition (kg/cm
2
abs), (psia)
K: Deviation factor
ρ
n
: Density in a Normal condition (kg/Nm
3
), (
艎
b/scf)
ρ
f
: Density in an operating condition (kg/m
3
), (
艎
b/acf)
U
k(kg)
, U
k(cal)
, U
k(Nm3)
, U
k(m3)
U
k(lb)
, U
k(Btu)
, U
k(scf)
, U
k(acf)
: Unit conversion factors
