6 flow calculation, 6 flow, Calculation – Yokogawa digitalYEWFLO (DY) User Manual
Page 104
<11. MAINTENANCE>
11-6
IM 01F06A00-01EN
F1105.ai
Upstream
Number of bolts: 2
Number of bolts: 4
Number of bolts: 6
Upstream
Number of bolts: 10
Upstream
Upstream
g
h
f
c
d
c
d
c
d
e
f
e
c
d
e
f
g
h
i
j
k
l
Number of bolts: 8
Upstream
e
g
c
j
f
h
d
i
Figure 11.4 Procedure of tightening bolts
(e) Velocity (V)
V=N × 1
¨t
×
1
KT × U
KT
×
4
S×D
2
.... (11.7)
(f) Reynolds number (Re)
• Metric Units
Re=V × D ×
ρ
f
×
1
μ
× 1000
.... (11.8.1)
• English Units
Re=V × D ×
ρ
f
×
1
μ × 124
.... (11.8.2)
Where
N:
Number of input pulses (pulse)
t: Time corresponding to N (seconds)
f
:
Instrumental error correction factor
e
:
Expansion correction factor for
compressive fl uid
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 fl ow unit time
(ex./m (minute) is 60.)
P
R
:
Pulse rate (ex. E+ 3 is 10
3
.)
T
f
:
Temperature at operating conditions (°C)
(°F)
F
S
: Flowrate
span
T
R
: Total
rate
D:
Internal diameter (m) (inch)
μ :
Viscosity (mPa • s(cP))
f
:
Density at operating conditions (kg/m
3
)
(lb/ft
3
)
11.6 Flow Calculation
(1) Flow Calculation
The fl owrate is calculated with the following
equations based on the N number of generated
vortices:
(a) Flow rate (in engineering units) (RATE)
RATE=N ×
1
¨t
×
ε
f
×
ε
e
×
ε
r
×
1
KT U
k
U
TM
....(11.1)
• Metric Units
KT=KM × U
KT
Ч {1–4.81 Ч (T
f
–15) × 10
–5
}
....
(11.2.1)
• English Units
KT=KM Ч {1–2.627 Ч (T
f
–59)×10
–5
} ....
(11.2.2)
(b) Flow rate (%) (RATE (%))
RATE(%)=RATE
×
1
F
S
× 100
.... (11.3)
(c) Totalized value (TOTAL)
TOTAL=TOTAL
+
∆TOTAL ....
(11.4)
1
T
R
¨TOTAL=RATE
×
¨t
Ч
Ч
1
U
TM
.... (11.5)
(d) Pulse output frequency (PULSE FREQ)
• Scaled pulse
PULSE FREQ=RATE ×
1
P
R
×
1
U
TM
.... (11.6.1)
• Unscaled pulse
PULSE FREQ= N × 1
¨t
1
P
R
.... (11.6.2)