YOKOGAWA AE100D, Инструкция по эксплуатации

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IM 1F6A0-01E 8-8
8. TROUBLESHOOTING
(3) Mass Flow calculation
a) Steam
In case of saturated steam, mass flow rate is calculated
from density values to temperature measured by using
saturated steam table.
In case of superheat steam, mass flow rate is calculated
from density values to temperature measured by using
steam table. In order to measure superheat steam, it is
necessary to make canstant pressure value. A pressure
values which is enterd in parameter is used.
M =
ρ
ft
• Q
f
..........................................................................................................
(8.14.1)
b) Gas
In case of gas, Volumetric flow rate at standard
condition is calculated, so Pressure-Temperature
correction is carried out. It is necessary to make
canstant pressure value. A Pressure values at operational
condition, temperature and pressure value at standard
condition which is enterd in parameter is used.
Q
n
= Q
f
• –– • –––––––––– • –– ........................... (8.14.2)
c) Liquid
In case of liquid, mass flow late is calcurated from
which used to calculate the secondary function for the
density value to the temperature. A density value which
indicated by the order sheet is used.
M =
ρ
n
• Q
f
• {1 + a
1
(T
ft
– T
n
) + a
2
(T
ft
– T
n
) 2 } .... (8.14.3)
Where
M : Mass flow
Q
n
: Volumetric flow rate in a Standard condition
Q
f
: Volumetric flow rate in a operating condition
ρ
ft
: Density calculated by temperature value
ρ
n
: Density in a Standard condition (kg/m 3 ), (lb/cf)
P
f
: Pressure in an operating condition (kPa abs), (psi)
P
n
: Pressure in a standard condition (kpa abs), (psi)
T
n
: Temperature in an operating condition (
°
C), (
°
F)
T
f
: Temperature in a standard condition (
°
C), (
°
F)
T
ft
: Measured temperature value (
°
C), (
°
F)
a
1
: 1st temperature coefficient
a
2
: 2nd temperature coefficient
P
f
T
n
+ 273.15 1
P
n
T
fT
+ 273.15 K