Elster Instromet 2000 - Page 47

Model 2000 Flow Computer Instruction Manual
2.0 GENERAL DESCRIPTION
Model 2000 issue 21 Page No
40
Velocity of Sound in Flowing gas
4)
)10K()10K(
10P
C
3
t
6
6
2
t
6
5
t
5
0
g
ρ××+ρ××+
ρ
××γ
=
−−
Where
Cg : Velocity of Sound in Flowing gas Equation 4)
γ0 : Low Pressure Ratio of Specific Heats DATA ENTRY
pl : Line gas Pressure in Bar.a MEASURED
K5 : Constant DATA ENTRY
K6 : Constant DATA ENTRY
Velocity of Sound in Calibration Gas
5)
)10K()10K()K(KC
3
t
6
Cc4
2
t
3
Cc3tCc2Cc1c
ρ××+ρ××+ρ×+=
−−
Where
Cc : Velocity of Sound in Calibration gas Equation 5)
K1Cc : Constant DATA ENTRY
K2Cc : Constant DATA ENTRY
K3Cc : Constant DATA ENTRY
K4Cc : Constant DATA ENTRY
Alternative method of correcting for Velocity of Sound in Gas
6)
⎥
⎥
⎦
⎤
⎢
⎢
⎣
⎡
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
+
−×
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
+ρ
+ρ=ρ
15.273t
G
A
K
K
1
24t
3
ta
7)
0
b
d
G
γ
=
Where
ρa : Line Density of gas corrected for VOS and temperature in kg/m3 Equation 6)
G : Intermediate Equation Equation 7)
K3 : Constant DATA ENTRY
K4 : Constant DATA ENTRY
γ0 : Low Pressure Ratio of Specific Heats DATA ENTRY
A : Calibration Gas Constant (default 0.00281) DATA ENTRY
t2 : Downstream Line gas Temperature in °C MEASURED
db : Relative density of gas at base conditions MEASURED