KROHNE Summit 8800 Vol 2 - Manual (Page 181)

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08/2013 - MA SUMMIT 8800 Vol2 R02 en
SUMMIT 8800 APPENDIX 2: LIQUID CALCULATIONS 16
3) For both directions the volume flow rate is corrected as follows:
max 0
1
0
1 * *
re bodypressu atur bodytemper
line bc
Q
Q
Q
Q
q q 











=
Equation 12 Bi-directional volume flow rate
Where:
qbt Corrected volume flow [m3/hr]
qline Uncorrected volume flow [m3/hr]
16 .4 Low flow cut-off control
The low flow cut-off, entered in m³/h, determines whether the stream status is on-line or off-
line. As well as controlling the display status, this limit determines whether the stream can be
considered ‘non-flowing’ to enter or leave maintenance mode. The default value is around the
+/- 1%. Environment conditions may have an influence on this setting.
16 .5 Retrieve base density
The flow computer receives the base density from a keypad value of 1050kg/m3 at base condi-
tions.
16 .6 Temperature correction factor to base
The temperature correction factor to standard temperature is calculated by inserting the duty
stream temperature in:
) T - ( =
std
T T
∆
Equation 13 Delta temperature base correction
Followed by:
( ) [ ]
T 8 . 0 1 T exp C
b b tld
∆ α + ∆ α − =
Equation 14 Liquid temperature correction
Ctld Correction for liquid temperature at stream [-]
αb Oil thermal expansion coefficient at standard temperature [1/°C]
ΔT Temperature difference from standard temperature [°C]
For the first iteration, the line density is inserted for αb in the equation below. After this, the
value of αb from the previous iteration is used:
2
1
2
0 K
K K
b b
b
+ + =
ρ ρ
α
Equation 15 Liquid thermal expansion
αb Oil thermal expansion coefficient at standard temperature [1/C]
K0 API constant [-]