Liquid Controls SP4000 - Manual (Page 104)

101
SP4000 Flow Computer
Sensible Heat Flow:
Special Case for Water
heat flow = mass flow (Tf) • enthalpy ( Tf )
Liquid Delta Heat:
General Case
heat flow = mass flow • specific heat • ( T2 - Tf )
Water Case
heat flow = mass flow(Tf) • [enthalpy (T2 ) - enthalpy (Tf)]
Expansion Factor Computation for Square Law Flowmeters:
In the following Equations, delta P is assumed in ("H
2
O), Pf is in PSIA, 27.7 is a PSIA to ("H
2
O) units
conversion.
Liquid Case
Y = 1.0
Gas, Steam Case
Orifice Case
delta P
Y = 1.0 -(0.41 + 0.35•B 4 ) •
isentropic exponent • Pf • 27.7
V-Cone, Venturi, Flow Nozzle, Wedge Case:
NOTE: An equivalent formula is used by V-Cone flowmeter types.
Target, Annubar, Pitot Case:
7.3.9
Sensible Heat
Flow
Computation
7.3.10
Liquid Delta Heat
Computation
7.3.11
Expansion Factor
Computation for
Square Law Flow-
meters
∆
p
27.7 • p
f
R = 1 –
κ − 1
1 −β 4 ) • (
κ
• R
2/
κ
• (1 - R
(κ−1)/κ
)
[(1 −(β
•
4
R )) • (1 - R)]
2/
κ
Y =
= 1.0 Y
Heat Flow Computation:
Steam Heat
heat flow = mass flow • total heat steam(Tf, Pf)
Steam Net Heat
heat flow = mass flow • [total heat steam(Tf, Pf) - heat saturated water(Pf)]
Steam Delta Heat
heat flow = mass flow • [total heat saturated steam (Pf) - heat water (Tf)]
7.3.8
Heat Flow
Computation