Control Valve Calc
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CONTROL VALVE USER GUIDE Controlvalve Regulation valve sizing Version Creation date Correspondant Last revision This calculation sheet is the property of the …... and shall not be disclosed to others or reproduced in any manner without its permission. Databook has to be read and assimilated before using the worksheet. It is advised to make the first calculation by hand in order to have a better comprehension of the method a 1 REFERENCE This note is in accordance with the international standard for sizing control valves 2 ASSUMPTIONS Calculation consider valves without adjacent fittings They are made for turbulent flowrates 3 DOMAIN OF VALIDITY NA 4 FORMULAS 4.1.Symbols Cv = valve sizing coefficient q = Volumetric flowrate(m3/h) W = Mass flowrate (kg/h) P1 = Upstream absolute static pressure P2 = downstream absolute static pressure Pv = Absolute vapor pressure of liquid at inlet temperature. Pc = Absolute thermodynamic critical pressure Gf = liquid specific gravity (ratio of density of liquid on density of water) T1= Absolute upstream temperature °K Z = Compressibility factor M = gas molecular weight d1=Downstream density of blend, kg/m3 d2=Downstream density of blend, kg/m3 W1l=upstream liquid flow, kg/h W2l=downstream liquid flow, kg/h W1v=upstream vapor flow, kg/h W2v=downstream vapor flow, kg/h d1l=upstream liquid density, kg/m3 d2l=Downstream liquid density, kg/m3 d1v=upstream vapor density, kg/m3 d2v=Downstream vapor density, kg/m3 5 OBJECTIVE This worksheet permits to calculate : - The Cv of the valve for liquid, vapor or two phase flows. Cv is the sizing coefficient used to characterize the flow capacity of valves. It corresponds to the number valve in one minute when the valve differential pressure is 1 PSI. - The flowrate circulating across the valve for a given Cv will be calculated with a manual approach 6 INPUT Input have to be filled into yellow boxes xT and Cf coefficients depend on the kind of valve. Their values for the main types of valves are r Default values are atribuate to coefficients gamma, xT and Cf if the corresponding cells are kept em Curves describing the Cv % evolution in function of the shutting valve is available in the guard "ope This evolution can be simulated with parabolic (P), linear (L), equal % (%) ou quick opening (QO) cur 7 RESULTS Results are displayed into blue boxes and these cells are protected. All formulas are available in the sheet " Formulas_comparison". Formulas enclosed in blue are used in the Cf = Factor of critical flow given by the constructor ( is equivalent to the FL coefficient: pressur xT = rated pressure drop ratio factor FF = factor resulting from the liquid critical pressure Fg= factor corresponding to the specific heat ratio gf = mass fraction of the liquid phase gg= mass fraction of the vapor phase
description
Dimensionamento de Válvulas de Controlo
Transcript of Control Valve Calc
CONTROL VALVE Calculation note
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CONTROL VALVE
USER GUIDE
Controlvalve Regulation valve sizingVersionCreation dateCorrespondantLast revision
This calculation sheet is the property of the …... and shall not be disclosed to others or reproduced in any manner without its permission.
Databook has to be read and assimilated before using the worksheet.It is advised to make the first calculation by hand in order to have a better comprehension of the method applied.
1 REFERENCEThis note is in accordance with the international standard for sizing control valves
2 ASSUMPTIONS
Calculation consider valves without adjacent fittingsThey are made for turbulent flowrates
3 DOMAIN OF VALIDITYNA
4 FORMULAS4.1.SymbolsCv = valve sizing coefficientq = Volumetric flowrate(m3/h)W = Mass flowrate (kg/h)P1 = Upstream absolute static pressureP2 = downstream absolute static pressurePv = Absolute vapor pressure of liquid at inlet temperature. Pc = Absolute thermodynamic critical pressure
Gf = liquid specific gravity (ratio of density of liquid on density of water)
T1= Absolute upstream temperature °KZ = Compressibility factorM = gas molecular weight
d1=Downstream density of blend, kg/m3 d2=Downstream density of blend, kg/m3W1l=upstream liquid flow, kg/h W2l=downstream liquid flow, kg/hW1v=upstream vapor flow, kg/h W2v=downstream vapor flow, kg/hd1l=upstream liquid density, kg/m3 d2l=Downstream liquid density, kg/m3d1v=upstream vapor density, kg/m3 d2v=Downstream vapor density, kg/m3
5 OBJECTIVEThis worksheet permits to calculate :- The Cv of the valve for liquid, vapor or two phase flows.
Cv is the sizing coefficient used to characterize the flow capacity of valves. It corresponds to the number of US gallons flowing though the valve in one minute when the valve differential pressure is 1 PSI.
- The flowrate circulating across the valve for a given Cv will be calculated with a manual approach of the specific flowrate.
6 INPUTInput have to be filled into yellow boxes
xT and Cf coefficients depend on the kind of valve. Their values for the main types of valves are recorded in the sheet "table".Default values are atribuate to coefficients gamma, xT and Cf if the corresponding cells are kept empty (Cf cells comments)
Curves describing the Cv % evolution in function of the shutting valve is available in the guard "opening"This evolution can be simulated with parabolic (P), linear (L), equal % (%) ou quick opening (QO) curves
7 RESULTS Results are displayed into blue boxes and these cells are protected.
All formulas are available in the sheet " Formulas_comparison". Formulas enclosed in blue are used in the sheet "design"
Cf = Factor of critical flow given by the constructor ( is equivalent to the FL coefficient: pressure recovery factor)
xT = rated pressure drop ratio factor
FF = factor resulting from the liquid critical pressureFg= factor corresponding to the specific heat ratiogf = mass fraction of the liquid phasegg= mass fraction of the vapor phase
CONTROL VALVE Calculation note
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CONTROL VALVE FORMULAS
DATABOOK FORMULATIONS MASONEILAN FORMULATIONS FISCHER FORMULATION (ANSI/ ISA/IEC)
non critical flow
critical flow WITH
Compressible fluids
non engorged
is limited to 0.667
Engorged
Two phase flow
Avec vaporisation de liquide WITH
Avec
limited to
limited to
Sans vaporisation de liquide
NOTE1) In the calculation sheet:
2)3) Fitting attached to valve can have a significant impact for high recovery valves ( example: rotary valves like butterfly or ball valves) which
4) Fr= facteur du nombre de Reynolds Si Rev<56; Fr=0.019 (Rev)^0.67Si Rev>40000; Fr=1Si 56<Re<40000; cf coubes de Fisher (p2-7)
5) Formulation enclosed in blue are used in the sheet "design"
Liquid Service
non critical
critical
DP est limité à 0.5 * Cf ² *P1
DP est limité à 0.5 * Cf ² *P1
It is considered a valve installed without adjacent fitting and so FP =1It is considered a turbulent flow and so FR =1
If it is considered fitting attached to the valve, xT should be replaced by xTP which combine xT and piping geometry factor
have a rather low pressure drop coefficient at full opening. Manufactrers often provide FP values for swages installed adjacent to such rotary valves.
C V= w27.3∗C f∗F P∗F R∗√ΔPs∗γ 1
ΔP<C f ²*(ΔP s)
ΔP≥C f ²*(ΔP s )
x<Fγ∗x T
x≥Fγ∗x T
C V= W94 .8∗F P∗P1∗0 .667
∗√ T 1∗ZFγ∗x T∗M
Fγ=γ1 .4x=
ΔPP1
C V= W27.3
∗√ f fΔp f∗γf
+ f gΔP g∗γ g∗Y ²
P 1−P2<12∗C f ²*P 1
C V= q295
∗√ G∗T∗Z(P 1−P 2 )(P 1+P 2 )
P 1−P2≥12∗C f ²*P 1
C V=q
257∗C f∗P 1∗√G∗T∗Z
ΔP f=P1−P2
ΔP g=P1−P2
ΔP f=C f ²*(P1−F F∗P v)
ΔP g=F γ∗x T∗P 1
C V=51 .8∗W√ΔP∗(d1+d2 )
C V=36.6∗W√ΔP∗d1
d 1= W∗10 3̂W 1 ld1 l
+W 1vd1v
d 2= W∗10 3̂W 2ld2 l
+W 2 vd2v
C V= W94 .8∗F P∗P1∗Y
∗√T 1∗Zx∗M
Y=1−x
3∗Fγ∗x T
C V= w27.3∗F P∗F R∗√ΔP∗γ 1
ΔP s=P1−(0 .96−0.28∗√ P vP c )∗P v
Y=1−x
3∗Fγ∗x T
Fγ=γ1 .4
Y=1−ΔPG
3∗Fγ∗x T∗P1
CONTROL VALVES calculation note
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CONTROL VALVE
Activity-unit: N°
DateRevisionIssued by
Checked byItem old old old old old old
ServiceCase DESIGN DESIGN DESIGN DESIGN DESIGN DESIGN
PR
ES
SU
RE Inlet Pressure bar (g)
Pressure Drop bar 0.0 0.0 0.0 0.0 0.0 0.0
Outlet pressure bar (g)
FLO
W
Temperature °C
Vap. FlowRate kg/hr
Liq. FlowRate kg/hr
Total FlowRate kg/hr
Over margin %
Flow Rate kg/hr
VA
PO
UR
Vapour Fraction (weigth)
Molecular Weigth
Viscosity cP #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!
Compressibility
Cp/Cv (= gamma)
Density @(0 ATM,15.66°C) kg/m3 #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!
Density @ cond. kg/m3 #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!
LIQ
UID
Density
Viscosity cP
Critical Pressure bar a
Vapour Pressure bar a
Fluid (liq +vap) Density kg/m3
VA
LVE (Cf table)
Flow regime
Calculated Cv (If two phase flow : Cv= Cv gas + Cv liq )
Installed Cv
Opening Law (QO / % / L / P )
Openning %
Margin @ 80% opening % (g)
OP
EN
ING Quick Opening
Equal Percentage
Linear
Parabolic
Quick Opening
Equal Percentage
Linear
Parabolic
In the case of 2 phase flow with incondensable liquid and incondensable gas or with a liquid mixing to its own vapor, Cv value is calculated hereafter:
Cv
NOTES:
kg/m3
XT (coefficient of rate from the diferential pressure of a regulation valve with no adjacent link , at engorged flow): Cf Table
Cf
FLO
W
CH
AR
AC
-T
ER
IST
IC
MA
X F
LO
W
@ 8
0%
O
PE
NIN
G
NEW DATANEW DATA
NEW DATANEW DATA
NEW DATANEW DATA
NEW DATANEW DATA
NEW DATANEW DATA
NEW DATANEW DATA
F25
If the cell is kept empty, g =0.9 is considered by default.
G25
If the cell is kept empty, g =0.9 is considered by default.
H25
If the cell is kept empty, g =0.9 is considered by default.
I25
If the cell is kept empty, g =0.9 is considered by default.
J25
If the cell is kept empty, g =0.9 is considered by default.
K25
If the cell is kept empty, g =0.9 is considered by default.
F33
If the cell is kept empty, XT=0.7 is considered by default.
G33
If the cell is kept empty, XT=0.7 is considered by default.
H33
If the cell is kept empty, XT=0.7 is considered by default.
I33
If the cell is kept empty, XT=0.7 is considered by default.
J33
If the cell is kept empty, XT=0.7 is considered by default.
K33
If the cell is kept empty, XT=0.7 is considered by default.
F34
If the cell is kept empty, Cf =0.9 is considered by default
G34
If the cell is kept empty, Cf =0.9 is considered by default
H34
If the cell is kept empty, Cf =0.9 is considered by default
I34
If the cell is kept empty, Cf =0.9 is considered by default
J34
If the cell is kept empty, Cf =0.9 is considered by default
K34
If the cell is kept empty, Cf =0.9 is considered by default
B50
CAREFUL! This formula is only correct for 2 phase flow with incondensable liquid and incondensable gas or with a liquid mixing to its own vapor
CONTROL VALVE Calculation note
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CONTROL VALVE
0 10 20 30 40 50 60 70 80 90 100
0
10
20
30
40
50
60
70
80
90
100
% Cv
% o
pen
ing
Equal percentage
Modified parabolic
Quick opening
CONTROL VALVE Calculation note
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CONTROL VALVE
Opening law definition in function of the % Cv
%Opening Linearization%Cv Q op Eq % MP L Q op Eq % P
0 0 0 0 0.0 0.0 0.05 3.2 21.5 15 5 3.1 20.1 14.410 5.9 37 24.5 10 5.9 38.6 25.120 11 55.5 39 20 11.0 57.1 38.830 16 67 47.5 47.5 30 16.0 67.9 47.940 21.5 75.3 55 40 21.4 75.6 55.350 27 81 63 50 26.9 81.5 62.860 32 86 70 60 32.3 86.4 70.270 38 90.5 77.5 70 38.0 90.5 77.780 47 85 80 46.3 94.0 85.190 61.5 92 90 63.1 97.2 92.695 79.5 95 78.1 98.6 96.3100 100 100 100 100 100.4 100.0 100.0
% Cv @ 80% opening Q op Eq % P79.999 79.999 79.999 95.5 47.25 73.12
CONTROL VALVE Calculation note
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CONTROL VALVE
Typical values of valve coefficientValve type Trim Type Flow direction
Globe, single port
3 V-port plug Open or Close 0.9 0.7 0.48
4 V-port plug Open or Close 0.9 0.7 0.41
6 V-port plug Open or Close 0.9 0.7 0.3
Contoured plugOpen 0.9 0.72 0.46
Close 0.8 0.55 1
60 diameter hole drilled cage Outward or Inward 0.9 0.68 0.13
120 equal diameter hole drilled cage Outward or Inward 0.9 0.68 0.09
Characterized cage, 4 portOutward 0.9 0.75 0.41
Inward 0.85 0.7 0.41
Globe, double portPorted Plug Inlet between seats 0.9 0.75 0.28
Contoured plug Either direction 0.85 0.7 0.32
Globe, angle
Contoured plugOpen 0.9 0.72 0.46
Close 0.8 0.65 1
Characterized cage, 4 port Outward 0.9 0.65 0.41
VenturiInward 0.85 0.6 0.41
Close 0.5 0.2 1
Globe, small flow trim
V-notch Open 0.98 0.84 0.7
Flat seat Close 0.85 0.7 0.3
Tapered needle Open 0.95 0.84
Rotary
Eccentric spherical plugOpen 0.85 0.6 0.42
Close 0.68 0.4 0.42
Eccentric conical plugOpen 0.77 0.54 0.44
Close 0.79 0.55 0.44
Butterfly (centered shaft)
Swing-through (70 °) Either 0.62 0.35 0.57
Swing-through (60 °) Either 0.7 0.42 0.5
Fluted vane (70 °) Either 0.67 0.38 0.3
High performance butterfly (eccentric shaft) Offset seat (70 °) Either 0.67 0.35 0.57
BallFull bore (70 °) Either 0.74 0.42 0.99
Segmented ball Either 0.6 0.3 0.98
CF or FL XT Fd
WORKSHEET HISTORICS
Version Number Creation date Author Evolution details
V1.0 4/2/1999 G.Viguié Control_valve_r0
V1.0 3/10/2004 L. Van de Velde Control valve-Modification of the esthetic shape-Formulas updating-New table making the comparison between the formulas from the databook, fisher and Masoneilan constructors.
V1.1 9/7/2004 L. Van de Velde Control valve-Correction of the flow regime calculation
V1.2 11/11/2004 L. Van de Velde Control valve- User guide development- Updating of the sheets "Table" and "Formulas_comparison"
"Controlvalve_V1.2" has been validated by Daniel Martinière on march 2005V1.21 9/21/2005 L. Van de Velde Control valve
- Form revision in order to be in accordance with TECHNIP Standard
V1.22 12/15/2005 L. Van de Velde Control valve- Correction of a bug concerning the Y calculation in case of compressible fluids for a non engorged case.
