Two-Way Two-Position Valve
Two-position valve that controls flow between two ports
Description
Connections
Parameters
The Two-Way Two-Position Valve component allows flow between ports A and P with two positions to control the flow.
The real input s controls the position of the value. An input of 0 corresponds to position 0, an input of 1 to position 1. Intermediates values produce an averaged position, with the transition length set by the band parameter.
The following figure shows how s and band effect the valve opening.
Formulation Approaches
Two approaches were taken for formulation of the flow equation inside the device. When the boolean parameter Use constant Cd is true, a constant coefficient of discharge (Cd) is used, otherwise a variable coefficient of discharge with maximum value (Cd⁡max) and a critical flow number (Critno) are used.
Name
Modelica ID
portA
Hydraulic port to path A
portP
Hydraulic port for pump
s
Real input signal that controls valve position
General
Default
Units
Amax
1·10−4
m2
Maximum orifice opening area
Amin
1·10−12
Minimum orifice opening area (leakage)
band
0.1
Transition length in normalized spool displacement
Orifice
Use constant Cd
true
True (checked) means a constant coefficient of discharge is implemented, otherwise a variable Cd is used in flow calculation
UseConstantCd
Cd
0.7
Flow-discharge coefficient; used when Use constant Cd is true
ℜCr
12
Reynolds number at critical flow; used when Use constant Cd is true
ReCr
Cd⁡max
Maximum flow-discharge coefficient; used when Use constant Cd is false
Cd_max
Critno
1000
Critical flow number; used when Use constant Cd is false
Crit_no
Optional Volumes
Use volume A
false
True (checked) means a hydraulic volume chamber is added to portA
useVolumeA
VA
1·10−6
m3
Volume of chamber A
Va
Use volume P
True (checked) means a hydraulic volume chamber is added to portP
useVolumeP
VP
Volume of chamber P
Vb
For more information see Port Volumes.
See Also
Hydraulics Library
Valves
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