Valve Port with Land (IL-PB)
R2026bLibraries:
Simscape /
Fluids /
Isothermal Liquid /
Valves & Orifices /
Hydromechanical Valves
Description
The Valve Port with Land (IL-PB) represents a valve port and spool land that meters flow. The metering area on side B or F increases as the land moves in the positive or negative direction relative to the valve port, which creates a flow path between port Af and port B or F, respectively.
Use the Flow momentum force model (side B) or Flow momentum force model (side F) parameter to specify the method the block uses for calculating the flow momentum force. The block always models the pressure force. The block calculates the pressure force from the gauge pressure at port B or F, depending on the active flow path, multiplied by the land area. A positive fluid force pushes the land in the positive direction, and a negative fluid force pushes the land in the negative direction.
Port Relations
Ports F and B are hydromechanical valve
composite ports that have valve_body, spool,
and fluid nodes, where:
The position of
B.valve_bodyis equal to the position ofF.valve_body.The position of
F.spoolrelative toB.spoolis the value of the Land width along valve axis parameter.
The opening distance is either the position of B.spool relative
to the valve port edge on side of port B or the position of
F.spool relative to the valve port edge on side of port
F. If Metering edge geometry is
Sharp Edge, the flow path is closed at an opening
distance of 0. If Metering edge geometry is
Chamfer, the flow path is fully closed when the
opening distance is equal to the negative of the value of the Chamfer
setback parameter.
The land can move to meter the port from side B or F. These figure shows the port relations for both metering directions.
Metering Area
The metering area depends on the metering edge and valve port geometry and which side is metering the flow.
When Metering edge geometry for the metering side is
Sharp Edge and Valve port
geometry is Regular slot, the metering
area and maximum metering area are
where:
x is the distance between the port edge and the land piston face.
lp is the value of the Port length along valve circumference parameter.
wp is the value of the Port width along valve axis parameter.
When Valve port geometry is Round
holes, the metering area and maximum metering area are
where:
np is the value of the Number of holes along valve circumference parameter.
dp is the value of the Hole diameter parameter.
When Metering edge geometry for the metering side is
Chamfer and Valve port
geometry is Regular slot, the metering
area and maximum metering area are
where:
wc is the value of the Chamfer setback along valve axis parameter.
θc is the value of the Chamfer angle with respect to valve axis parameter.
When Valve port geometry is Round
holes, the metering area and maximum metering area are
where:
When Metering edge geometry for the metering side is
Tabulated metering area, the block uses a lookup
table to determine the metering area from the Opening distance
vector and Metering area vector
parameters.
Jet Angle Calculations and Flow Effects
When Flow momentum force model for the metering side is
None, the block does not include the flow momentum
force. However, it does model the pressure force.
When Flow momentum force model for the metering side is
Based on von Mises jet angle, the jet angle is
where:
αcracking is the value of the Cracking jet angle for valve port inflow or Cracking jet angle for valve port outflow parameter, depending on the direction of the flow at port Af.
αmetering is the value of the Metering jet angle for valve port inflow or Metering jet angle for valve port outflow parameter, depending on the direction of the flow at port Af.
is the distance between the port edge and the land piston face, except when Metering edge geometry is
Chamfer. In that case, = x+wc.
When the opening moves beyond the fully open or fully closed positions, the block smoothly transitions the jet angle to 90° over a distance of 0.1 multiplied by the value of either the Port width along valve axis or Hole diameter parameter. Because of the jet angle saturation, the flow momentum force smoothly transitions to zero when the land edge moves away from the valve port.
The block does not modify the jet angle calculation for metering edge geometry modifications such as chamfers because the geometry and fluid jet interaction is too complex to approximate with a lumped parameter model. If your system uses machined geometry modifications to the land edge to mitigate the flow momentum force, estimate the jet angle empirically by either fitting the von Mises jet angle parameterization or using the tabulated parameterization.
When Flow momentum force model for the metering side is
Based on tabulated jet angle, the block calculates
the jet angle by using a lookup table from the Opening distance vector for
jet angle parameter and either the Jet angle vector for
valve port inflow or Jet angle vector for valve port
outflow parameter, depending on the direction of the flow at port
Af.
When the land is metering the flow from the F side, the flow momentum force is
When the land is metering the flow from the B side, the flow momentum force is
Mass Flow Rate
The mass flow rate through the fluid flow path is
where:
Δp is the pressure differential.
Δpcrit is the critical pressure differential.
ρavg is the average fluid density.
Ar is the ratio from the metering area to the connecting area.
Cd is the value of the Discharge coefficient parameter.
A is the metering area.
The critical pressure differential is
where:
Rec is the value of the Critical Reynolds number parameter.
ν is the fluid kinematic viscosity.
Block Sub-Components
The Valve Port with Land (IL-PB) block is equivalent to a composite component that comprises these blocks:
The equivalent diagram is:

Variables
To set the priority and initial target values for the block variables prior to simulation, use the Initial Targets section in the block dialog box or Property Inspector. For more information, see Set Priority and Initial Target for Block Variables.
Nominal values provide a way to specify the expected magnitude of a variable in a model. Using system scaling based on nominal values increases the simulation robustness. Nominal values can come from different sources, one of which is the Nominal Values section in the block dialog box or Property Inspector. For more information, see Modify Nominal Values for a Block Variable.
Examples
Ports
Conserving
Parameters
References
[1] Manring, Noah D. Hydraulic Control Systems. John Wiley & Sons, 2005.
[2] Merritt, Herbert E. Hydraulic Control Systems. John Wiley & Sons, 1967.
[3] von Mises, R., 1917. Berechnung von Ausfluß und uberfallzahlen. VDI, (22), pp. 469-474.
Extended Capabilities
Version History
Introduced in R2026b

