Pressure-Compensated Flow Control Valve (IL)

Pressure-controlled flow control in an isothermal liquid system

pressure compensated flow control valve (il)

Description

The Pressure-Compensated Flow Control Valve (IL) unit provides constant pressure flow control through the Orifice (IL) and Pressure Compensator Valve (IL) units connected in series. When the control pressure over the orifice reaches or exceeds the Set orifice pressure differential, the pressure reducing valve in the pressure compensator component begins to close, which maintains orifice pressure.

For systems that divert or redirect fluid to another part of the system, see block Pressure-Compensated 3-Way Flow Control Valve (IL).

The opening and closing of the valve is controlled by a physical signal to the S port. A positive signal opens the valve. Flow Control Valve Diagram:

pressure compensated flow control valve (il) 1

Numerically smoothed area and pressure

If the orifice parameterization is linear, the computational robustness of the simulation at the extremes of the range of orifice area and valve pressure is maintained by the Smoothing factor parameter, whose value must be greater than 0 and less than 1. If the Smoothing factor parameter is non-zero, the block applies the smoothing function to all calculated areas and pressures, but it primarily affects the simulation at the extremes of these ranges.

If smoothing is enabled, the block smoothly saturates the orifice area between the Leakage area and Maximum orifice area parameters and applies the smoothing function. The block smooths the valve pressure between the parameter Set orifice pressure differential and the sum of the parameters Set orifice pressure differential and Pressure compensator valve regulation range.

Orifice parameterization

Set Orifice parameterization to:

Linear - Area vs. control member position - assumes that the control member position and the hole opening area are linearly related;
Tabulated data - Area vs. control member position - interpolates user data between hole opening area and control member position with a potentially non-linear relationship;
`Tabulated data - Volumetric flow rate vs. control member position and pressure drop' - interpolates the volumetric flow rate through the orifice directly from user data between control member position, pressure drop across the orifice and volumetric flow rate through the orifice.

Ports

Conserving

# A — isothermal liquid port
isothermal liquid

Details

The point where fluid enters or leaves the valve.

Program usage name

port_a

# B — isothermal liquid port
isothermal liquid

Details

The point where fluid enters or leaves the valve.

Program usage name

port_b

Input

# S — physical signal, in m
scalar

Details

Opening of a hole (in m), returned as a physical signal. A positive signal opens the hole.

Data types	`Float64`.
Complex numbers support	No

Parameters

# Orifice parameterization — hole modelling technique
Linear - Area vs. control member position | Tabulated data - Area vs. control member position | Tabulated data - Volumetric flow rate vs. control member position and pressure drop

Details

A method for modelling a hole opening. The orifice is either parameterised linearly, which relates the orifice area to the position of the control element; using user data, which relates the orifice area to the position of the control element; or using an array of data, which relates the valve flow rate to the position of the control element and the pressure drop across the valve.

Values	`Linear - Area vs. control member position` \| `Tabulated data - Area vs. control member position` \| `Tabulated data - Volumetric flow rate vs. control member position and pressure drop`
Default value	`Linear - Area vs. control member position`
Program usage name	`restriction_parameterization`
Evaluatable	No

# Control member position at closed valve — control offset
m | cm | ft | in | km | mi | mm | um | yd

Details

Offset of the control when the orifice is fully open. A positive non-zero value indicates a partially closed orifice. A negative non-zero value indicates an overlapped orifice that remains open at the initial offset set by the physical signal on port S.

Dependencies

To enable this parameter, set Orifice parameterization to Linear - area vs. control member travel.

Values	`m` \| `cm` \| `ft` \| `in` \| `km` \| `mi` \| `mm` \| `um` \| `yd`
Default value	`0.0 m`
Program usage name	`min_control_displacement`
Evaluatable	Yes

# Control member travel between closed and open valve — maximum stroke of the control element
m | cm | ft | in | km | mi | mm | um | yd

Details

The stroke of the actuating element at which the orifice is fully open.

Dependencies

To enable this parameter, set Orifice parameterization to Linear - Area vs. control member travel.

Values	`m` \| `cm` \| `ft` \| `in` \| `km` \| `mi` \| `mm` \| `um` \| `yd`
Default value	`5e-3 m`
Program usage name	`delta_control_displacement`
Evaluatable	Yes

# Maximum orifice area — maximum cross-sectional area of the hole
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

The cross-sectional area of the orifice in the fully open position. This parameter is used as an upper limit for area and pressure calculations during simulation.

Dependencies

To enable this parameter, set Orifice parameterization to `Linear - Area vs. control member travel'.

Values	`m^2` \| `cm^2` \| `ft^2` \| `in^2` \| `km^2` \| `mi^2` \| `mm^2` \| `um^2` \| `yd^2`
Default value	`8e-5 m^2`
Program usage name	`max_restriction_area`
Evaluatable	Yes

# Control member position vector — vector of distances of movement of control elements
m | cm | ft | in | km | mi | mm | um | yd

Details

Control element position vector for tabular parameterization of the hole opening area. The elements of the vector must match one-to-one with the elements of the Orifice area vector. The elements are listed in ascending order and the first element must be equal to 0. Linear interpolation is used between tabular data points.

Dependencies

To enable this parameter, set Orifice parameterization to Tabulated data - Area vs. control member position.

Values	`m` \| `cm` \| `ft` \| `in` \| `km` \| `mi` \| `mm` \| `um` \| `yd`
Default value	`[0.0, 2e-3, 7e-3] m`
Program usage name	`control_displacement_vector_1D`
Evaluatable	Yes

# Orifice area vector — hole opening area vector
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

Valve orifice area vector for tabular parameterization of the valve opening area. The elements of the vector must match one-to-one with the elements of the Control member position vector. The elements are listed in ascending order and must be greater than `0'.

Dependencies

To enable this parameter, set Orifice parameterization to `Tabulated data - Area vs. control member position'.

Values	`m^2` \| `cm^2` \| `ft^2` \| `in^2` \| `km^2` \| `mi^2` \| `mm^2` \| `um^2` \| `yd^2`
Default value	`[1e-9, 4e-9, 1e-5] m^2`
Program usage name	`restriction_area_vector_1D`
Evaluatable	Yes

# Control member position vector, s — control element displacement vector
m | cm | ft | in | km | mi | mm | um | yd

Details

Control displacement vector for volumetric flow rate table parameterization. The position vector of the controls forms an independent axis with the parameter Pressure drop vector, dp for the dependent parameter Volumetric flow rate table, q(s,dp). A positive offset corresponds to valve opening. Values are listed in ascending order and the first element must be equal to 0. Linear interpolation is used between the tabulated data points.

Values	`m` \| `cm` \| `ft` \| `in` \| `km` \| `mi` \| `mm` \| `um` \| `yd`
Default value	`[0.0, 2e-3, 4e-3, 7e-3, 1.7e-2] m`
Program usage name	`control_displacement_vector_2D`
Evaluatable	Yes

# Pressure drop vector, dp — vector of differential pressure values
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

Vector of differential pressure values for tabular parameterization of the valve opening area. The differential pressure vector forms an independent axis with the Control member position vector, s for the dependent parameter Volumetric flow rate table, q(s,dp). Values are listed in ascending order and must be greater than 0. Linear interpolation is used between tabular data points.

Values	`Pa` \| `GPa` \| `MPa` \| `atm` \| `bar` \| `kPa` \| `ksi` \| `psi` \| `uPa` \| `kbar`
Default value	`[0.3, 0.5, 0.7] MPa`
Program usage name	`delta_p_vector_2D`
Evaluatable	Yes

# Volumetric flow rate table, q(s,dp) — volume flow rate array
m^3/s | m^3/h | cm^3/s | mm^3/s | ft^3/s | lpm | l/s | gpm | gal/s | gal/h

Details

Matrix of volume flow rates based on independent values of differential pressure and position of the control element. and are the dimensions of the corresponding vectors:

- number of elements in the Pressure drop vector, dp.
- number of elements in the Control member position vector, s.

Dependencies

To enable this parameter, set Orifice parameterization to Tabulated data - Volumetric flow rate vs. control member position and pressure drop.

Values	`m^3/s` \| `m^3/h` \| `cm^3/s` \| `mm^3/s` \| `ft^3/s` \| `lpm` \| `l/s` \| `gpm` \| `gal/s` \| `gal/h`
Default value	`[1.7e-05 2e-05 2.6e-05; 0.0035 0.0045 0.0053; 0.7 0.9 1.06; 1.96 2.5 3.0; 6.0 7.7 9.13]*1e-3 m^3/s`
Program usage name	`Vdot_matrix_2D`
Evaluatable	Yes

# Set orifice pressure differential — compensator valve threshold
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

The amount of differential pressure that causes the valve to open or close.

Values	`Pa` \| `GPa` \| `MPa` \| `atm` \| `bar` \| `kPa` \| `ksi` \| `psi` \| `uPa` \| `kbar`
Default value	`0.6 MPa`
Program usage name	`delta_p_set`
Evaluatable	Yes

# Pressure compensator valve regulation range — working pressure range of the compensating valve
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

The working pressure range of the valve. The pressure control range lies between Set orifice pressure differential and the maximum working pressure of the valve.

Values	`Pa` \| `GPa` \| `MPa` \| `atm` \| `bar` \| `kPa` \| `ksi` \| `psi` \| `uPa` \| `kbar`
Default value	`0.1 MPa`
Program usage name	`p_regulation_range`
Evaluatable	Yes

# Pressure compensator valve maximum area — area of fully open pressure compensation valve
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

The cross-sectional area of the valve orifice in the fully open position. This parameter is used as an upper limit for area and pressure calculations during simulation.

Values	`m^2` \| `cm^2` \| `ft^2` \| `in^2` \| `km^2` \| `mi^2` \| `mm^2` \| `um^2` \| `yd^2`
Default value	`12e-5 m^2`
Program usage name	`max_compensator_area`
Evaluatable	Yes

# Leakage area — clearance area in fully closed position
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

The sum of all clearances when the valve is in the fully closed position. Any area smaller than this value is maintained at the specified leakage area. This promotes computational deviceability by maintaining continuity of flow.

Values	`m^2` \| `cm^2` \| `ft^2` \| `in^2` \| `km^2` \| `mi^2` \| `mm^2` \| `um^2` \| `yd^2`
Default value	`1e-10 m^2`
Program usage name	`leakage_area`
Evaluatable	Yes

# Discharge coefficient — flow coefficient

Details

Correction factor that takes into account the rarefaction losses in theoretical flows.

Default value	`0.64`
Program usage name	`C_d`
Evaluatable	Yes

# Critical Reynolds number — upper limit of Reynolds number in the laminar flow regime

Details

Upper limit of the Reynolds number in laminar flow through the valve.

Default value	`150.0`
Program usage name	`Re_critical`
Evaluatable	Yes

# Smoothing factor — numerical smoothing factor

Details

A continuous smoothing factor that introduces a level of gradual change based on the flow characteristic when the valve is in the nearly open and nearly closed positions. Set a non-zero value less than one to increase the stability of the simulation in these modes.

Default value	`0.01`
Program usage name	`smoothing_factor`
Evaluatable	Yes