Solenoid Valve (IL)

An electromagnetic valve in an isothermal fluid network.

blockType: EngeeFluids.IsothermalLiquid.Valves.DirectionalControl.Solenoid

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/Physical Modeling/Fluids/Isothermal Liquid/Valves & Orifices/Directional Control Valves/Solenoid Valve (IL)

Description

Block Solenoid Valve (IL) simulates the flow through an electromagnetic valve in an isothermal fluid network. The valve consists of a two-line control valve with an electromagnetic actuator. The signal on the S port controls the electromagnet. When the signal on port S exceeds the value 0.5 The electromagnet turns on and the valve opens. When the signal on port S drops below 0.5 The electromagnet turns off and the valve closes.

Solenoid valves consist of a valve body with a spring-loaded plunger, which is controlled by an electromagnet. When the electromagnet is turned on, the magnetic force lifts the spool, allowing the liquid to flow. When the electromagnet is turned off, the spring pushes the plunger back into place, stopping the flow. The unit does not explicitly model the mechanics of an electromagnet, but characterizes the opening and closing of the valve using the switching time of opening and closing.

Mass consumption

The mass flow through the valve is calculated as follows:

where

— the cross-sectional area of the valve;
— parameter value Cross-sectional area at ports A and B;
— flow coefficient, the value of the parameter Discharge coefficient;
— the average density of the liquid;
— pressure difference in the valve;
— critical pressure drop:

where — parameter value Critical Reynolds number, and — dynamic viscosity of the liquid.

Dynamics of the opening

The block assumes that the electromagnet behaves like a series resistor-inductor circuit.:

where

— voltage across the electromagnetic inductor;
— resistance of the electromagnetic inductor;
— the inductance of the electromagnet;
— current through an electromagnetic inductor.

The electromagnet generates a force proportional to the square of the current , where — the constant of proportionality. The expression for the cross-sectional area of the valve depends on the parameter value Solenoid control.

valve controlled by a scalar signal

If for the parameter Solenoid control the value is set Signal, then the block calculates the opening area based on the scalar signal received at port S. When the valve opens:

When the valve closes:

where

— parameter value Maximum opening area;
— parameter value Leakage area;
— the time of switching on or off the electromagnet;
— the area of the valve at the moment of switching on or off the electromagnet;
, where — parameter value Opening switching time.
, where — parameter value Closing switching time.

_ Valve controlled by an electrical signal_

If for the parameter Solenoid control the value is set Electrical, then the unit calculates the opening area based on the electrical network connected to the solenoid valve via ports + and −.

The opening area is

where

— plunger position;
— parameter value Plunger distance of travel.

The block simulates the movement of the plunger in accordance with the force balance equation

where

— the mass of the moving parts of the solenoid valve;
— the force exerted by the spring to close the valve when the electromagnet is turned off;
— the force of the rigid stop, which does not allow the plunger to go beyond the fully open and fully closed positions. The unit calculates the force of the rigid stop using mode diagrams;
— the force generated by the electromagnet:

The block uses the solution of the balance of power equation to calculate , and for parameter values Rated voltage, Nominal current, Opening switching time and Closing switching time. The block then uses the values for , and to solve the problem of the plunger position at any given time.

Switching time

The block characterizes the solenoid valve using the opening and closing time set by the parameters Opening switching time and Closing switching time accordingly. Parameter Opening switching time — this is the time from switching on the electromagnet to increasing the flow rate to a level of 90% of the range up to the maximum.

solenoid valve il 1 en

Parameter Closing switching time — this is the time from switching off the electromagnet until the flow rate drops to a level of 10% of the range to the minimum value.

solenoid valve il 2 en

Assumptions and limitations

The maximum force of the electromagnet is equal to the force generated by the spring.
The damping inside the electromagnet and the flow pressure forces are negligible.
The spool is balanced.
The stroke length of the electromagnet is small enough for the unit to consider the inductance linear.

Ports

Conserving

# A — Isothermal liquid port
Isothermal liquid

Details

Liquid inlet or outlet port.

Program usage name

port_a

# B — Isothermal liquid port
Isothermal liquid

Details

Liquid inlet or outlet port.

Program usage name

port_b

# + — positive terminal
electricity

Details

A non-directional port connected to the positive terminal of the valve control.

Dependencies

To use this port, set the parameter Solenoid control value Electrical.

Program usage name

p

# – — negative terminal
electricity

Details

A non-directional port connected to the negative terminal of the valve control.

Dependencies

To use this port, set the parameter Solenoid control value Electrical.

Program usage name

n

Input

# S — valve control signal, dimensionless
scalar

Details

The signal controlling the valve. When the signal on the S port is higher 0.5, the electromagnet turns on and the valve opens. When the signal on the S port drops below 0.5, the electromagnet turns off and the valve closes.

Dependencies

To use this port, set the parameter Solenoid control value Signal.

Data types	`Float64`
Complex numbers support	I don’t

Parameters

# Solenoid control — valve control method
Signal | Electrical

Details

Select the method that the unit uses to control the valve. If you choose Signal, then the unit uses the scalar signal S to control the valve. If you choose Electrical Then the unit uses the electrical ports + and − and simulates the electrical response.

Values	`Signal` \| `Electrical`
Default value	`Signal`
Program usage name	`control_type`
Evaluatable	No

# Valve initial position — the initial position of the valve
Open | Closed

Details

Select the initial position of the valve — open or closed.

Values	`Open` \| `Closed`
Default value	`Closed`
Program usage name	`initial_position`
Evaluatable	No

# Opening switching time — time to increase the flow rate when opening
s | ns | us | ms | min | hr | d

Details

The time from switching on the electromagnet to increasing the flow rate to a level of 90% of the range up to the maximum.

If for the parameter Solenoid control the value is set Electrical, then calculate this parameter by the value of the parameter Rated voltage using a stepped input signal.

Units	`s` \| `ns` \| `us` \| `ms` \| `min` \| `hr` \| `d`
Default value	`0.05 s`
Program usage name	`t_open_switch`
Evaluatable	Yes

# Closing switching time — flow drop time at closing
s | ns | us | ms | min | hr | d

Details

The time from switching off the electromagnet until the flow rate drops to a level of 10% of the range to the minimum value.

If for the parameter Solenoid control the value is set Electrical, then calculate this parameter by the value of the parameter Rated voltage using a stepped input signal.

Units	`s` \| `ns` \| `us` \| `ms` \| `min` \| `hr` \| `d`
Default value	`0.1 s`
Program usage name	`t_close_switch`
Evaluatable	Yes

# Maximum opening area — the area of the fully open valve
m^2 | um^2 | mm^2 | cm^2 | km^2 | in^2 | ft^2 | yd^2 | mi^2 | ha | ac

Details

The cross-sectional area of the valve in the fully open position.

Units	`m^2` \| `um^2` \| `mm^2` \| `cm^2` \| `km^2` \| `in^2` \| `ft^2` \| `yd^2` \| `mi^2` \| `ha` \| `ac`
Default value	`0.0001 m^2`
Program usage name	`max_area`
Evaluatable	Yes

# Leakage area — leakage area through the valve in the fully closed position
m^2 | um^2 | mm^2 | cm^2 | km^2 | in^2 | ft^2 | yd^2 | mi^2 | ha | ac

Details

The sum of all clearances when the valve is in the fully closed position. Any area less than this value is equal to the specified leakage area. This parameter contributes to the stability of the numerical solution by maintaining the continuity of the flow.

Units	`m^2` \| `um^2` \| `mm^2` \| `cm^2` \| `km^2` \| `in^2` \| `ft^2` \| `yd^2` \| `mi^2` \| `ha` \| `ac`
Default value	`1.0e-10 m^2`
Program usage name	`leakage_area`
Evaluatable	Yes

# Cross-sectional area at ports A and B — the area at the inlet or outlet of the valve
m^2 | um^2 | mm^2 | cm^2 | km^2 | in^2 | ft^2 | yd^2 | mi^2 | ha | ac

Details

The cross-sectional area at ports A and B. This area is used when calculating the mass flow through the valve.

Units	`m^2` \| `um^2` \| `mm^2` \| `cm^2` \| `km^2` \| `in^2` \| `ft^2` \| `yd^2` \| `mi^2` \| `ha` \| `ac`
Default value	`Inf m^2`
Program usage name	`port_area`
Evaluatable	Yes

# Discharge coefficient — expense ratio

Details

The correction factor is the ratio of the actual mass flow to the theoretical mass flow through the valve.

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

# Critical Reynolds number — upper limit of the Reynolds number for laminar flow

Details

The upper limit of the Reynolds number for laminar flow through the valve.

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

# Pressure recovery — should the pressure increase be taken into account when expanding the area

Details

Should the pressure increase be taken into account when liquid flows from an area with a smaller cross-sectional area to an area with a larger cross-sectional area.

Default value	`false (switched off)`
Program usage name	`pressure_recovery`
Evaluatable	No

# Rated voltage — rated voltage of the electromagnet
V | uV | mV | kV | MV

Details

The rated voltage of the electromagnet. Calculate the parameter values Opening switching time and Closing switching time at this voltage, using a step input signal.

Dependencies