Solenoid (IH)#

The Solenoid (IH) block simulates the operation of the corresponding component in a hydraulic network, which operates according to the following principle:

In addition to two standard hydraulic ports (input and output), the block has a control port by means of an automation signal receiving values in the range [0; 1]. If the signal is greater than or equal to 0.5, then the valve (solenoid) begins to gradually open, otherwise close. In this case, the current position, and with it the flow cross-sectional area, depend on the properties of the block specified by the user:

Valve initial position can be Open and Closed and describes the state of the valve prior to calculation;
Open time ($t_{Open}$) and Close time ($t_{Close}$) determine the rate of change of its position when moving in one direction or another;
Maximum valve area reflects the maximum solenoid capacity when fully open.

Note

The nature of opening and closing the valve is linear, that is, the speed of movement of the control element does not depend on the time and current position.

Calculation of valve cross-sectional area:

When it is opened, the valve cross-sectional area $A_{valve}$ is defined as (1) :

(1)#\[A_{valve}=A_{init}+time/t_{Open}\cdot (A_{max}-A_{leak})\]

When it is closed, the valve cross-sectional area $A_{valve}$ is defined as (2) :

(2)#\[A_{valve}=A_{init}-time/t_{Close}\cdot (A_{max}-A_{leak})\]

where:

$A_{init}$ is the initial valve area, [м$^2$], which, at the start of calculation from the zero moment of the model time, takes the value determined by Valve initial position property - either $A_{max}$ (he valve is completely open), or 0 (the valve is completely closed). In case of shutdown and subsequent continuation of the calculation, $A_{init}$ takes the last calculated value;

$t_{Open}$ – valve opening time, [s];

$t_{Close}$ – valve closing time, [s];

$A_{max}$ – maximum valve area, [m$^2];

$A_{leak}$ – leakage area, [m$^2$].

Law of mass conservation(3) :

(3)#\[m_1+m_2=0\]

where $m_1$ and $m_2$ is flow rate at block input and output, [kg/s].

Dependence of mass on pressure drop(4) :

(4)#\[\dot{m}=\frac{C_d \cdot A_{valve} \cdot \sqrt{2 \cdot \bar \rho}}{\sqrt{PR_{loss}(1-(\frac{A_{valve}}{A_{port}})^2)}}\cdot \frac{\Delta p}{(\Delta p^2+\Delta p^2_{crit})^{1/4}}\]

where:

$A_{valve}$ – solenoid cross-sectional area, [m$^2$];

$A_{port}$ – port cross-sectional area, [m$^2$];

$PR_{loss}$ – dimensionless loss factor;

$\Delta p_{crit}$ – critical pressure drop, [Pa];

$\Delta p$ – pressure drop between input and output port, [Pa].

Note

Calculated in the model core at each cycle of its operation

Note

Calculated in the model core at each cycle of its operation

Calculation of critical drop(5) :

(5)#\[\Delta p_{crit}=\frac{\pi \cdot \bar \rho}{8 \cdot A_{valve}}\cdot(\frac{\nu \cdot Re_{crit}}{C_d})^2\]

where:

emsp;$C_d$ – Discharge coefficient;

$ u$ – liquid kinematic viscosity, mm$^2$/s;

$Re_{crit}$ – Critical Reynolds numbers, the boundary between laminar and turbulent flow.

Calculation of loss ratios (6) :

(6)#\[PR_{loss}=\frac{\sqrt{1-(\frac{A_{valve}}{A_{port}})^2\cdot (1-C_d^2)}-C_d\cdot \frac{A_{valve}}{A_{port}}}{\sqrt{1-(\frac{A_{valve}}{A_{port}})^2\cdot (1-C_d^2)}+C_d\cdot \frac{A_{valve}}{A_{port}}}\]

Note

If Pressure recovery block property is set by the user to On position, $PR_{loss}$ parameter takes the value 1 (with no size).

1. Properties#

Property	Default Value	Description	Units of measurement
Valve initial position: Closed; Open	Closed	-	-
Open time	0.05	-	s
Close time	0.1	-	s
Maximum valve area	1.0E-4	-	m$^2$
Leakage area	1.0E-10	-	m$^2$
Port area	0.09	-	m$^2$
Discharge coefficient, available when selecting `Pressure recovery` - `On`	0.64	-	-
Critical Reynolds numbers	150.0	-	-
Pressure recovery	Off	-	-

2. Inputs and outputs#

Parameters	Input/Output	Description	Units of measurement	Port type
Input	Input	-	-	Isothermal Hydraulics
Signal from 0 inc to 1 inc	Input	-	-	Automation
Output	Output	-	-	Isothermal Hydraulics

In order to see the connection capabilities of the block, you need to go to page Description of block ports