Four way two position hydraulic control valve (TL)#

The block models the operation of a valve with four orifices in a thermal-hydraulic network. The valve is controlled by a single spool, the position of which is determined by the pressure drop in an external circuit and the signal at port S, which sets the setpoint for this pressure drop. The block has two inlets — A and B and two outlets — P and T, as well as an additional pair of ports from the external circuit — X and Y.

When ports are paired (AP, BP, AT, and BT), the block models fluid flow through four different orifices. Parameters affecting the flow through each orifice (spool stroke and maximum flow area) can be set identically for all four orifices or individually. The user also sets the initial spool offset (Valve close position parameter) relative to the position where the orifice is fully open.

The spool moves when the pressure drop between the controlled ports X and Y of the external circuit exceeds the setpoint value transmitted to the block through the automation port. Regulation stops if the actual pressure drop exceeds the maximum value, which is the sum of the setpoint pressure drop and the user-defined control range (parameter Pressure drop range control contour).

The spool movement increases linearly with the relative excess of the setpoint.

In the initial spool position, all orifices are closed, and as the spool moves, they begin to open sequentially according to the orifice diameter and the specified offset. If the spool continues to move after the orifice is fully open (within the specified maximum stroke), saturation occurs, and the flow through the valve orifice does not increase.

The flow area of each orifice depends linearly on the spool position and is described by the formula (1):

(1)#\[A_{orifice}=\frac{A_{max}-A_{leak}}{\Delta S}\cdot S_{pos} + A_{leak}\]

where:

\(S_{pos}\) - calculated parameter based on the signal from the automation port Valve close position, [m];

\(\Delta S\) is the parameter Valve travel, [m];

\(A_{max}\) is a parameter Valve max area, [m\(^2\)];

\(A_{leak}\) - parameter Leakage area, [m\(^2\)].

1. Properties#

Property	Default Value	Description	Units of measurement
Positive spool position open connections: All closed; PA and BT; PA and PB; PB and AT; PA; PB; All opened	PA and BT	-	-
Negative spool position open connections: All closed; PA and BT; PA and PB; PB and AT; PA; PB; All opened	PA and BT	-	-
Characteristics for area: Identical; Different	Identical	-	-
Cross area calculation method : Linear; Table	Linear	-	-
Pressure drop range control contour	1000.0	-	Pa
Valve travel PA	0.05	Available, when `Characteristics for area` - `Different`	m
Valve travel PB	0.05	Available, when `Characteristics for area` - `Different`	m
Valve travel AT	0.05	Available, when `Characteristics for area` - `Different`	m
Valve travel BT	0.05	Available, when `Characteristics for area` - `Different`	m
Valve max area PA	1e-4	Available, when `Characteristics for area` - `Different`	m\(^2\)
Valve max area PB	1e-4	Available, when `Characteristics for area` - `Different`	m\(^2\)
Valve max area AT	1e-4	Available, when `Characteristics for area` - `Different`	m\(^2\)
Valve max area BT	1e-4	Available, when `Characteristics for area` - `Different`	m\(^2\)
Valve travel	0.13	Available, when `Characteristics for area` - `Identical` and `Cross area calculation method` - `Linear`	m
Valve max area	1e-4	Available, when `Characteristics for area` - `Identical` and `Cross area calculation method` - `Linear`	m\(^2\)
Leakage area	1e-10	Available, when `Cross area calculation method` - `Linear`	m\(^2\)
Area port	0.1	-	m\(^2\)
Discharge coefficient	0.64	-	-
Reynolds critical numbers	150.0	-	-
Smoothing factor	0.01	-	-
Pressure recovery	0.64	-	-
Valve close position PA	5e-3	-	m
Valve close position PB	5e-3	-	m
Valve close position AT	5e-3	-	m
Valve close position BT	5e-3	-	m
Valve travel	0, 0.02, 0.04, 0.07, 0.017	Available, when `Characteristics for area` - `Identical` and `Cross area calculation method` - `Table`	m
Valve cross area vector	1e-06, 1e-05, 1e-04, 1e-3, 3e-3	Available, when `Characteristics for area` - `Identical` and `Cross area calculation method` - `Table`	m\(^2\)
Valve travel PA	0, 0.02, 0.04, 0.07, 0.017	Available, when `Characteristics for area` - `Different` and `Cross area calculation method` - `Table`	m
Valve travel PB	0, 0.02, 0.04, 0.07, 0.017	Available, when `Characteristics for area` - `Different` and `Cross area calculation method` - `Table`	m
Valve travel AT	0, 0.02, 0.04, 0.07, 0.017	Available, when `Characteristics for area` - `Different` and `Cross area calculation method` - `Table`	m
Valve travel BT	0, 0.02, 0.04, 0.07, 0.017	Available, when `Characteristics for area` - `Different` and `Cross area calculation method` - `Table`	m
Valve cross area vector PA	1e-06, 1e-05, 1e-04, 1e-3, 3e-3	Available, when `Characteristics for area` - `Different` and `Cross area calculation method` - `Table`	m\(^2\)
Valve cross area vector PB	1e-06, 1e-05, 1e-04, 1e-3, 3e-3	Available, when `Characteristics for area` - `Different` and `Cross area calculation method` - `Table`	m\(^2\)
Valve cross area vector AT	1e-06, 1e-05, 1e-04, 1e-3, 3e-3	Available, when `Characteristics for area` - `Different` and `Cross area calculation method` - `Table`	m\(^2\)
Valve cross area vector BT	1e-06, 1e-05, 1e-04, 1e-3, 3e-3	Available, when `Characteristics for area` - `Different` and `Cross area calculation method` - `Table`	m\(^2\)

2. Inputs and outputs#

Parameters	Input/Output	Description	Units of measurement	Port type
Port A	Input	-	-	Thermohydraulics
Port B	Input	-	-	Thermohydraulics
Pressure drop set	Input	-	Pa	Automation
Control Port X	Input	-	-	Thermohydraulics
Control Port Y	Output	-	-	Thermohydraulics
Port P	Output	-	-	Thermohydraulics
Port T	Output	-	-	Thermohydraulics

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