Gate Valve (TL)

A gate valve in a thermal liquid network.

gate valve tl

Description

Unit Gate Valve (TL) is a shut-off valve in a thermal liquid network. The valve consists of a circular orifice with sharp edges and a circular plug of the same diameter. The gate valve opens or closes according to the offset signal at port S. A positive signal raises the gate, opening the valve.

The diagram shows the relationship between the opening area and the gate bias.

gate valve il 1 en

The smoothing function allows the valve opening area to vary smoothly between the fully closed and fully open positions. The smoothing function reduces sudden changes in the opening area at zero and maximum valve positions.

Weight conservation

The mass conservation equation for the valve is as follows:

where

- is the mass flow rate to the valve through port A;
- is the mass flow rate to the valve through port B.

Storing the pulse

The equation for conservation of momentum in the valve is:

where

and - pressure in ports A and B;
- mass flow rate;
- critical mass flow rate:
- average density of the liquid;
- flow coefficient;
- valve inlet area;
- pressure coefficient:

Conservation of energy

The equation of conservation of energy in a valve is of the form:

where

- is the energy flow to the valve through port A;
- is the energy flow to the valve through port B.

Valve opening area

The unit calculates the valve opening area using the expression:

where

- valve opening area;
- parameter value Leakage area;
- is the diameter of the valve bore;
- the part of the valve opening area covered by the plug:

where is the offset of the bolt centre relative to the bore centre:

where
- - parameter value Gate position when fully covering orifice;
- - is the gate offset set via input port S.

Numerically smoothed offset

When the valve is in the nearly open or nearly closed position, it is possible to maintain numerical stability in the simulation by adjusting the parameters Smoothing factor. If the parameters Smoothing factor is not zero, a smooth variation of the gate displacement between 0 and the parameter value is provided Orifice diameter.

Ports

Conserving

# A — thermal liquid port
thermal liquid

Details

Thermal liquid port, corresponds to valve inlet A.

Program usage name

port_a

# B — thermal liquid port
thermal liquid

Details

Thermal liquid port, corresponds to valve inlet B.

Program usage name

port_b

Input

# S — gate displacement, m
scalar

Details

Valve gate displacement, in m. A positive value on this port means that the valve is open.

Data types	`Float64`.
Complex numbers support	No

Parameters

# Orifice diameter — bore diameter
m | cm | ft | in | km | mi | mm | um | yd

Details

The diameter of the valve’s open orifice.

Units	`m` \| `cm` \| `ft` \| `in` \| `km` \| `mi` \| `mm` \| `um` \| `yd`
Default value	`0.01 m`
Program usage name	`orifice_diameter`
Evaluatable	Yes

# Gate position when fully covering orifice — gate offset
m | cm | ft | in | km | mi | mm | um | yd

Details

The gate offset when the valve is closed. A positive non-zero value indicates a partially open valve when the value at port S is 0. A negative non-zero value indicates an overlapped valve that remains closed at the initial positive offset that is set at port S.

Units	`m` \| `cm` \| `ft` \| `in` \| `km` \| `mi` \| `mm` \| `um` \| `yd`
Default value	`0.0 m`
Program usage name	`min_control_displacement`
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 less than this value equates to the specified leakage area. This parameter contributes to the stability of the numerical solution by maintaining flow continuity.

Units	`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

# Smoothing factor — numerical smoothing factor

Details

A continuous smoothing factor that ensures smooth opening by correcting the valve characteristic in the nearly open and nearly closed positions.

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

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

Details

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

Units	`m^2` \| `cm^2` \| `ft^2` \| `in^2` \| `km^2` \| `mi^2` \| `mm^2` \| `um^2` \| `yd^2`
Default value	`0.01 m^2`
Program usage name	`port_area`
Evaluatable	Yes

# Discharge coefficient — flow coefficient

Details

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

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

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

Details

Upper Reynolds number limit for laminar flow through the valve.

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