The Ball Valve (IL) unit is a ball valve in an isothermal liquid network. The ball valve consists of a ball with an orifice that can rotate inside the valve body. When the valve is open, the orifice is completely blocked with the valve body port. When the valve is closed, the ball rotates and reduces the amount of overlap, thereby reducing the effective area of the port. Ball valves are often used for flow shut-off applications because they can reliably shut off flow over many cycles. Ball valves are less common in applications where precise throttling is required.
The block can be parameterised analytically or with tabular data. If the Ball valve parameterization is set to `Area of overlapping circles', the block defines the overlapping area between the valve orifice and the ball orifice as the opening area such that
,
,
,
where
and are the radii of the valve port and ball port, respectively;
- displacement of the centre of the ball bore relative to the centre of the valve port;
- rotation of the ball valve set through the S port. The valve is fully closed at rad and fully open at rad.
Mass flow equation
The unit calculates the flow rate through the valve using the pressure-area relationship for the orifices, which is as follows
where
- flow coefficient;
- is the average density of the fluid;
- valve opening area, where , and is the Leakage area parameter.
- critical pressure drop, determined from the critical Reynolds number value .
The unit calculates the critical pressure drop as follows:
If the Flow coefficient parameterization is set to Cd coefficient and area, the value for can be set using the Discharge coefficient parameter.
If the Flow coefficient parameterization is set to Cv coefficient USCS, the block calculates the value of as
С
where is the value of the Maximum Cv flow coefficient parameter.
If Flow coefficient parameterization is set to Kv coefficient SI, the block calculates the value of as
С
where is the value of the Maximum Kv flow coefficient parameterization.
In these equations, is 1 psi and is 1 bar.
Valve position value, in rad. The value 0 indicates a fully closed valve and the value π/2 indicates a fully open valve.
Data types
Float64.
Complex numbers support
No
Parameters
Parameters
#Ball valve parameterization —
ball valve parameterization
Area of overlapping circles | Tabulated data
Details
Option for selecting the parameterization method of the block:
Area of overlapping circles - areas of overlapping circles.
Tabulated data - use of tabulated data.
Values
Area of overlapping circles | Tabulated data
Default value
Area of overlapping circles
Program usage name
valve_parameterization
Evaluatable
No
#Flow coefficient parameterization —
flow coefficient parameterization
Kv coefficient (SI) | Cv coefficient (USCS) | Cd coefficient and area
Details
Option to select the method of flow coefficient parameterization:
Kv coefficient (SI) - parameterization via capacity factor - water flow rate in m^3/h through a fully open valve at a temperature of 15°C and a pressure drop of 1 bar.
Cv coefficient (USCS) - parameterization via capacity factor - water flow rate in gallons per minute through a fully open valve at 60°F with a pressure drop of 1 psi.
Cd coefficient and area - parameterization via dimensionless flow coefficient , which determines the efficiency of the valve.
Values
Kv coefficient (SI) | Cv coefficient (USCS) | Cd coefficient and area
The maximum value of the valve capacity factor. This value must correspond to the fully open position.
Dependencies
To use this parameter, set the Ball valve parameterization to Area of overlapping circles' and the Flow coefficient parameterization to `Kv coefficient (SI).
The maximum value of the valve capacity factor. This value must correspond to the fully open position.
Dependencies
To use this parameter, set the Ball valve parameterization to Area of overlapping circles' and the Flow coefficient parameterization to `Cv coefficient (USCS).
#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.
Dependencies
To use this parameter, set the Ball valve parameterization to `Area of overlapping circles'.
#Valve flow factor (Kv) vector —
valve capacity factor for a given ball rotation
m^3/hr
Details
Valve capacity factor for a given ball rotation. Each element of the vector is related to the elements of the vector from the Ball rotation vector parameter. The first element corresponds to valve leakage and must be non-zero.
Dependencies
To use this parameter, set the Ball valve parameterization parameter to `Tabulated data' and the Flow coefficient parameterization parameter to `Kv coefficient (SI)'.
Valve capacity factor for a given ball rotation. Each element of the vector is related to the elements of the vector from the Ball rotation vector parameter. The first element corresponds to valve leakage and must be non-zero.
Dependencies
To use this parameter, set the Ball valve parameterization parameter to `Tabulated data' and the Flow coefficient parameterization parameter to `Cv coefficient (USCS)'.
#Area vector —
area for a given ball rotation
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2
Details
The flow area for a given ball rotation. Each element of the vector is related to the vector elements from the Ball rotation vector parameter. The first element corresponds to valve leakage and must be non-zero.
Dependencies
To use this parameter, set the Ball valve parameterization to `Tabulated data' and the Flow coefficient parameterization to `Cd coefficient and area'.
The ball rotation for a given flow capacity or area. The elements of this vector must relate to the elements of the Valve flow coefficient (Cv) vector, the Valve flow factor (Kv) vector, or the Area vector.
Dependencies
To use this parameter, set the Ball valve parameterization parameter to `Tabulated data'.