Ball Poppet with Sharp Edge Seat (IL)

If the check box Moving body removed, and the body movement is not simulated, then the ball lift is calculated as:

where

If the check box Moving body is installed, and the body movement is simulated, then the ball lift is calculated as:

where — moving the case in port CA.

The minimum flow area is determined by the curved surface of the truncated cone, as shown in the figure. It is assumed that this surface divides the area occupied by the liquid into two areas with different pressures. There is pressure on one of these areas. , and on the other — pressure . This assumption is reasonable if the lift of the ball is small compared to the diameter of the saddle. If the rise of the ball is large, it is obvious that at some point the smallest limitation will be the area of the neck.

The area of the hole is defined as:

where is determined from the equation:

The hydraulic diameter is calculated as:

where — the active diameter, defined as:

Note that the value used for , limited between and the smaller of the values and , where is the elevation value at which the calculated area becomes equal to the annular area.:

Meaning Always more .

Usually the value is it is zero, but it can be set higher to simulate the leakage rate. Meaning it is usually very high (for example, Inf), but a much lower value can be set to simulate an additional hole.

Liquid volume , the pressure in which is equal to the pressure , additional to the volume when the valve is closed, is calculated as:

Where is the angle — this is the corner at zero lift, determined from the equation:

The value of the additional volume it is important when calculating pressure dynamics (frequency analysis).

The derivative of the additional volume by calculated as:

If the check box is Moving body removed, the volume of liquid that is discharged to port B is calculated as:

where — parameter value Volume at port B corresponding to zero lift.

And the volume of liquid that is discharged into port A is calculated as:

where — parameter value Volume at port A corresponding to zero lift.

If the check box Moving body installed:

Flow coefficient calculated as

where

The average density is calculated at an average pressure .

Expense ratio calculated as

where

For meaning practically does not change. For low meaning it changes linearly with the change .

A reasonable value the default value is `1000'. However, for holes with complex (rough) geometry, it may be less than `50'. For very smooth geometry, it can be set to `50,000'.

The average fluid velocity is:

The volume consumption is:

where

If the check box Moving body if withdrawn, the volume costs in ports B and A are calculated as:

where

If the check box is Moving body installed:

where — the speed of the hull in the port CA.

The hydrodynamic force is determined by estimating the change in momentum. This force tends to close the valve. For a steady-state fluid flow, the hydrodynamic force is:

where — the angle of the jet:

Dependence of the hydrodynamic force from the rise It is defined as follows:

where — parameter value Lift corresponding to minimum area.

The power in port RA is calculated as:

where — the power that enters the RB port.

If the check box is selected Moving body, and the hull movement is modeled, then the force in the port CA is calculated as:

where — the power that enters the port C_p.