Poppet with Conical Seat (IL)

If the check box is Moving body removed, and the body movement is not simulated, then the lifting of the two-cone valve is defined as:

where

If the check box is Moving body If the valve body is installed, and the body movement is simulated, then the lift of the two-cone valve is defined 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.

The figure shows a diagram for calculating the flow area of a two-cone disc valve with a conical seat, which has half the angle of the needle. more than half of the saddle angle . If the angle values are equal , then the valve is a conical valve with a conical seat.

Depending on the elevation value, there are two possible ways to calculate the flow area. The effective flow area will be equal to the minimum value between these two options.:

Hydraulic diameter it is calculated in a simplified way for a conical valve (with half an angle ) on a saddle with a sharp edge:

In the above model, it is assumed that the lift values are much smaller than the seat diameter.

Lifting value at which the flow area reaches the neck area , is determined numerically and is limited by the area of the neck.

The value used for lifting , is limited by the lower value (parameter value Lift corresponding to minimum area) and the smaller of the values (parameter value Lift corresponding to maximum area) and . Usually it is zero, but it can be set higher to simulate the leakage rate. Meaning usually very large (for example, inf), but a much lower value can be set to simulate an additional hole.

Area value limited by the area of the hole:

If the check box Moving body removed, the volumes of liquid that are discharged to ports A and B are calculated as:

where and — parameter values Volume at port A corresponding to zero lift and Volume at port B corresponding to zero lift, respectively.

If the check box is 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 is 1000. However, for holes with complex (rough) geometry, it may be smaller. 50. For very smooth geometry, it can be set to 50000.

The average fluid velocity is:

The volume consumption is:

where

If the check box is Moving body if withdrawn, the volume costs in ports B and A are calculated as:

where

If the check box 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 inclination of the jet, equal to half the angle of the saddle cone.

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

It is assumed that the average pressure is in the port side area, A affects the balance of forces if the lift value is greater than the parameter value. Lift needed for the setting of mean pressure (the transition is assumed to be exponential). The average pressure is determined by the formula:

where — parameter value Lift needed for the setting of mean pressure.

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

Values and limited from above by the value .