Building the Mesh

This section describes the step-by-step procedure for preparing the mesh for the spool valve. The Valve Template Mesher is used for creating the spool valve mesh and the General Mesher is used for creating the mesh for the ports, cross channels and high pressure chamber.

Ports

Select General Mesher in the Mesh Panel.
Select CAD Surfaces port_inlet, port_mgi_valve1, port_mgi_valve2, port_outlet and port_wall in the Geometric Entities Panel and click Add Surfaces icon for CAD Surfaces in the Properties Panel.
Enter Maximum Cell Size as 0.01, Minimum Cell Size as 0.001 and Cell Size on Surfaces as 0.005.
Click Create Mesh. A new mesh port is created under Built Meshes in the Geometric Entities Panel.
The meshed volumes port and port_1 are generated under Volumes.

Figure 6.533 - Ports mesh settings

High pressure chamber and cross channels

Select General Mesher in the Mesh Panel.
Select CAD Surfaces valve2_cylinder, valve2_ends, valve2_mgi_valve1 and valve2_valve in the Geometric Entities Panel and click Add Surfaces icon for CAD Surfaces in the Properties Panel.
Enter Maximum Cell Size as 0.01, Minimum Cell Size as 0.001 and Cell Size on Surfaces as 0.005.
Click Create Mesh. A new mesh valve2 is created under Built Meshes in the Geometric Entities Panel.
The meshed volume valve2 is generated under Volumes

Figure 6.534 - High pressure chamber and cross channels mesh settings

Spool valve

Select Valve Template Mesher in the Mesh Panel.
Select Spool Valve from Valve Type drop-down list in the Properties Panel.
Select CAD Surfaces valve1_valve in the Geometric Entities Panel, click Add Surface icon for Valve Surfaces in the Properties Panel.
Select CAD Surfaces valve1_cylinder_i, valve1_cylinder_o and click Add Surfaces icon for Cylinder Surfaces.
Select CAD Surfaces valve1_ends1, valve1_ends2 and click Add Surface icon for Valve End Surfaces.
Enter the parameters as follows.

Opening Direction: -1,0,0
Minimum Gap Size: 0.0001 m
Maximum Displacement: 0.01 m
Maximum Cell Size: 0.04
Minimum Cell Size: 0.001
Cell Size on Surfaces: 0.02
Deform Zone Layers: 8
Deform Zone Coarsening Level: 0

Click Build Spool Valve Mesh. A new mesh spool valve is created under Built Meshes in the Geometric Entities Panel.

The meshed volume spool valve is generated under Volumes

Figure 6.535 - Spool valve mesh settings

Note:

The Deform Zone Layers and Deform Zone Coarsening Level control the number of layers of mesh between the valve and valve end. Further refinement of the layers depends on the cell size specifications.

The mesh created for the fluid domain is shown below.

Figure 6.536 - Port mesh

Figure 6.537 - High pressure chamber and cross channels mesh

Figure 6.538 - Cross section showing spool valve mesh

Create interfaces

In this section, the Mismatched Grid Interfaces (MGIs) are generated between boundaries.

The steps to create the MGI is as follows:

In Geometric Entities Panel > Volumes > Boundaries, select the Boundaries as shown in Table 6.27.
Click Connect Selected Boundaries via MGI icon upon selecting the required boundaries, to create the MGI entities (see, Figure 6.539).

A group display of entities can be viewed using the Group Entities by Volumes/Types icon in Geometric Entities Panel toolbar.

Connecting interfaces	Boundaries	Entity
Cross channels and low pressure chamber cylinder	valve2_mgi_valve1, valve1_cylinder_i	MGI01
Low pressure port and low pressure chamber cylinder	port_mgi_valve1, valve1_cylinder_o	MGI02
High pressure port and high pressure chamber cylinder	port_mgi_valve2, valve2_cylinder	MGI03

Table 6.27 - Creating interfaces

The new entities are created under Mismatched Grid Interfaces in Volumes (see, Figure 6.540).

Figure 6.539 - Connecting boundaries

Figure 6.540 - Created interfaces

´	Note: If MGIs are created by connecting the wrong boundaries, delete the created MGIs by clicking Delete Selected Geometric Entity icon and then recreate the MGIs.