Chapter 3	GEOMETRY IMPORT AND VALVE WORK
	Importing the Surfaces

Chapter 3 GEOMETRY IMPORT AND VALVE WORK

The following tutorial data files are used in this chapter: geometryRemesh.dbs (geometry surface from Chapter 2)

The model created at the end of this tutorial is saved to file: save_es-ice.1-valves

Chapter 2, “The es-ice Environment” in the User Guide describes the preliminary steps necessary before starting an es-ice session. This chapter describes the initial steps required to generate a mesh for a symmetric, four-valve engine cylinder.

These are:

1.Importing the geometry surface

2.Assigning a cell type to the valves

3.Defining local coordinate systems for the valves

4.Creating and checking valve profiles

Importing the Surfaces

After starting es-ice, begin by importing the discretised surface defining the problem geometry. The following file formats can be used:

•Database files with extension .dbs

•Cell and vertex files with extension .cel and .vrt, respectively, which can be in binary or coded format.

In this section, you import the geometry surface (geometryRemseh.dbs) created in Chapter 2 using the Read Tool. The tool is divided into five sections:

•The top section imports .vrt, .cel and .cpl files into the Template window

•The second section imports .vrt and .cel files into the Geometry window

•The third section opens .dbs files

•The forth section opens .ccm files

•The bottom section resumes es-ice model files

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GEOMETRY IMPORT AND VALVE WORK	Chapter 3
Importing the Surfaces

To import the geometry surface mesh:

•Launch es-ice in the usual manner

•In the Select panel, click Read Data to open the Read Tool

•Click the ellipsis (...) next to the DBase box and select geometryRemseh.dbs via the file browser

•Click the ellipsis (...) next to the Get box and select 1 Geometry via the database browser

To import the valve surface mesh:

•In the Read Tool, select the Add toggle button under DBase

•Click the ellipsis (...) next to the Get box and select 2 Valves via the database browser

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Chapter 3	GEOMETRY IMPORT AND VALVE WORK
	Modelling the Valves

Check that the surface has been imported to the

Geometry window:

•In the Plot Tool, select Geometry from the drop-down menu

•Enter the following command to set up a suitable viewpoint

View, 1, -2, 1

• Click CPlot to display the imported geometry surface, as shown in Figure 3-1

Figure 3-1 Geometry window: Imported geometry surface

Modelling the Valves

To determine the direction of motion during valve opening and closing events, es-ice uses cylindrical coordinate systems with origins at the valve centres and z-axes in the direction of valve motion. In addition, es-ice assumes that valves are axisymmetric (i.e. represented by a surface of revolution) so the shape of each valve is defined by a two-dimensional profile. A spline is then sufficient to display the valve profile for a visual check.

Since you have named the valves in STAR-CCM+, each valve can be easily isolated via an es-ice command. This makes the process of valve modelling much simpler.

To model Valve 1:

•Enter the following command to isolate the Valve 1 shells:

CSet, Newset, Name, Valve1

•In the Select panel, click Create Template

•In the Create Template panel, click Valve profile

•In the Create valve profile panel shown in

the adjacent screenshot, ensure that Valve 1 is selected from the drop-down menu and the Coordinate system is set to 11

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GEOMETRY IMPORT AND VALVE WORK	Chapter 3
Modelling the Valves

•Set Select shells to cset0 to create the valve profile for the current cell set

•Click Create profile

This action creates coordinate system 11, located at the bottom centre of the valve, whose z-axis is parallel to the direction of valve motion. It also automatically generates a spline that follows the valve profile, thus defining the valve shape. This profile is used during the trimming process to trim the template to the valve shape.

We recommend checking that the valve profile correctly matches the valve shape shown in Figure 3-2.

Figure 3-2 Valve 1 profile

If the valve profile is poorly defined in one of your own cases, you can either adjust the Edge angle parameter in the Create valve profile panel, or create the profile manually (see Chapter 5 in the User Guide). This profile is stored as an image within the es-ice model file so you can clear the valve spline if you wish.

You can now use a similar technique to model Valve 2:

•Enter the following command to isolate the Valve 2 shells:

CSet, Newset, Name, Valve2

•In the Create valve profile panel, select Valve 2 from the drop-down menu

•Set Select shells to cset0

•Click Create profile

To display and list the newly created coordinate systems:

•In the Plot Tool, select the Local toggle button and click CPlot to display all coordinate systems in the Geometry window

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