Chapter 16	DIESEL ENGINE: SECTOR MODEL
	Creating the Sector Mesh

Figure 16-7 Overlay of 2D template and bowl splines

Creating the Sector Mesh

The final stage in the sector meshing process is to trim the 2D template to the bowl splines and generate the 3D sector mesh representing the cylinder sector.

•In the Sector panel, click Trim to create the trimmed sector mesh

•When the child process is complete, click Get sector to read the trimmed sector mesh into the Template window, as shown in Figure 16-8

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DIESEL ENGINE: SECTOR MODEL	Chapter 16
Creating the Sector Mesh

Figure 16-8 Mesh before and after trimming

Finally, complete the mesh so that it is ready for use in pro-STAR. This process is similar to the one described in Chapter 4, “Running Star Setup”, except that it is entirely contained within the Sector panel. If you wish to utilize any of the toggle button options provided in Star Setup for your own case, do so before executing the steps below.

•In the Sector panel (see Figure 16-9), set the Extrusion ratio to 0.4 to create

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Chapter 16	DIESEL ENGINE: SECTOR MODEL
	Creating and Checking the Mesh

an extrusion layer on the wall boundaries. The specified value defines the layer thickness as a ratio of the adjacent cell thickness

•Click Create to finalise the mesh set-up

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Figure 16-9 Finalising the mesh set-up in the Sector panel

Creating and Checking the Mesh

You now need to create the mesh to be used by the STAR solver. This allows you to check that the mesh is suitable for your case and valid for a full CFD analysis. You are advised to create and check the mesh at several crank angles to evaluate mesh quality at every stage.

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To create the computational mesh at TDC:

•In the Select panel, click Create Result

•In the Create Result panel, set the Angle (deg) to 720

•Select the Interpolate toggle button to interpolate vertex locations (as opposed to using internal es-ice smoothing algorithms). Interpolation is slower, but uses the same method as the STAR solver.

•Click Create Result to create the computational mesh

•When the child process is complete, click Read Result to import the mesh into in the Workspace window

•In the Plot Tool, select the Fill toggle button and click CPlot to view the mesh, as shown in Figure 16-10

Figure 16-10 The mesh at TDC

•Enter the following command to check for negative-volume cells (and, if any are found, put them in CSet 25):

Check, NegVolume, 25

Saving the Model

•In the Write Tool, enter save_es-ice.sector and then click Save

At this stage, you can continue setting up the model physics in es-ice and pro-STAR by going to Chapter 17 and following the description therein. Note, however, that you need to specify eight injectors in that tutorial, whereas only the first injector is required for this sector model.