Setting up the Engine

(for full-cycle analysis)

1. Right-click the Engine node and select Create Cylinder and Valves.

   Within the Engine Parts Creation dialog, in the Engine Configuration group-box, Simcenter STAR-CCM+ In-cylinder displays the auto-calculated number of Intake Valve(s) and Exhaust Valve(s) of the imported engine geometry, respectively.

2. To set the cycle length, in the Engine Configuration group-box, set Strokes as follows:
   • 2: Sets a cycle length of 360 deg.
   • 4: Sets a cycle length of 720 deg.
3. In the Part Creation Options group-box, set Keep features edges (deg) to suit your geometry. Simcenter STAR-CCM+ In-cylinder creates part curves on named edges whose attached faces form an angle that is sharper than the specified value.
4. If the engine geometry allows you to use symmetry conditions, you can include only half the geometry, thus reducing the cell count and computational cost of the simulation:
   1. In the Engine Symmetry group-box, activate Half Model.
   2. For Symmetry Plane, select the side of the geometry to keep.

   For more information, see Engine Reference—Engine Parts Creation Dialog .

5. Click OK.
6. Depending on the imported CAD bodies, Simcenter STAR-CCM+ In-cylinder creates the corresponding Engine Parts:
   • Cylinder
   • Intake Valve [n]
   • Exhaust Valve [n]
   • Plenum [n]

   The Graphics window updates to display the Engine Parts (in pale blue color). For a half model, Simcenter STAR-CCM+ In-cylinder automatically applies symmetry conditions at the symmetry plane.

   注

   If the bodies, faces, or edges of your imported geometry are not named as described in Geometry Requirements, Simcenter STAR-CCM+ In-cylinder fails to create the Engine Parts. In the object tree, a red error icon indicates a failed Engine Part. Additionally, a message in the output window points you to the source of the problem. To rename bodies, faces, or edges after the import of the geometry, see Renaming Bodies, Faces, and Edges of the Imported Geometry.

7. If the Liquid Film engine model is selected, to model the formation and transport of liquid film on the engine walls, Simcenter STAR-CCM+ In-cylinder creates a shell region from all Engine Part Surfaces (visible only in the Simcenter STAR-CCM+ object tree).

   To improve the simulation performance, exclude Engine Part Surfaces where no fluid film is expected from the shell region:

   1. Right-click the Models > Liquid Film node and select Edit.
   2. In the Edit dialog, next to Liquid Film Surfaces, click Select....
   3. In the Select Objects dialog, de-select the Engine Parts Surfaces that you want to exclude from the shell region and click OK.
   4. Click Apply, then Close.

The created Engine Parts allow you to set the physics for the cylinder and the valves:

For a charge motion simulation, you create an additional Engine Part for the fuel injector:

To initiate the combustion process in a combustion simulation, you create an ignitor Engine Part:

(for closed-cycle analysis)

1. Right-click the Engine node and select Create Sector Model.
2. In the Create Sector Model dialog, set Number of Sectors to a value that results in a wedge angle which maintains reasonable cell apect ratios in planes perpendicular to the symmetry axis.

   Typically, the number of sectors is determined by the number of nozzles in the centrally placed fuel injector. As a cylinder sector must contain only one injector nozzle, the number of sectors equals the number of nozzles.

   The minimum number of sectors is 3.

3. Click OK.

   Simcenter STAR-CCM+ In-cylinder creates the Cylinder Sector Engine Part and applies periodic conditions at the side surfaces of the sector geometry.

   The Graphics window updates to display the Engine Part (in pale blue color).

4. If the Liquid Film engine model is selected, to model the formation and transport of liquid film on the engine walls, Simcenter STAR-CCM+ In-cylinder creates a shell region from all Engine Part Surfaces (visible only in the Simcenter STAR-CCM+ object tree).

   To improve the simulation performance, exclude Engine Part Surfaces where no fluid film is expected from the shell region as described in Step 7 for CAD geometries.

The created Engine Parts allow you to set the physics for the cylinder:

For fuel injection, you create an additional Engine Part for the fuel injector:

For a combustion simulation, the combustible mixture in the cylinder sector ignites spontaneously without an external source of ignition (auto-ignition).