Setting the Operating Conditions

Here, you set the conditions under which the engine operates. For a combustion simulation, Simcenter STAR-CCM+ In-cylinder applies Automatic Composition Initialization, by default.

Automatic Composition Initialization provides an automated approach for defining the exhaust gas composition and for setting the initial gas composition in the cylinder, the ports, and the plenums. The same automated approach is used for setting the gas composition at the flow boundaries. Alternatively, you can use verified engine data to set up the gas composition manually.
To set the operating conditions:
  1. Right-click the Operating Conditions node and select Edit.
  2. In the Operating Conditions group-box, set the following properties:
    • RPM
    • Start Angle
    • Duration
    • Reference Pressure
    • Default Wall Temperature
    • Constant Absolute Pressure Cylinder (only for cylinder sector models)

    See Operating Conditions Reference—Operating Conditions.

  3. For a combustion simulation, set up the gas composition in the engine using one of the following methods:
    MethodProcedure
    Automatic Composition Initialization
    1. Ensure that Automatic Composition Initialization is activated.
    2. In the Equivalence Ratio for Initialization group-box, set the following properties:
      • Definition
      • Initialization of Exhaust Gas Composition for All Parts.
      • Initialization of Unburnt Fuel/Air Mixture for Cylinder, Intake, Exhaust, and Plenum [n].
    3. For exhaust gas recirculation (EGR), in the EGR group-box, set the EGR definition according to company practice.
    4. Set the EGR percentage for Cylinder, Intake, Exhaust, and Plenum [n].
    5. Click Apply, then Close.

    For more information, see Operating Conditions Reference—Automatic Composition Initialization.
    Manual
    1. Deactivate Automatic Composition Initialization.
    2. Click Apply, then Close.
    3. Set up the Gas Composition Using Verified Engine Data.