Setting the Initial Conditions

You initialize the cylinder and the GAVs with methane gas at a pressure of 12 bar and a temperature of 1000 K. In the exhaust port, the methane gas has an initial pressure and temperature of 1.5 bar and 700 K, respectively. Finally, you initialize the intake port with air at a pressure of 2.5 bar and a temperature of 330 K.

By default, Simcenter STAR-CCM+ In-cylinder uses Automatic Composition Initialization to automatically determine the initial gas composition in the engine parts based on the fuel-air mixture and the exhaust gas recirculation (EGR) composition. To set the initial gas composition in the Engine Parts explicitly, you deactivate Automatic Composition Initialization.
To set the initial conditions:
  1. Deactivate Automatic Composition Initialization:
    1. Right-click the Operating Conditions node and select Edit.
    2. In the Edit dialog, deactivate Automatic Composition Initialization.
    3. Click Apply, then Close.
  2. Set initial conditions for the cylinder and the exhaus port:
    1. Right-click the Engine > Cylinder node and select Edit.
    2. Within the Edit dialog, in the Initial Conditions tab, click Cylinder.
    3. In the Cylinder group box, set the following properties:
      PropertyMethod

      Setting

      PressureConstant12.0 bar
      TemperatureConstant1000.0 K
      Air Mass Weighting-0.0
      Exhaust Mass Weighting-1.0
      Fuel Mass Weighting-0.0 (default)
    4. Click Cylinder to minimize the group box, then click Exhaust Port 1.
    5. In the Exhaust Port group box, set the following properties:
      PropertyMethod

      Setting

      Absolute Static PressureConstant1.5 bar
      TemperatureConstant700.0 K
      Air Mass Weighting-0.0
      Exhaust Mass Weighting-1.0
      Fuel Mass Weighting-0.0 (default)
    6. Click Apply, then Close.
  3. Set initial conditions for the GAVs and the intake port:
    1. Using the method as described in Step 2, set the following initial conditions for the GAV 1, GAV 2, and Intake Port Engine Parts:
      Engine PartPressureTemperatureAir Mass WeightingExhaust Mass WeightingFuel Mass Weighting
      GAVs > GAV 112.0 bar1000.0 K0.01.00.0 (default)
      GAVs > GAV 212.0 bar1000.0 K0.01.00.0 (default)
      Intake Port2.5 bar330.0 K1.0 (default)0.0 (default)0.0 (default)
  4. Save the simulation .