Setting Boundary Conditions and Values

Specify boundary conditions for the inlet and outlet boundaries.

The boundaries symmetry plane, symmetry plane-2, and symmetry plane-3 are set to Symmetry Plane for this problem. The boundary Default Boundary Region is set to a reactive wall and boundary conditions for surface species are specified. Also, boundary conditions for the inlet and outlet are specified. For the outlet, the backflow conditions are provided, which are identical to the initial conditions that are specified above. For the inlet, a slightly faster velocity field is specified.

  1. Expand the Regions > Default_Fluid > Boundaries > pressure node.
  2. Set the following properties:
    Node Property Setting
    Physics Values
    Species Mass Fraction Value

    CH4: 0.02

    N2: 0.752

    O2: 0.228

  3. Select the inlet node and set the following properties:
    Node Property Setting
    Physics Values
    Velocity Magnitude Value 5.0 m/s
    Static Temperature Value 600 K
    Species Mass Fraction Value

    CH4: 0.02

    N2: 0.752

    O2: 0.228

  4. Expand the Boundaries > Default_Boundary_Region node and set the following properties:
    Node Property Setting
    Physics Conditions
    Surface Mechanism Option Mechanism CATALYST
    Thermal Specification Condition Temperature
    Physics Values
    Surface Initial Bulk Activity Profiles > BULKPT_BULK Activity Value Pt(B): 1.0
    Surface Initial Site Fraction Profiles > SITEPT_SURFACE Fraction Value Pt(S): 1.0
    Static Temperature Value 1000 K

    The Boundaries > Default_Boundary_Region > Physics Values > Surface Washcoat Factor node has a Value of 1.0 by default. This setting specifies that the boundary has a smooth surface.

Specification of the boundary conditions is now complete.

  1. Save the simulation.