Setting Boundary Conditions and Values

Boundary conditions need to be specified at the two inlets as well as the pressure boundary. We will start with the inner (methane) inlet.

Select the Regions > Fluid > Boundaries > Inner_inlet > Physics Values > Mass Fraction > Constant node.

Set the Value property to [0.0, 1.0]

Select the Static Temperature > Constant node.

Change the Value property to 323 K.

Select the Turbulence Intensity > Constant node.

In the Properties window, change the Value property to 0.1

Similarly, change the Turbulent Viscosity Ratio to 100 and the Velocity Magnitude to 10 m/s

Now define conditions at the air inlet.

Open the Outer_inlet and Physics Values nodes and set the following properties as shown below:

Mass Fraction = [1.0, 0.0

Static Temperature = 293 K

Turbulence Intensity = 0.1

Turbulent Viscosity Ratio = 40

Velocity Magnitude = 5 m/s

Similar properties must be assigned to the pressure boundary. These are only used at locations where inflow occurs.

Open the pressure and Physics Values nodes and set the following properties as shown below:

Mass Fraction = [1.0, 0.0]

Static Temperature = 308 K

Turbulence Intensity = 0.1

Turbulent Viscosity Ratio = 40

The default Static Pressure value is suitable for this tutorial and therefore does not need changing.

This completes the specification of boundary conditions and values.

Save the simulation.