Setting up the Reacting Channels

Reacting channel co-simulation is set up between the Plug Flow Reactor (PFR) in the reacting channels (where steam methane reforming reactions occur) and the firebox domain in Simcenter STAR-CCM+ (where combustion reactions occur).

Set up the reacting channels co-simulation:
  1. Right-click the External Links > Reacting Channel Co-Simulation > Values > Reacting Channel Chemistry Definition node and select Import Chemistry Definition (Chemkin format).
  2. In the Import Chemkin Files dialog, browse to and select the following files, then click OK.
    Chemical Mechanism File SpeciesList.dat
    Thermodynamic Properties File thermo30.dat
    Transport Properties File transport.dat
Set up the user coding to define the plug flow reactor (PFR) steam methane reforming reactions that occur in the reacting channels.
  1. To import the user coding:
    1. Right-click the Tools > User Code node and select New User Library.
    2. In the Open dialog, depending on the operating system that you use, browse to and select one of the following:
      • On Windows: user-code-Windows\libuser.dll
      • On Linux: user-code-Linux/libuser.so
    3. Click Open.
  2. To select the user coding for the reacting channels:
    1. Expand the External Links > Reacting Channel Co-Simulation > Values node.
    2. Select the Values > Reacting Channel Chemistry Definition > Reacting System Properties > Species Reaction Sources node and set Method to User-Defined.
    3. Select the Species Reaction Sources > User-Defined node and set User Function to wdot.
    4. Select the Reacting System Properties > User-Defined Species Sources Specification node and set Method to Calculate Species Sources.
    5. Select the User-Defined Species Sources Specification > Calculate Species Sources node and make sure that Internal Reaction Energy Source is activated.
Create two reacting channel zones—one to account for the pipes from which the reaction mixture flows out of, and another for pipes into which the reaction mixture re-enters.
  1. Right-click the Reacting Channel Co-Simulation > Zones node and select New.
Next, identify the boundaries that surround the reacting channels within the Firebox. These channels must be assigned to a zone and set to exchange data as part of the co-simulation.
  1. Expand the Regions > Firebox > Boundaries node then:
    1. Multi-select the FullFurnace.Pipe 1, FullFurnace.Pipe 3, and FullFurnace.Pipe 5 nodes. Right-click one of the selected nodes and select Edit.
    2. Expand Physics Conditions > External Code Coupling Specification and set External Code Coupling Specification to Reacting Channel Co-Simulation: Zone 1.
    3. Multi-select the FullFurnace.Pipe 2, FullFurnace.Pipe 4, and FullFurnace.Pipe 6 nodes. Right-click one of the selected nodes and select Edit.
    4. Expand Physics Conditions > External Code Coupling Specification and set External Code Coupling Specification to Reacting Channel Co-Simulation: Zone 2.
    5. Click Close.
    The External Links > Reacting Channel Co-Simulation > Zones > Zone # > Conditions > Coupled Model Parts node updates to show the boundaries that are selected in Simcenter STAR-CCM+ for coupling to the Plug Flow Reactor.
  2. Select the Zone 2 > Conditions > Reacting Channel Inlet Type node and set Inlet Type to Re-entry.
  3. Select the Zone 1 > Conditions > Reacting Channel Type node and set Correlation Type to Packed Bed.
    The reacting channels are specified as a packed bed reaction system. This setting signifies that each of the tubular channels is packed with porous material or particles—representing the catalyst—through which the methane steam reforming reaction components flow.
To create a realistic set-up for modeling reacting channels, it is important to set the properties of each zone to reflect the actual parameters and physics of the reacting channel tubes within the firebox. In this tutorial, the inlet area and pipe length values are taken from the dimensions of the geometry that is provided in the starting file. Other conditions and values are arbitrary or are based on values used by G.D. Stefanidis and others in [989]. To determine values that are realistic for a given case, you can calculate some of the correlation values using Simcenter STAR-CCM+. The wall orientation is set as the direction of flow within the reacting channel.
  1. Expand the Zone 1 > Values node and set the following Properties:
    Node Property Setting
    Area Value 0.00785 m^2
    Inlet Mass Fractions Inlet Mass Fraction CH4: 0.2851
    H2O: 0.7128
    CO2: 1.1403E-3
    N2: 9.597E-4
    Inlet Pressure Value 2797999.0 Pa
    Inlet Temperature Value 857.0 K
    Inlet Velocity Value 0.6 m/s
    Packed Bed Heat Transfer Factor Value 1.68
    Packed Bed Particle Diameter Value 0.0075 m
    Pipe Length Value 6.5 m
    Wall Discretization Value 0.065 m
    Wall Orientation Orientation [0.0, 1.0, 0.0]
  2. Expand the Zone 2 > Values node and set the following Properties:
    Node Property Setting
    Pipe Length Value 6.5 m
    Re-Entry Boundaries
    FullFurnace.Pipe2 Outlet Boundary FullFurnace.Pipe1
    FullFurnace.Pipe4 Outlet Boundary FullFurnace.Pipe3
    FullFurnace.Pipe6 Outlet Boundary FullFurnace.Pipe5
    Wall Orientation Orientation [0.0, -1.0, 0.0]
  3. Save the simulation.