Running the Simulation and Reviewing the Results

You can review the progress of the simulation as it runs by monitoring the scalar scenes and reports that are set up.

Before running the simulation, define the solver settings and stopping criteria:
  1. Select the Solvers > Segregated Flow node and activate Continuity Initialization.
  2. Expand the Solvers > DO Radiation node and set the following:
    Node Property Setting
    DO Radiation Maximum Iteration 25
    Solver Tolerance 0.001
    Update Frequency
    Steady Iteration Update Frequency 10
  3. Run the simulation .
Running the case can take a considerable time—depending on the number of processors that are being used. Using four processors can take several hours.
  1. When the maximum number of steps is reached, save the simulation .
  2. In the Output window, click the Temperature tab.
    The scene displays the temperature on an arbitrary plane surface through the centre of the furnace volume and on the surface of the reacting channels. You can see that the temperature along the length of the channels is distributed evenly as expected. An even temperature distribution ensures that the reaction components within the channels are exposed to a consistent temperature within the full length of the channels.

  3. In the Output window, click the Heat Flux tab.
    The heat flux is displayed along the external surface of the reacting channels. The heat flux is highest at the initial entry points to reacting channels one, three, and five—where the endothermic reactions are starting to occur and take in heat from the surrounding firebox.

  4. In the Output window, click the Mass Fraction of CO2 at Outlet tab.
    The mass fraction of CO2 at the Outlet reaches a constant value of around 0.13.

  5. In the Output window, click the Temperature at Outlet tab.
    The temperature at the outlet reaches a constant temperature of around 1350 K.

  6. In the Output window, click the Reacting Channel Temperature tab.
    The temperature increases along the length of the reacting channels to above 1500 K at the end of the pipes. In this simulation, long thin cylinders, which are not tapered at the end, represent the reacting channel pipes. If the pipes were tapered at the end, the temperature at the end of the pipes is more likely to stabilize or drop slightly.

  7. In the Output window, click the Reacting Channel Heat Flux tab.
    The negative heat flux values show that heat is travelling into the reacting channels—as expected, from the firebox. Nearer the ends of pipes two, four, and six, there is close to zero heat flux. At that point, the endothermic reactions—that take in heat from the surroundings—are nearing completion.


  8. In the Output window, click the CH4 Mass Fraction tab.
    The mass fraction of CH4 drops along the length of the reacting channel tubes as the reactions within the channels consume CH4.

  9. In the Output window, click the H2 Mass Fraction tab.
    The mass fraction of H2 increases along the length of the reacting channel tubes as the reactions within the channels produce H2.