Reporting, Monitoring and Plotting

STAR-CCM+ can dynamically monitor virtually any quantity while the solution develops. This requires setting up a report defining the quantity of interest and the parts of the region to be monitored. A monitor is then defined based on that report. The former also helps to create an appropriate X-Y graph plot.

Report monitors will be used in this case to compare the mass of carbon atoms flowing into the solution domain with the mass of such atoms flowing out of it. Once the two monitors reach the same value, it is reasonable to assume that the solution has converged also. To set up these reports, a field function that calculates the mass flow rate of carbon needs to be created. In view of the species involved in the 3-step reaction mechanism, this field function may be defined as follows:

where

is the mass flow rate of carbon,

the total mass flow rate and

and

the molecular weight, the atomic weight and the mass fraction of species X, respectively.

Open the Tools node, right-click the Field Functions node and select New.

Right-click the User Field Function 1 node and select Rename...

In the Rename dialog, change the field function node name to Carbon and then click OK

In the Properties window, change the Function Name property to Carbon also.

Click the customizer box for the Definition property and enter the code shown below in the Carbon - Definition dialog.

Click OK.

The value of the Carbon field function will be positive over outflow boundaries and negative over inflow boundaries. Therefore, to make a side-by-side comparison of carbon inflow and outflow, we need to create another field function for the inflow boundaries that is the negative of the one created above.

As before, right-click on the Field Functions node and select New.

Following the same procedure, change both the node name and function name of the new field function to MinusCarbon and enter its definition as 0-$Carbon

Right-click the Reports node and select New Report > Sum to create a report node named Sum 1.

Repeat the above process to create a report node named Sum 2.

Right-click the Sum 1 node and rename it Carbon In.

Similarly, rename the Sum 2 node as Carbon Out.

Select the Carbon In node and, in the Properties window, add the four inlet boundaries to the Parts list.

Select MinusCarbon for the Scalar property.

Similarly, edit the properties of the Carbon Out node so that the outlet boundary is the only item in the Parts list and the Scalar property is set to Carbon.

Right-click the Carbon In node and select Create Monitor and Plot from Report.

Right-click the Carbon Out node and select Create Monitor from Report.

No plot is created for the Carbon Out Monitor because it will be added to the Carbon In Plot so that the convergence of the two can be observed more easily.

Open the Plots and the Carbon In Plot nodes, then right-click the Monitors node and select Edit....

In the Customizer dialog, add Carbon Out Monitor to the Selected list and then click Close.

Rename the Carbon In Plot node as Carbon Balance.

Make sure that the Title property of the Carbon Balance node is Carbon Balance.

Double-click the Carbon Balance node to display the empty plot in the Graphics window.