Using Tracers in a Barracuda Virtual Reactor Model

Shane Lanzon_20859

Tracers can be used to track fluid flow and fluid residence time in a simulation. Tracers are Lagrangian entities that do not have any mass or volume, and they follow the fluid flow path. They can be injected at a Pressure, Flow, or Injection BC, and they can pass through BC Connectors in order to fully follow the fluid flow through a model. For more information, see the Tracers section of the User Manual. 

 

To add tracers to your boundary conditions, navigate to the Tracers tab, and select Tracer feed. You can specify a species number, which starts at 2000 in order to not overlap with any other particle or bubble species created in the simulation. A tracer resolution must be specified which determines how many tracers per second are injected at the boundary condition.

 

To visualize tracers in Tecplot for Barracuda, use the Tracers: Residence Time macro in the Quick Macro Panel. Depending on the tracer resolution, the tracer shape and size may need to be adjusted (see instructions on how to do this starting at 03:54 in this video).

 

In order to create a histogram of fluid residence time, select Output tracer data at the fluid exit flux plane(s). This will output a <flux plane name>_raw_tracer file that can be analyzed with the attached Jupyter notebook. It is necessary to have Python installed in order to perform this analysis. For instructions on how to start a Jupyter notebook, see this video starting at 02:39.

 

The notebook contains two examples using the Gasifier training example included in the Barracuda Virtual Reactor New User Training, which has been modified to feed tracers at the bottom-most flow BC in the model. The first example in the notebook creates a histogram of tracer residence time with one flux plane input, and the second creates a histogram with four flux plane inputs. The second example can be adjusted to any multiple of inputs in order to get an additive histogram, by adding more flux plane names to the list.

 

You will need to specify the fluxPlaneName and resTimeCol values that apply to your simulation. The numBins can be adjusted to increase or decrease the resolution of the residence time peak of your data. 

 

The resulting plot shows a histogram of the fluid residence time distribution with the peak at approximately 12 seconds.

 

The second example has a fileList that you can use to specify any number of file names. The data in the files will be appended, so be sure that it makes sense to add all the files at once in your situation. For the Gasifier example, the four flux planes correspond to the four cyclone pressure BCs, which are the only outlets for the system, so it makes sense to add these together to get a total tracer residence time distribution for the system.