Generation of user-defined object types is a powerful tool. These objects can be defined by combining the existing object shapes. Once defined, they can be used in GrainGeo in addition to the predefined object shapes, and new 3D structures can be created consisting of those shapes.

In this tutorial, we showed how to model a packed bed reactor with perforated cylinders.

Be aware that in the example presented here, the selected resolution is very low. This allows for a smooth and quick execution of the tutorial. The low resolution has a limited effect on the computed pressure drop results. However, the resolution is not sufficient to model the flow through the perforated cylinders precisely. For example, with AddiDict, the movement of particles or reactants in the fluid could be simulated. Such a more advanced analysis would require a higher resolution of the model.

So in general, we recommend to use a higher resolution for the piling process and the subsequent flow computations to achieve more accurate results.

However, a lower resolution is a good starting point to find appropriate parameters for the piling process and the subsequent flow simulation. The same holds for a model without all details (cylindrical catalysts), where the computational time in setting up the model is much faster compared to the model with all details (perforated catalysts).

Also note that the two structures we compared have more differences than only the topology of the catalysts. Due to the piling process, two different structures were generated, where the catalysts are positioned at different locations. Thus, the results of the flow simulation are not fully comparable.