About scale_reduction_rate

[mostanad]

Hi Developers,
I am just wondering what scale_reduction_rate really means here in your fix_chem__shrink_core model, here.
Is this something you specify to calibrate the reduction rate compatible with the experiments? I guess it generates some non-physical results for reduction time if you set it not equal to 1!

[danielque]

scale_reduction_rate simply scales the mass change for each layer in each time step by the given factor. We typically use it to quickly get an idea of reaction behavior that would take hours otherwise (which is a time span you usually try to avoid for large particle numbers). At the end of the simulation you need to scale back your reaction time to get the correct duration and of course the species consumption/production on the CFD side will be kinda messed up ...
For calibration of the model we rather look at properties such as porosity, tortuosity, and pore diameter as these really differ depending on the actually used material. To some extent you may also tune the activation energy and frequency factor k0.

[mostanad]

Well, thanks Daniel for your great explanation. I was just wondering why in all the test cases—both in CFDEM-coupling and LIGGGHTS—the scale_reduction_rate has a value other than 1. I initially thought it might be a physical parameter and that I had simply missed it in my understanding of the three-layer USCM.

Now, based on your explanation, it seems that this parameter physically scales the reduction in particles but can mess up the gas composition, which makes more sense. It was a bit confusing to me, especially since there isn’t much description about it in the doc.

By the way, is the three-layer USCM implementation in the package validated?