Solving Fick's second law of diffusion in 1D sphere using FiPy

I'm trying to solve the second law of diffusion for spheres PDE using fipy. I've checked the documentation but there's no example for such a case, so I was wondering if it is actually possible to do it, as I was not successful reaching for the adequate equation definition structure. I consider azimuthal and zenith angular symmetries, so the equation I need to solve results in the following.

Of course, boundary conditions are fixed at r=0 and r=R at fixed values and the initial concentration is also known. I also tried to follow the ideas presented in here but didn't get any clear result for it. Any ideas would be welcomed.

https://stackoverflow.com/questions/66164005/solving-ficks-second-law-of-diffusion-in-1d-sphere-using-fipy February 12, 2021 at 06:38AM