[froniawi]

Hi all,

My problem is concerning a sphere in a closed box and a fluid (initially of species A) flowing in between them. Now, I would like the sphere to take up one species (A) and excrete another (B) in a way that the mass-fluxes scale by A_in:B_out=2:1.

As you can see, there is a difference in mass-flux. Theoretically, the difference in mass is taken up by the sphere, which would thus grow in mass and volume. This is not yet implemented, since: it is not essential to me (except, maybe for mass-balance) and I have no idea how to model it.

Could you please help me with these topics:
- Is mass-balance conserved in my actual situation? So, without the difference in mass taken up by the sphere. (In my opinion: No)
- If not, is there a way to model this? Solutions involving a static sphere as well as a growing sphere are welcome.

By the way. Cheating with the densities of the species is not possible, since this problem involves buoyancy.

Thanks in advance for reading and helping. It is greatly appreciated!

Best regards