Cell size Vs. particle size
 

Hi.

I'm working with an eulerian-eulerian model. One of my solid phases has a diameter of 0.004 cm. Should my cell have a size less than 0.004?

You didn't specify the relevant details of the problem. With that in mind, the cell size should generally be quite a bit larger than the particle size. If the particle is in the order of the cell size (or larger) the problem becomes one of DNS. If you think about, how would you account for forces and momentum balance if a particle spans over one or more cells?

Adrin