I am using an *Euler-Euler* method to model two phases - both are treated as a continuum using modified *Navier-Stokes* equations. One phase is air and the other is particles, that are being entrained by the air.

The original geometry is very small, the airpath being 2 x 20 mm.

When the mesh is scaled up 10 times (grid fineness is **not** changed, the **dimensions** are, i.e. become 20 x 200 mm), the results match experimental ones pretty well. 

Grid independence has already been carried out. Irrespective, the scaling problem is seen in both coarse and fine grids. I am thinking along the lines - discrete phase is more accurately modelled with bigger dimenions.

It is a transient simulation, with atmospheric pressure at inlet and a pressure gradient at outlet. The computational domain resembles a 'T' shape, with powder at the bottom and airflow at the top.

Errors in experimental data are unlikely, as it is an established powder entrainment pattern.