Wasp-Durand relative concentration (X) exceeds 0.8

A Caution message in AFT Impulse

Full Message Text

Wasp-Durand relative concentration (X) exceeds 0.8 and relative concentration for d95 particles (Y) exceeds 0.5 in pipe Z, indicating the slurry only consists of a pseudo-homogeneous component. However, the Liu Dezhong Model accounts for both pseudo-homogeneous and heterogeneous components.

Explanation

In quasi-homogeneous flow conditions, there are few solids in the heterogeneous slurry component with nearly all contributing to the homogeneous component. The heterogeneous gradient has little contribution to the overall pressure and flow results, but Wasp-Durand methods may still be appropriate for modeling the pseudo-homogeneous component.

Required Action

As the pseudo-homogeneous component is dictating results almost exclusively, modeling the homogeneous hydraulics accurately is more important than capturing heterogeneous effects in these pipes. Modeling the apparent viscosity appropriately is therefore of particular importance under these conditions.

If the entire system is quasi-homogeneous and the slurry is expected to exhibit non-Newtonian behavior, it may be better to model the system as a non-Newtonian fluid rather than as a settling slurry.

However, if rheological data is unavailable, use of the Wasp-Durand slurry model with Fei Xiangjun or Thomas viscosity models is likely to provide more accurate results than modeling the fluid as a pure Newtonian fluid.