## Fluids

Topics relate to Fluent, CFX, Turbogrid and more

#### Model particle transport and depostion in a long capillary with very small radiu

• Fluent User
Subscriber

Dear all,
I hope you can help me.
I am simulating a horizontal capillary (d= 0.8 mm and L= 1m) in which the water shall be filtered and the transport and deposition of particles shall take place.

The water enters the system from the right and gets out from the whole capillary body (membrane wall). The other end of the capillary is fixed (no water can pass through).
I tried to model half of the capillary, but I couldn't fix the capillary centre axis line (boundary condition).

Now I am trying t have 3-zones: the middle one is the space where the water will flow, and the upper and the down one are porous zones.

Is that correct?
Do you have any suggestions?

Best wishes

I am simulating half of the capillary

• Rob
Ansys Employee

What are you trying to find out? Which model are you going to use for the particles?

• Fluent User
Subscriber

Thank you for responding.

I am trying to model the particle transport and deposition in order to see the formation of the cake layer inside the capillary.

I will be using Euler-Lagrange.

Best wishes

• Rob
Ansys Employee

The DPM model won't show a cake forming. Eulerian will just about, but you may want to look at Ansys Rocky.

Scale may be an issue depending on how big the particles are relative to the channel and mesh.

• Fluent User
Subscriber

As far as I know, Rocky is for a dense system, right? My system is not dense.
The particles are of the size (0.001-45 µm)
The membrane pores are 0,013 µm ± 0,007 µm.

I have an equation to calculate the cake height during simulation by calculating it as a function of time and having it as an output of the simulation.

• Rob
Ansys Employee

The membrane pore size only matters for the porous coefficients. If you assume particles don't build up so you don't create a physical cake DPM should be OK. If you want the cake, DPM isn't suitable, but Rocky is.