Volume fraction of dispersed phase to determine DPM, VOF, Mixture model
 

Hello

For using DPM model in fluent, volume fraction of disperesed phase should be below 10% to 12 %, otherwise you have to look for other models such as mixture and VOF models in fluent.

For determining Volume fraction of a particle, the following formula is used:

alpha=NpVp/Vc

where alpha= volume fraction of solid phase
Np=Number of particles
Vp=Volume of particle
Vc= Volume of the container or total volume of the cylinder or the whole control volume.

If alpha comes out to be greater than 12% then "mixture" or "VOF model" would be considered for dense phase.

Please comment if the above statements are correct/wrong.

Thank you so much.
Mohsin

Hi,
The whole idea is right but some other points should be noted:
- Actually this range is not very tight; it's just a rule of thumb, I believe that if Lagrangian modeling could be proper for a case we can use it.
- Note that DPM modeling in FLUENT encounter many bugs in brownian motion and computing deposition, so in many cases in which diffusion term is dominant in dispersion; such as nano-particles, we have to use eulerian modeling, i.e. solving a transport eq. to find particle concentration.

Amir

Well, Amir, thank you very much for the guidance. Added to ur reputation:)