Hi, everyone,

I want to model the slurry with at least three size of particles distributing in it. I want to know the separation process of the slurry under gravity sedimentation. Anyone know which software has such capability?

Thank you!

J.Yang

Hi,

CFX can do this kind of simulations.

Best regards

I think most software with an euler euler solver for multiphase flow should be able to do that. If I understand it correctly then it is just a matter of solving an additional similar equation for each size group. I standard answer to such a question in this forum is try to contact the different software vendors and ask them your question - look under the resources pages. Good luck

Hi, thank Alian and Jan for your helping. But CFX only can model two phase fluid. My problem is that I want to model the slurry with various sizes of dispersed solid particles distributing in continuous water. The solid particle size ranges from 0.2 micron to 2 mm. So I need model every particle group using one phase.

Thank you very much!

J.Yang

You still only have two phases - slurry and the particles! The number of size groups has nothing to do with a phase - they are still "a particle phase" You can then solve more equations for your dispersed phase representing each size group. Jan

IMO You should look for a program which solve the transport equations for particle/droplet groups (probably in a Lagrangian way). The particle size range is subdivided into appropriate classes and a transport equation for each particle group is solved.

I think using a multiphase approach is not appropriate for your problem and computational not feasible. If you have a lot of different particle size classes they should not be modelled as a continuum.

Dear Free_and SIMPLE I could be wrong on this, but then hopefully will be corrected.

The selection of how to model a system with a fluid and particles depends mainly on the load, how dense or diluted the dispersed phase is. For very high mass loading is the euler/euler prefered. The main problem with euler/euler and multiple size groups is that a transport equation has to be solved for each size group - so it depends on your hardware. But 3 or 4 size groups should not be a problem, that is at least what I have solved on my small PC. Maybe there also exist euler/euler codes that can handle a size distribution. Jan

Dear Jan,

of course you are correct. The model of choice depends on the load. The problem I see with Euler/Euler continuum treatments is the physical sound formulation. If you treat the size groups as scalar quantities with global interactions it will work, but if you are looking for a "real" multiphase model, where each group has its own velocity field you might run into troubles. An alternative can be a pdf approach which is very common in combustion and spray simulation.

Best Regards.

Hi,

As a matter of fact CFX has the capability of solving EULER/EULER multiphase with more than 2 phase :

In CFX 5 (unstructured) you can use pure euler/euler with up to 5 phase but there is no granular euler which you may need.

In CFX 4 (structured) an arbitrary number of phases may be specified. There is also a specific model MUSIG (Multiple-Size Group) which is available to represent the size distribution of a disperse phase.

There is certainly other software that can do this kind of simulation i think.

From theorical point of view I don't think that euler lagrange approach is suitable for sedimentation problem as this model suppose a finite residence time for particules.

Best regards

Alain