[Meca_Ali]

Dear Ansys Fluent users,

I am new to this software, so I need help regarding a continuous mixing flow simulation in a Tank.
This simulation will be needed to predict fluid velocity in each department of the tank as well as the direction of the flow, knowingly that the tank will be equipped with 8 mixers (1 mixer in the center on tank, 7 others by its shell, all mixer will rotate with the same velocity but not necessarily in the same direction of rotation) hers a snapshot of the 3D model.

I need to know mainly two things:

1- Can this simulation be elaborated in Ansys fluent,
2- How difficult is the simulation on scale of 1 to 10.

Thank you

[Gert-Jan]

- Yes it can be done in Fluent
- I would recommend CFX for this. Easier to setup rotating parts, provided it is single phase
- The difficulty depends on the details. So what question are you exactly trying to answer using CFD? Shaft power? Axial forces? Vibrations? Mixing? Heat transfer? Chemical Reaction? Residence time? Multiphase? Pseudo-plastic behavior?

[Meca_Ali]

Dear Gert Jan, thank you

I am looking to see residence time for the fluid as well as its volocity in each point, knowingly that it is introduced into the tank in the central mixer and then passing through the other 7 mixers,
The fluid have canstant viscosity and temerature, all the mixers have the same rotating speed but not the same rotation direction.

Could you give me some guidence on how to introduce the model please

[Gert-Jan]

I tend to perform all simulations with rotating parts in CFX. There I can help you. Not in Fluent.

But where to start? I would suggest to work through a few tutorials and come back in a couple of days.

[Meca_Ali]

Could you give me a few key words that can help me search for the right tutorials

[CeesH]

multiple reference frame, sliding mesh. Those are essentially the choices you have when it comes to modeling rotating equipment in FLUENT, and you'll have to choose between them. Complicated simulation? Not really. But considering the size of the stirrers compared to the domain, you'll need a pretty fine mesh. So be prepared to wait for quite a bit

[Meca_Ali]

Thank you CeesH

Could you please point me in the direction of a tutorial or expemple (video) of a simulation that is similar to my application,

Thank you

[CeesH]

https://www.youtube.com/watch?v=tC7EezDNkfE

This one gives a sliding mesh tutorial for a mixing tank. For multiple reference frame (less time taking, but also less accurate in the sense that it does not account for transient motion due to the impellers), simply change mesh motion to frame motion.

Also (bit older one) https://www.mr-cfd.com/mixing-tank-m...uent-software/

And this is a nice reference for an overview: http://www.bakker.org/dartmouth06/engs199/07-flow.pdf