[armani]

Hi everyone,

Regarding my project, I have to simulate laminar flow in drain pipe and movement of solid particles should be tracked! My problem is that these particles are not mixed in water, and they should remain at rest, before the flow comes through inlet. Actually I have to find the minimum necessary velocity, that is required to move these solid particles through the pipe for avoiding sediments.
I tried to use DPM model in Ansys Fluent 19. But the main problem is that I cannot define an inlet for these solid particles! I do not know how I can add them right after the flow inlet in my simulation!
Is there any way to make the simulation understand, that the solid particles are in pipe before flow comes? I also tried to define a section for injection of these particles, but it did not work.
I'll be thankful for any advice and help!

Thank you in advance!

Arman

[bhargavbharathan]

Hi,

1. Can you elaborate on what you mean when you say:

My problem is that these particles are not mixed in water, and they should remain at rest, before the flow comes through inlet.

Is there any way to make the simulation understand, that the solid particles are in pipe before flow comes?

Do you want your solid particles to be at rest and the flow of water to carry it away. Something like a river flowing over sand on the riverbed?

2. Try to split your simulation in to 2 parts. First run only the fluid and get a steady state solution for the flow equation. Then inject the solid particles.

I tried to use DPM model in Ansys Fluent 19. But the main problem is that I cannot define an inlet for these solid particles!

When you set your injection under discrete phase, you will be able to set it's inlet conditions, velocity, surface and type of injection etc.

-BB

[armani]

Hey!
Thanks for your help! The example of the river is exaclty what I whant to do!
I tried to define injection conditions but it did not wored! I also have to say because of the size of my particles which are too bigger than my mesh size, I changed the method to MPM!
Then I tried to run my simulation but Ansys crashed and it did not slove anything! I tried it seceral times with transient, but it could do the sinulation and when it tried to add prticle to may domain it crashed again!
I cannt understand where the problem is! When there is no praticle, it will work fine and the simulation is valid and correct! But whenever it comes to particle, no get through! I am really helpless and hopless with this simulation! I need the animiation of moving particles but i cant even inject them in may domain!

Do you have any idea?

Best regardd,

Arman

[bhargavbharathan]

Hi,

1. Draw two zones in your model. The bottom zone will later be your solid particles. Give it the thickness of riverbed.

2. Your model is similar to the fluidized bed tutorial that Fluent puts out.
The tutorial can be found at:
http://www.engr.uconn.edu/~barbertj/...2012/tut23.pdf

A good and educative video can be found on youtube:
https://www.youtube.com/watch?v=nwnB...&frags=pl%2Cwn

3. The thing to note in the above examples is, they use a multiphase-eulerian-granular model with no discrete phase and hence no injections. After initialization, they patch the solid phase to the zone created earlier.

4. You must have a PSD, but you can't set it unless you have a discrete phase and injections. You can try to follow the setup described for fluidized bed but with injections and see how it goes.


Good luck,

-BB

[Erasmus]

Originally Posted by armani

Hey!
Thanks for your help! The example of the river is exaclty what I whant to do!
I tried to define injection conditions but it did not wored! I also have to say because of the size of my particles which are too bigger than my mesh size, I changed the method to MPM!
Then I tried to run my simulation but Ansys crashed and it did not slove anything! I tried it seceral times with transient, but it could do the sinulation and when it tried to add prticle to may domain it crashed again!
I cannt understand where the problem is! When there is no praticle, it will work fine and the simulation is valid and correct! But whenever it comes to particle, no get through! I am really helpless and hopless with this simulation! I need the animiation of moving particles but i cant even inject them in may domain!

Do you have any idea?

Best regardd,

Arman

About using MPM model of Ansys FLuent i can give you some advices: i found this video very helpful:
https://www.youtube.com/watch?v=920ajl_nV68
https://www.youtube.com/watch?v=bGU62t9DDy0
let me know if you understand, i hope so


Good Luck
ED