## Fluids

Topics relate to Fluent, CFX, Turbogrid and more

#### Moving particle in a flow

• AliMosayyebi
Subscriber

Hello everyone,

I am using Ansys Workbench 2019 R2 and I was hoping to simulate the movement of different size/shape particles in a custom made fluid channel.

Perhaps a 2D would be a start?

I have capability to draw both particle and the channel using Autodesk Inventor Pro 2020.

Could you please help me understand how I can do it in ansys and what I need to do in 2D and then 3D?

Kindest,

Ali

• DrAmine
Ansys Employee

So you want to have a large particle with non-spherical shape?

• AliMosayyebi
Subscriber

Thanks for reply, I have tried to use MPM but does not seem to be working very well here. in 3D it works only in limited situaitons with small dimentions. as soon as I move onto a more realistic size, it causes my computer crash. I dont mind starting with spherical shape, initially. However the ultimate goal is doing it on any customised shapes with customised dimentions.

• Rob
Ansys Employee

More details on the crash will help: we may be able to offer advice on that.

The alternative is to review the 6DOF solver in Fluent and model the particle moving using that. The calculation will be much longer, but as you've not explained why you're doing the model I've no idea if it's necessary.

• AliMosayyebi
Subscriber

thanks for getting back to me. So, perhaps the best way I can explain it is by saying that I am hoping to simulation the movement of little particles with density of 2.5 g/cm3 and the diameter of about 500 micro-meter in a cavity of about 10cm X 13cm X 2cm (Width X Height X Depth). There are some internal channels with diameter of 2 cm inside this cavity.

I am hoping to simulate the traveling process of these particles through these channels and inside the cavity.

Hope this gives a bit of an idea about what I have in mind?

• Rob
Ansys Employee

Your options are then DPM, MPM or model the particle using 6DOF (moving mesh). That's in order of complexity and computational cost.  Have a look through the manuals to understand the options & their limitations then explain why you would/would not use each one.

• AliMosayyebi
Subscriber

Hello,

I have looked into all these options but couldn't find the result I am looking for, unfortunately. Do you know of any sample I can look into, please? I have tried to draw a sample of my shapes for your reference. I can send some CAD drawings if helps, too?

This is a laminar flow region while diameters of channels are about 10mm; Inlet flow rate is 0.1ml/min. Pressure outlet is 0.

• Rob
Ansys Employee

So, the channel is 10mm and the particle is 0.1mm   DPM should work OK depending on the cell size used.  How non-spherical are the particles?

• AliMosayyebi
Subscriber

Correct. currently dont mind using a completely circular. However, the ultimate goal will be doing them in 3D and uploading a customized shapes that wont be spherical.

The other element to perhaps consider, would be having the particle in the middle of the channel in 3D while in this initial case we have everything in 2D in which the particle is obviously not floating. This is hopefully going to show a cross-sectional view, maybe?

happy new year!

• Rob
Ansys Employee

If the particle is neutrally buoyant then 2d will be a good approximation of 3d. If it's not you'll find the upper/lower wall effects will become very important for particle motion.

• AliMosayyebi
Subscriber

Hi, the particle is not neutrally buoyant and we will have different particles with various densities and shapes. For now I am hoping to run simulation for one particle but then I will be looking to move to a more realistic situaiton. with this in mind, is there any done sample similar to what I have explaied here and above you can share with me to try, please? your help will be highly appreciated.

• Rob
Ansys Employee

I've seen large objects (pigs) pushed through domains. However, you need moving mesh and several UDFs to do this. How non-spherical are the particles?