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-   -   [ANSYS Meshing] Geometry and meshing of a static mixer (http://www.cfd-online.com/Forums/ansys-meshing/106466-geometry-meshing-static-mixer.html)

parradux August 29, 2012 13:10

Geometry and meshing of a static mixer
 
Hi,

I'm quite new to ANSYS and have just started to use the program. I have some questions regarding geometry setup and meshing.

I'm trying to simulate flow in a static mixer with helical elements.

In the design modeler I created the helical and I set it to function as a solid. I then created a cylinder that goes over the helical which I set to the fluid type. I then created a surface body that is the pipe of the static mixer. Does this sound right?

Each of the helicals is its own body (6 in total), along with the surface body and the fluid.

When I open up the meshing application (I just want to get a default mesh going for simplicity's sake) and when I get generate mesh I get a mesh that goes through everything. What I think I need is just a mesh on the fluid part that ends and connects to the surface of the helicals. The end objective is to simulate pressure drop using fluent.

My question is: is this the right approach for this objective? If not, what do I need to do to make it. Do I need to cut out the helical parts from the fluid part and if so how do I do that? And if not, how do I make the meshing work correctly?

diamondx August 29, 2012 23:44

Quote:

I then created a cylinder that goes over the helical which I set to the fluid type.
Did set that body to frozen ? then did a boolean operation on the bodies ?? can you post more pictures ?
please refer to this post :http://www.cfd-online.com/Forums/ans...tml#post346516
there is also a link to a video there, take a look at it. i hope it can help !

parradux August 29, 2012 23:50

All bodies were set as frozen.

After this was done I tried two things:

1) I did a boolean operation to subtract the bodies from the fluid to produce a fluid with helical shapes inside of it.

I then extruded a thin wall (thickness 0) around the fluid to serve as my surface body. I don't know if I need to do this or not.

2) The second thing I did was create the surface first, then I created 2 caps on each end of the mixer. I then filled the mixer to generate the fluid volume.

Both methods when I try to mesh have contact errors. In design modeler I don't see any red or missing connections so I don't know what gives.

I don't have access to my files right now. Can you tell me which method is better and if I am doing anything wrong whatsoever?

diamondx August 29, 2012 23:54

if you extrude a cylinder that goes through the helical shapes with frozen features, you don't need to create thin wall....try just that see what's the result

parradux August 30, 2012 00:17

Ok. Ive done that i believe. One last question when i setup thr meshing i namr my inlet and outlet as named selections then i generate the mesh. When i run fluent for a viscous laminar flow model im having a problem with only seeing solutions on the helical shape not the fluid even thoigh the helical shapes are not present since i removed them. How can view my flow domain on the fluid and not the helical shape?

diamondx August 30, 2012 08:25

When you do subtraction, you don't have to delete the body, you can just de-activate in ansys meshing. please take a look at this video:
http://www.youtube.com/watch?v=4wRCkh_qW3c

Or this one, i'm sure you can find a solution on one of these videos:

http://www.youtube.com/watch?v=bBa6Zp0cmzU

samidabest August 31, 2012 04:03

meshing problem
 
i draw the 2d model in the ansys when i did meshing on it, it show 3d figure.... so what i do...... help me

diamondx August 31, 2012 10:00

are you using ansys meshing or icem ?

samidabest September 1, 2012 09:23

i'm using ansys meshing

abdul Sami September 9, 2012 07:29

meshing problem
 
Hi every One!

i want to know that in ansys how i create thick mesh near the boundries and in the centre it should be thin plz help any one


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