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-   -   Rotating blades of a fan by Fluent? (http://www.cfd-online.com/Forums/fluent/132011-rotating-blades-fan-fluent.html)

guillaume1990 March 24, 2014 09:48

Rotating blades of a fan by Fluent?
 
1 Attachment(s)
Hello !

First of all, is it possible to do the simulation of a fan? If yes, is there a tutorial please?

I would like to study the impact of air flow on the blades of a fan. So I modeled the fan as follows (see file). I put as a boundary condition: wall1 for the duct wall2 for the hub wall3 for blades with its support. I added to the input and the output a surface(not shown in the figures) for pressure_inlet and pressure_outlet. But in the study, how can I rotate the blades? Is it possible with Fluent?
Is there a tutorial for the simulation of a fan?

Any suggestion would be great !

Brendan March 24, 2014 12:29

reply
 
hi, not sure how you applied your boundary conditions since I cannot see your fluid domain. Have you got a screenshot of your mesh and boundary conditions applied?

guillaume1990 March 24, 2014 12:47

5 Attachment(s)
Hi ! Thank you very much for your answer.
So, I join the files with boundary conditions. I hope it's better.
For inlet and outlet of the pipe, I applied a section and I have done an extrusion of 1 mm. So these sections are connected to the wall. Indeed, I am not sure that is the right way ...

Brendan March 24, 2014 14:23

Geometry
 
Ok I see what you have done, unfortunately to my understanding you have modelled the opposite of what you should have. You want mesh only where the fluid is, not its surroundings. This is a typically setup for a program like solidworks flow simulator!!!
You should check out a few videos online about meshing with ICEM. It's the best way to explain the best approach!
Good luck with it!

Bionico March 25, 2014 04:22

Hello,
I suggest reading Fluent Manuals about Moving Reference Frame (above all Tutorial Manual). Sliding Mesh Model could also be useful, it depends on the study you want to do.

Regards

guillaume1990 March 25, 2014 04:32

Thanks you. So it's not possible to do the simulation of a fan if I don't have the software ICEM? :(
Because I have only Workbench with Fluent, Meshing, Design Modeler..

Edit: however, maybe I can have the software ICEM. But Solidworks Flow Simulator is not possible. So, with just Fluent and Icem, is it possible? Thanks

Bionico March 25, 2014 04:43

Once I have simulated a cross-flow fan using Workbench (Design Modeler + Meshing) and Fluent with Moving Reference Frame. I think that ICEM is one of the best Meshing Software but you can settle for Basic Meshing.

Regards

guillaume1990 March 25, 2014 04:46

Thanks Bionico.

I know Moving Reference Frame, I will use it in the configuration of Fluent to rotate the blades of the fan.

Nevertheless, I don't know Sliding Mesh Model. It allows to mesh the fluid as Brendan suggests? If Yes, is it possible with what software? Just Meshing? Or Icem?

For the study, I want to study the impact of an air flow on the blades of a fan. Theses blades rotate.

Edit: Oh ok, it's great you succeeded to do the simulation of a fan. Could you tell me how have you done to mesh only the fluid and the blades? Because it seems that my pictures are wrong. Thanks

Bionico March 25, 2014 06:32

Sliding mesh model is a more complicated model to simulate moving parts: Fluent Manuals explains very well the differences between this and MRF model. I think that your mesh is suitable (of course you have to check discretization parameters like Y+): the choice between ICEM or Basic Meshing in WB depends on how you want to refine your mesh (ICEM offers a more manual control on the mesh, but it's more complicated).

Regards

guillaume1990 March 25, 2014 08:36

Thanks.
Before improving the meshing, I just want that the blades rotate so that I can study the impact of an airflow. So, I don't check the meshing. I just want that the simulation works. I will verify the meshing in a second time.

I have done the meshing as shown on the pictures but I can't select the blades in fluent to apply the moving frame reference. Is there a link where I can see how I have to do to rotate the blades and apply the boundary conditions for inlet and outlet?

Brendan March 25, 2014 09:04

Icem
 
For reference, icem is the meshing software embedded within ansys workbench. You are already using it!!!
The actual domains you have are not correct, the first thing you need to do if you plan on using fluent, check out "boolean" subtract for geometry to make it work!!! You need two domains, stator and rotor separated by an interface boundary.
Takes time and YouTube is a great help.

guillaume1990 March 25, 2014 09:11

Thank you very much :)

But I don't understand very well.

"check out "boolean" subtract for geometry to make it work!!!"

What do you mean?


You need two domains, stator and rotor separated by an interface boundary.
How can I do?

I have done some research to find some tutorial but I don't find. I am not very good in English so maybe I don't put the right keywords in Youtube for exemple. If it's quick for you, could you suggest me a youtube link? If it takes time to find a link, I understand completely. Thank you anyway :)

Brendan March 25, 2014 09:49

boolean
 
Ok, "Boolean Subtraction" is a method whereby the geometry of the actual 3D modelled blade can be subtracted (i.e. 1 from 1) from a "non-merged" extruded body which encloses the entire blade geometry. Therefore you are left with a extruded cylinder with a "cavity" inside it of the blade geometry. This will be your rotating region (rotor).
This new geometry part must be placed inside a separate extruded box or cylinder and this will be your "stator".
Therefore you will have all "solid" bodies except for the cavity which is the blade geometry.
This means you can set all the solid regions, both stator and rotor to "fluid" and the mesh can be carried out on the entire setup.
I will check for a video on youtube and post as soon as possible.
P.s this setup will require a relatively capable pc, i.e cpu and ram!.

guillaume1990 March 25, 2014 10:34

Thank you again for your time.
I understand better now I have to separate the domains. I am going to try.
If you find a video, that's great ! Otherwise, that's okay, I don't want you take too much time for searching.

guillaume1990 March 27, 2014 04:19

By any chance, did you find a video or something else? Otherwise thanks anyway :)

vatsal1610 June 30, 2014 10:59

@guillaume: May I know what kind of interface have you used in Fluent because I am not able to achieved my desired results and I am using 'Coupled Interface'.

guillaume1990 July 1, 2014 08:51

http://www.cfd-online.com/Forums/flu...lades-mrf.html

Here is the post which have been very useful for my part. I didn't use interfaces.

Good Luck !


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