Learning Forum

[dungnguyenxuan199566]

Hi everyone,

Does anyone know how to make an inlet into this region?

I am trying to simulate human airway inhalation.

I am trying to make an inlet for this model but as you can see, the inlet is not normal shape and hard to select as inlet layer.

Besides, if you ever made human airway simulation, please share your workflow and experience. I really appreciate it.

[Essence]

Hello,

I would suggest you to please go through the Ansys tutorials:

/courses/index.php/courses/3d-bifurcating-artery-steady/

/courses/index.php/courses/fluent-3d-bifurcating-artery/

[dungnguyenxuan199566]

Hi Essence,

Thank you very much for the tutorials. However, in the links that you have posted, the authors skip the making inlet step. As you see, my object does not have a flat surface inlet as in the tutorials. I wonder if is there any way to add an object or add a surface there so that it will serve as an inlet area for my object

[dungnguyenxuan199566]

Thank you very much!

[Essence]

Hello,

The image you shared, is this the fluid domain? Did you extract the fluid domain successfully?

[dungnguyenxuan199566]

Hi,

No, not yet. What does it mean? and How can I do that?

[Essence]

You need to first extract the fluid domain in SCDM or Discovery and then mesh the fluid domain. Then this mesh needs to be imported to the Fluent solver. However, you can also extract the volume in Fluent mesher. I would recommend you to go through the AIC courses which demonstrate the same.

For more information, please refer the Ansys guide link:

https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v232/en/spaceclaim/Discovery/user_manual/volumeextract.html?q=extract

https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v241/en/flu_ug/tgd_user_workflow_guided_tasks_capping.html?q=enclose%20caps

[dungnguyenxuan199566]

Hi Essence,

 

Thank you for your kind help. I wonder if you can share student links for me.

I am using student version and does not have account number.

 

Thank you!

[Essence]

If you are unable to access the link, follow this Forum discussion /forum/forums/topic/using-help-with-links/#latest

[dungnguyenxuan199566]

Hello Essence,

The guide in the link you sent does not work in my pc. The website after I paste your links looks like this:

[Essence]

Which version of Ansys are you using?

[dungnguyenxuan199566]

Hi,

Mine is Fluent 2023 R2.

[Essence]

Could you please check again using the Forum discussion steps? Check if the Windows has blocked the links from opening as a firewall.

[dungnguyenxuan199566]

Hi,

It seems like the web browser does not block any website. Is there any way I can change the default web browser open by Fluent to try on Chrome?

[Essence]

 

Hang on. I will get back on this.

 

[dungnguyenxuan199566]

Hi Essence,

Thank you very much for your kind help. I am looking forward to hearing from you.

Besides, is volume extracting this step (picture below)? If yes, my whole object is defined as a single regions only. How can I separate my object into multiple regions (like inlet, body, etc.) for my purposes?

[Essence]

Could you try this link:

/forum/forums/topic/how-to-access-the-ansys-online-help/

[dungnguyenxuan199566]

Hi, I tried from Spaceclaim. And the same issue:

[Rob]

Can you edit the stl in the original software to just leave you with the vessel walls? When I did the lung models I adjusted the stl before going into the Ansys tools. 

[dungnguyenxuan199566]

Hi Rob,

Would you please explain more clearly? I did make it hollow as you see in the picture with open mouth for inlet air.

[Rob]

 

When I did it the last time, I trimmed the inlet (top) and ends of the 4th level branches to leave me with a single surface with one large & several small holes. I then capped those in the geometry/meshing tool of the time and went from there. 

Same approach was used when I did the pulmonary artery example that finished up in Fluent News (before Ansys bought the company). Spring 2003 edition. 

 

 

[dungnguyenxuan199566]

Hello Rob,

Thank you for your explanation. Would you mind explaining in more detail in this step " capped those in the geometry/meshing tool"?

I think this is the step where I am stuck in. That would be great if you could attach some pictures. When I import my stl file in fluent mesh, it shows as one single object and I cannot select the inlet (top). What I did was: 

1, Open workbench, select, geometry, then import stl file.

2, Select edit in Spaceclaim, in the Spaceclaim, I select autofix in facets tools.

3, Then, I move it to fluent mesh.

but in the fluent mesh, I could not select inlet regions for capping (as inlet), please find pictures below.

[Rob]

You currently have a solid zone that is the lung wall. When I did the work I trimmed the geometry to have a single shell surface with holes where I wanted the flow. These were capped & labelled so when moving to TGrid (now Fluent Meshing) I had zones for wall, inlet & 8-16 outlets. Much mucking about was then done as the tools have improved in the last 20+ years and 2 weeks later I had a tet mesh. 

[dungnguyenxuan199566]

Would you please specify " trimmed the geometry to have a single shell surface with holes where I wanted the flow" and "capped & labelled" steps? Did you do this before exporting stl file or after you have stl file. And which software did you use to trim and capped, labelled the geometry? Is there anyway we can trim, cap, and label the stl file?

[Rob]

The artery/lung you have looks to be a solid volume of the vessel wall, ie it has a thickness. In my model we had a single shell (surface not volume). I trimmed the ends off in Magics (Materialise product) to import just the wall into GAMBIT (very old Fluent pre-processor). I then capped the ends, remeshed and fixed the geometry with a mixture of GAMBIT and manual node repairs in TGrid (now Fluent Meshing). This took several weeks. 

Your approach now may be to tidy the stl up in whatever you used to generate it (Magics or Simpleware [Synopsys product] would be my choices now except I don't have a licence), cap the ends in SpaceClaim and then mesh. 

[dungnguyenxuan199566]

Hi Rob,

I agree, mine is volume one. Can we do something like converting the volume solid one to a surface one?

[aarshad.phd20smme]

Hi Xuan Dung! What is the format of your geometry file?

[dungnguyenxuan199566]

Hi,

Mine is STL file one.

[Rob]

To convert you can throw away one of the main faces, but which one is up to you. Hence me suggesting looking at whatever software was used to generate the stl.