[Thermal_engg]

Hi everyone,
My problem is simple (I hope), a solid copper cylindrical pipe ,bottom half of which is subjected to a constant heat flux from below, in the presence of gravity, due to which it will be gradually heated and natural convection will start.The domain i am taking is a cylinder of a much larger diameter whose cross-section is concentric with the cross-section of the given copper tube.

What I have done so far...first created the small copper pipe in design modeler by extruding the circular surface created and using option "Add material".
Next drawing a concentric circle to the previous circle and extruding it by the length same as that of the copper pipe and choosing option "Add Frozen".
Next , I used the Boolean subtract operation to subtract the smaller pipe from the larger cylinder(domain).

Now the problem starts when I try to mesh this hollow cylinder formed.tried different methods but everytime it shows some error during meshing.I am attaching picture of the hollow cylinder for better understanding.The tiny bright portion at the centre of the PIC is the hollow created after boolean subtraction.


Any help on this topic will be appreciated.Thnx

[mvoss]

cut the full model 2 times by 90 deg. with "imprint" on the outermost faces.. this will help the mesher to decide where to put nodes.

[Thermal_engg]

I tried doing what you said. Firstly I created a "New sketch" of 4 lines.Then "Lines from sketches". After that I projected those lines on the hollow-circular surface.

Then firstly I extruded the hollow-circular cross section and then again extruded the new sketch of 4 lines,only this time selecting "Imprint" and "to next surface". This operation was successful and I obtained the required geometry.But again while meshing,it shows "Exception occured during mesh file export,please send your data to your service provider".

Could you please tell me where am I going wrong? I am enclosing pictures of the geometry ,wireframe and mesh generated.Thnx

[mvoss]

can you use ICEM?
did you tried the mapped meshing and sweep?
do you have a licence cap (max. number of cells > 500.000)

[Thermal_engg]

Originally Posted by mvoss

can you use ICEM?
did you tried the mapped meshing and sweep?
do you have a licence cap (max. number of cells > 500.000)

No. of cells is around 200,000.I use institute system so I don't know about licence cap.
I tried mapped face meshing, showing error - "Mesh generated not of acceptable quality" .
I did not try "sweep" option as I don't have any idea about it..

Also I have never used ICEM. Will using it lessen my problem?...Thnx

[mvoss]

with this "easy" geometry you will have no problems in ICEM-hexa (check youtube and the tuts IF you don´t change the geometry in future or run FSI and such) ... but still it should be possible with the ansys meshing.

Check the geometry for "sweepable bodies".. this is simply extruding and cutting a surface mesh(1st) towards another (2nd) surface of same topology. And this i basically the same thing you would do in ICEM (simply spoken).

you can send me the wb-archive if you like and i can give the sweep a try.

Matthias

[Thermal_engg]

Ok ,I will give a try to ICEM.But still I think that at least such a geometry should be possible through ANSYS Meshing tool.
I think I attached an archive and replied to the alert I got through gmail regarding this thread.anyways I am giving a google drive download link for the files.---- https://drive.google.com/folderviewi...nM&usp=sharing

[mvoss]

Link is broken

[Thermal_engg]

if u can give me ur email-id, i can mail you the winrar package,otherwise i will retry with google drive

[Thermal_engg]

https://docs.google.com/file/d/0B3sL...it?usp=sharing

[mvoss]

hope this helps

[Thermal_engg]

Thanks for your efforts mate...,though I think the problem lies in the software itself as I tried meshing a simple rectangle,even then it was able to mesh and display the same error of being unable to export,seems like a problem with fluent, so now I am gonna have to reinstall the whole software..