Sliding Mesh Problem
Hi All,
I am trying to solve an axial fan problem and i realized that if i use mrf model, i couldnt calculate the real torque value because of the fluid motion in the mrf zone. I would like to calculate the real torque value. I mean if i use mrf model, the fluid in the mrf zone is rotating with the value i described. Than i thought that if i use sliding model or dynamic mesh model, it would be more accurate solution. But i tried to use sliding mesh model and i activate mesh motion instead frame motion(same rpm). When i tried to calculate again, fluent is giving me a mesh error. The error is negative volüme detected. But i check mesh before analysis, there was not any negative volume. Also when i do it with frame motion, there is no any problem about mesh. I can solve the problem within real velocity and pressure values. What should i do to calculate the real torque value? Can anyone give me a udf for dynamic mesh? or any advise about sliding mesh? Thank you! Have a good day |
Have you solved the problem? Is it a 2D simulation?
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No, i didnt solve it yet. It is a 3D problem.
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Hi,
For a sliding mesh, you need a perfect interface between the rotor and the stator. Then from your mrf setup, you can type in the fluent consol : Code:
/define/boundary-conditions/modify-zone/mrf-to-sliding-mesh Aurelien |
I think i have good interface between rotational and stationary bodies. I dont have stator its only a blade in the mrf zone and inlet, outlet bodies which has pressure inlet&outlet with 0 pa. They are from new part zones and interface is created automatically. Should i make this connection by using fluent interface or is it enough to make in form new part?
Thank you Aurelien! |
Well, if you don't have a stator cellzone, you didn't need any interface.
From what you are saying, you just need to : 1) activate the sliding mesh option 2) define the rotating velocity, 3) check the axis and the origin. 4) in the dynamic mesh menu, you shouldn't have anything activated. EDIT : By stator, I mean "not rotating volume". |
Ah than yes i have stator volume.
I did that options but an error has been occupied when i ran the calculation. The error is negative mesh volume detected. But if i use mrf model and run calculation there isnt a problem. |
Check out this.. It may help you
https://www.youtube.com/watch?v=KFrZoDWUC5s |
I solved it. In order to help other people i will explain how i solved it.
I refined the mesh and i used fluent interface instead form new part model. However i already couldnt calculate the real torque value. In my opinion, it is only calculateable when use dynamic mesh model. And i cant write an udf for that case. |
I still could not calculate the torque value, searched on the forum but there is no any valid solve about this problem.
I tried to set the referance value to area: blade and hub surface area and length: blade Radius but still couldnt reach the experimental torque value. I guess this topic is the biggest problem of fluent software. :D If some super hero WHO has perfect fluent skills can solve this problem, please notifiy me on that topic. |
contact with me on 12317@eng.asu.edu.eg please
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Do you have a problem in contacting me?
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No, I've sent you an e-mail.
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