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rotating machinery

Posted 28 sept. 2011, 01:18 UTC−4 Low-Frequency Electromagnetics, Fluid & Heat Version 4.2, Version 4.2a 10 Replies

Sylvana Garcia
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Hi

I'm trying to simulate a stirring tank, but my model doesn't converge. The parameters are exactly the same as another model with a different, simpler impeller. I just don't know where to begin. Does anyone have any idea? My model is attached.

Thanks!

Attachments:

10 Replies Last Post 27 mars 2015, 05:53 UTC−4
Amir Fadel
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Posted: 1 decade ago 28 sept. 2011, 09:32 UTC−4
Hi,

Modifying the mesh and modifying the step function, it works. In this case luckily the automatic mesh is sufficient.
The file is too big to be uploaded with the solution so you will have to re-compute it.

Cheers
Hi, Modifying the mesh and modifying the step function, it works. In this case luckily the automatic mesh is sufficient. The file is too big to be uploaded with the solution so you will have to re-compute it. Cheers

Attachments:

Sylvana Garcia
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Posted: 1 decade ago 28 sept. 2011, 11:29 UTC−4
Hello, Amir

Wow! Thank you so much! Yes, the model is now running successfully! Thank you very, very, very much!!!!

Sylvana
Hello, Amir Wow! Thank you so much! Yes, the model is now running successfully! Thank you very, very, very much!!!! Sylvana
Sylvana Garcia
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Posted: 1 decade ago 18 nov. 2011, 11:38 UTC−5
Hi

Now I'm trying to increase the angular speed in the original model to 300 rpm. When I try to run the model, it takes too long, several days! I haven't even had tha patience to wait until it stops. I thought it might be because it now needs to be turbulent, so I'm using the turbulence model. Is there any chance anyone could take a look at my model and comment on anything I'm missing?

Thanks!
Sylvana
Hi Now I'm trying to increase the angular speed in the original model to 300 rpm. When I try to run the model, it takes too long, several days! I haven't even had tha patience to wait until it stops. I thought it might be because it now needs to be turbulent, so I'm using the turbulence model. Is there any chance anyone could take a look at my model and comment on anything I'm missing? Thanks! Sylvana
Jason Castro
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Posted: 1 decade ago 18 nov. 2011, 14:09 UTC−5
Hi Silvana

I am doing the same. I have a baffled stirred mixer, impeller es a turbine. I am using turbulent model too. Now is runing, but very slow. Maybe something is wrong, when i used laminar model, the solver did not converge. Re is 20000.

What i have to do?
Hi Silvana I am doing the same. I have a baffled stirred mixer, impeller es a turbine. I am using turbulent model too. Now is runing, but very slow. Maybe something is wrong, when i used laminar model, the solver did not converge. Re is 20000. What i have to do?
Jason Castro
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Posted: 1 decade ago 18 nov. 2011, 14:23 UTC−5
What tipe of changes did u do to step funtion and mesh??? I cant see the file because i have COMSOL 4.1. I attached my model.
What tipe of changes did u do to step funtion and mesh??? I cant see the file because i have COMSOL 4.1. I attached my model.
Jason Castro
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Posted: 1 decade ago 21 nov. 2011, 16:28 UTC−5
Hi Amir

I have COMSOL 4.0, then i can´t see the files. I want to know what change did you do to mesh and step function?
I have the same problem.
Hi Amir I have COMSOL 4.0, then i can´t see the files. I want to know what change did you do to mesh and step function? I have the same problem.
Sylvana Garcia
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Posted: 1 decade ago 22 nov. 2011, 13:04 UTC−5
Hi, Jason

Amir decreased the "location". It was 1, and he changed it to 0.1. He used the physics-controlled mesh with "normal" size.

Sylvana
Hi, Jason Amir decreased the "location". It was 1, and he changed it to 0.1. He used the physics-controlled mesh with "normal" size. Sylvana
Jason Castro
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Posted: 1 decade ago 23 nov. 2011, 10:03 UTC−5
Hi Sylvana

I want to know ,if can you run your last program with 300 rpm in turbulent flow.
Maybe, Could you send me,please, your last work?

Jason
Hi Sylvana I want to know ,if can you run your last program with 300 rpm in turbulent flow. Maybe, Could you send me,please, your last work? Jason
Amir Fadel
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Posted: 1 decade ago 24 nov. 2011, 09:53 UTC−5
Hi,

Given the Re you have you must definitely use a turbulence model. I did run your model and works fine I just relaxed the mesh to Coaser, you need to be careful whether the results make sense.

I had to delete the first solver to save space, you can simply re-run it and then run the second solver.

Cheers
Hi, Given the Re you have you must definitely use a turbulence model. I did run your model and works fine I just relaxed the mesh to Coaser, you need to be careful whether the results make sense. I had to delete the first solver to save space, you can simply re-run it and then run the second solver. Cheers
Janagani Bharadwaj
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Posted: 10 years ago 27 mars 2015, 05:53 UTC−4
hi

I developed a simple autoclave (which has two sets of impeller blades to hollow rotating shaft placed at different positions )in 3D, rotational machinery laminar flow as my physics and time dependent as my study. While computing i am getting the following errors
1.Nonlinear solver did not converge.
2.Maximum number of segregated iterations reached.
Time : 0
3.Last time step is not converged.

I am using extreme coarse as my mesh.
Then i changed my mesh to normal and i got some 40lakhs DOF and taking some days to give the result and i am not sure it will give the result. I am using windows 8, 64 bit,8GB RAM

Can anyone guide me how to overcome the above errors.

Quick reply will be highly appreciated as it is very very urgent because it is my PG project work.

Many thanks in advance.
hi I developed a simple autoclave (which has two sets of impeller blades to hollow rotating shaft placed at different positions )in 3D, rotational machinery laminar flow as my physics and time dependent as my study. While computing i am getting the following errors 1.Nonlinear solver did not converge. 2.Maximum number of segregated iterations reached. Time : 0 3.Last time step is not converged. I am using extreme coarse as my mesh. Then i changed my mesh to normal and i got some 40lakhs DOF and taking some days to give the result and i am not sure it will give the result. I am using windows 8, 64 bit,8GB RAM Can anyone guide me how to overcome the above errors. Quick reply will be highly appreciated as it is very very urgent because it is my PG project work. Many thanks in advance.

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