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## Problem with Modeling a multi-stage agitated vessel

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Enefiok Akpan

December 9, 2012 2:53am UTC

Problem with Modeling a multi-stage agitated vessel

Hi all,
I am having problem getting my model to run and converge. I am trying to model a six-stage agitated vessel in 2D. I have followed the steps described in the posted modeling of baffled mixer vessel using rotating machinery physics in comsol documentation to create my geometry and in building my model. The model in comsol documentaion is in 3D but I am trying to do it in 2D first before going to 3D. The fluid being water enters the rotating domain at the bottom and exits at the top. The botom boundary in the rotating domain is set to inlet while the top boundary in the rotating domain is set to outlet. All the the exterior boundaries are set to non-rotating wall. The impeller speed is gradaully stepped up from 0 to 10 rev. per seconds using step function within 2 seconds from t = 0. The input velocity and pressure could be changed as well as the impeller speed. I am saying this as I do not know if any of these inputs could play a role in the model not running but I doubt it being the cause. Could someone who have experience with this kind of modeling help me figure out what the problem is? I have attached my file to help you fully understand what I have done so far. Thank you for helping.

Enefiok

Luke Gritter
Certified Consultant
AltaSim Technologies

December 10, 2012 6:47pm UTC in response to Enefiok Akpan

Re: Problem with Modeling a multi-stage agitated vessel

Enefiok,

For the Rotating Machinery interface in 2D, the axis of rotation must be in the out-of-plane direction. You will need to use a 3D model to capture the behavior of the six-stage vessel.

Luke

Enefiok Akpan

December 13, 2012 3:25am UTC in response to Luke Gritter

Re: Problem with Modeling a multi-stage agitated vessel

Enefiok,

For the Rotating Machinery interface in 2D, the axis of rotation must be in the out-of-plane direction. You will need to use a 3D model to capture the behavior of the six-stage vessel.

Luke

Hi Luke,
Thank you so much for your suggestion. I will probably have to try and develop a simple 3D geometry to try it out. This is going to be challenging as I am not very good in developing geometry using comsol and I do not know or have CAD. Thanks.

Enefiok

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