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CFD Boundary Conditions for Journal Bearings

Posted 29 set 2011, 08:29 GMT-4 Fluid & Heat, Computational Fluid Dynamics (CFD) Version 4.1 2 Replies

Toan Nguyen
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Hi all,

I have recently started working with Comsol. It seems very easy to use and so far I was able to build my model and have the basic physics working. I am trying to build a journal bearing model which gives me a realistic fluid film pressure distribution for different shaft speeds and loads. Using the pressure I would then like to calculate the fluid friction and with that the heat distribution within the bearing.

The journal bearing tutorial was very helpful, however it does not solve gaseous effects such as cavition. Comsol support told me that they are working on that but it will not be available any time soon. There are many ways to simulate journal bearings without calculation cavitation, one is be setting the right boundary conditions such as Reynolds, Gümbel, etc. as explained by Schweizer (Schweizer B., "ALE formulation of Reynolds fluid film equation", 2008).

The question is: How/Where do I set these boundary conditions? By using global equations? I have tried to set up global equations but did not succeed - maybe I did it wrong? I have included the model I am working on. The fluid streamlines and most parts of the pressure seems right.

Can anyone help?
Thanks,
Toan
2 Replies Last Post 11 apr 2013, 12:00 GMT-4
Andreas Schwarz
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Posted: 1 decade ago 6 ott 2011, 14:37 GMT-4
Hi, I am also working on a model for a journal bearing using the 'Lubrication Shell (tffs)' and the 'Solid Mechanics (solid)' modules. I only started using this software very recently and still have a lot to learn. In terms of which boundary conditions you specify depends on which physics module(s) you are using in your model.

This brings up my question: Depending on which module you are using how do you apply the bearing loads to your model?

Any feedback would be greatly appreciated.
Andreas.

P.S. I was attempting to open your model, but I do not have the CAD Import Module.
Hi, I am also working on a model for a journal bearing using the 'Lubrication Shell (tffs)' and the 'Solid Mechanics (solid)' modules. I only started using this software very recently and still have a lot to learn. In terms of which boundary conditions you specify depends on which physics module(s) you are using in your model. This brings up my question: Depending on which module you are using how do you apply the bearing loads to your model? Any feedback would be greatly appreciated. Andreas. P.S. I was attempting to open your model, but I do not have the CAD Import Module.
Rob Eling
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Posted: 1 decade ago 11 apr 2013, 12:00 GMT-4
The question on including cavitation effects in fluid bearings was raised in 2011; I was wondering if there are already solutions available within Comsol to include cavitation effects in thin film laminar flow? Can anyone give me some hints?
The question on including cavitation effects in fluid bearings was raised in 2011; I was wondering if there are already solutions available within Comsol to include cavitation effects in thin film laminar flow? Can anyone give me some hints?

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