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Transient heat transfer

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Hi everyone

I'm struggling with a case of heat transfer from hot billet to a cold billet bay. I have started with a simplified model with no convection. The ultimate goal is to analyze thermal stress within different scenarios.
So, I've tried a hole lot of different BC's, but I can't get no convergence.

Any ideas?


2 Replies Last Post 25.11.2014, 15:36 GMT-5
Mikael Noerregaard Nielsen

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Posted: 10 years ago 25.11.2014, 06:06 GMT-5

Hi everyone

I'm struggling with a case of heat transfer from hot billet to a cold billet bay. I have started with a simplified model with no convection. The ultimate goal is to analyze thermal stress within different scenarios.
So, I've tried a hole lot of different BC's, but I can't get no convergence.

Any ideas?


The model is rather complex. Have you tried modeling one physics at the time and then adding on? I would start off by only doing the Solid Mechanics, then the Heat Transfer and finally contact analysis. Solver settings is also a way to go as you have both contact analysis and radition, so the model is non-linear - check the knowledge base and/or forum and/or see the following links:
Contact analysis: www.comsol.com/community/forums/general/thread/34/
Solver settings: community.cmc.ca/docs/DOC-1453

Your mesh also seems very coarse for contact analysis. See also the Snap Hook model in the Model Library

Best Regards

Mikael
[QUOTE] Hi everyone I'm struggling with a case of heat transfer from hot billet to a cold billet bay. I have started with a simplified model with no convection. The ultimate goal is to analyze thermal stress within different scenarios. So, I've tried a hole lot of different BC's, but I can't get no convergence. Any ideas? [/QUOTE] The model is rather complex. Have you tried modeling one physics at the time and then adding on? I would start off by only doing the Solid Mechanics, then the Heat Transfer and finally contact analysis. Solver settings is also a way to go as you have both contact analysis and radition, so the model is non-linear - check the knowledge base and/or forum and/or see the following links: Contact analysis: http://www.comsol.com/community/forums/general/thread/34/ Solver settings: https://community.cmc.ca/docs/DOC-1453 Your mesh also seems very coarse for contact analysis. See also the Snap Hook model in the Model Library Best Regards Mikael

Henrik Sönnerlind COMSOL Employee

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Posted: 10 years ago 25.11.2014, 15:36 GMT-5
Hi,

Two suggestions:

1. Start by a stationary analysis and use it for the initial conditions of the time dependent analysis.

2. Be careful with setting appropriate scales on the dependent variables, particularly displacement and contact pressure.

Regards,
Henrik
Hi, Two suggestions: 1. Start by a stationary analysis and use it for the initial conditions of the time dependent analysis. 2. Be careful with setting appropriate scales on the dependent variables, particularly displacement and contact pressure. Regards, Henrik

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