topic Re: Radiation in thermal simulation is not working in Fusion Support Forum

Radiation in thermal simulation is not working

bhardwajshastri — Thu, 30 May 2019 12:48:02 GMT

Hej there !

I want to run thermal simulation on CAD model of satellite. After applying thermal loads and other require information, when I start to solve,

1. By on cloud method : It just loads till 76%, and then nothing happens. (waited for one whole day to load further)

2. By local method : After generating mesh, it loads till 1% and then nothing happens. (again waited for one whole day to load further).

This issue occurs only when I have radiation as one of the thermal loads. If I remove radiation from thermal loads, thermal simulations works perfectly. But, I need radiation as one of my thermal loads. I am open to any helpful suggestions. Thank you in advance.

Re: Radiation in thermal simulation is not working

John_Holtz — Thu, 30 May 2019 15:39:11 GMT

Hi @bhardwajshastri

As the saying goes, I know enough to be dangerous. But perhaps something here will help with your situation. (If it does not help, exporting your model to a Fusion 360 Archive (.f3d) and attaching your model will help.)

I just did a test model with radiation, and the analysis does solve. One thing to keep in mind is that radiation is a nonlinear load, so the analysis performs an iterative solution. What cannot be predicted is how many iterations will be needed to converge, so the analysis runtime can be much longer. For example, if an analysis without radiation solves in 10 minutes, an analysis with radiation that requires 50 iterations to solve will run for 500 minutes.

The analysis performed locally will provide the most feedback because you have access to the log and output files (.LOG and .OUT). The question is what is in these files? (For a cloud solve, you can access the .OUT file after it completes from the "Results > Solver Data > Solver Output" command.) For example:

How many GRID POINTS are there? (Check for a section titled MODEL DATABASE SIZE in the file)
How many Elements?
If the analysis go to the point where it is performing iterations, there will be output that looks like this. Did it get this far? Is the analysis converging? (The PERCENTs should approach 100.)

N O N L I N E A R  I T E R A T I O N   S U M M A R Y

 ITERATION   DISPLACEMENT          LOAD              WORK       
   NUMBER   ERROR   PERCENT   ERROR   PERCENT   ERROR   PERCENT
       1    4.93E-01    0.0   2.28E-02    4.4   2.28E-02    0.0
       2    8.63E-04    0.1   6.27E-04  100.0   4.22E-06   23.7
       3    1.69E-05    5.9   1.38E-05  100.0   3.48E-09  100.0
       4    2.76E-09  100.0   7.02E-09  100.0   8.93E-16  100.0

Re: Radiation in thermal simulation is not working

bhardwajshastri — Thu, 30 May 2019 17:13:51 GMT

Greetings Mr. Holtz,

A little bit of something is better than nothing. Little by little, a little becomes a lot. Thank you again for quick response. My doubt is almost solved. Just a couple of few questions, if you don't mind.

Firstly, while simulation is running locally, can I access log files ? If so, how ?

Secondly, after receiving your reply. I ran a simple radiation simulation on cube. Still same issue is repeating. So maybe, its possible that, I am doing something wrong. Can you please share your quick simulation test, with thermal loads information and other stuffs, if possible? or you can direct me to any specific tutorial ?

Thank you.

Re: Radiation in thermal simulation is not working

John_Holtz — Thu, 30 May 2019 19:23:50 GMT

Hi,

The local files should be located in the following folder. (If not, then search for the file "gewiz.nas" to locate it.)

Open File Explorer
Enter %TEMP% in the address bar. This will open a folder like "C:\Users\yourname\AppData\Local\Temp".
Browse into the Neutron folder.
The folders "AFEA_Solution_......" are where the local files are saved.

I have attached my model. If it does not help you to find the problem, please attach your test model for me to look at.

Re: Radiation in thermal simulation is not working

bhardwajshastri — Thu, 30 May 2019 20:03:28 GMT

Hello again,

It worked perfectly on my model. Thank you once again for your help.