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April 15, 2014, 01:47 |
combustion, solution problem
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#1 |
Member
Jinwhan Ryuk
Join Date: Feb 2013
Location: South Korea
Posts: 91
Rep Power: 13 |
Does anyone have blinking problem while the problem is solving? I am solving coal combustion problem and it has 1 million nodes size. Once I start parallel running then solver is running and then Out file screen go upward and dowward for a long time at 1st iteration and then move to 2nd iteration. 2nd iteration also shows the same phenomena. One iteration takes about 40 minutes. Please help me!
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April 15, 2014, 02:48 |
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#2 |
Senior Member
Bharath kumar
Join Date: Apr 2009
Posts: 169
Rep Power: 17 |
I think this is memory problem.
What is your system configuration?Combustion will take more time to solve. Reduce your mesh size and try again. |
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April 15, 2014, 04:48 |
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#3 |
Member
Jinwhan Ryuk
Join Date: Feb 2013
Location: South Korea
Posts: 91
Rep Power: 13 |
Thank you very much for your fast reply. I am using 64gigabite memory. According to windows manager, 10.6GB meories are used. The problem is that CPU. CPU shows only 1% usage and suddenly goes up 90%. I also use SSD and Intel i7-4930K@3.40GHz CPU.1 million cell is not enough for my problem. This is the minimum number to avoid overflow calculation.
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April 15, 2014, 05:43 |
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#4 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,700
Rep Power: 143 |
Something sounds seriously wrong with your simulation. You probably have a poorly set up physical model. Are you using radiation modelling? A poorly set up radiation model can do that sort of thing.
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April 17, 2014, 05:11 |
Coal combustion tutorial radiation setup
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#5 |
Member
Jinwhan Ryuk
Join Date: Feb 2013
Location: South Korea
Posts: 91
Rep Power: 13 |
Thank you very much for your reply. Thermal Radiation: Discrete Transfer, Number of Rays:32, Emissivity: 1, Target Coarsening Rate: 16, some walls emissivity: 0.6 I just followed coal combustion tutorial setup. Is it so sensitive that show such a problem? Could you tell me how to fix this? 24 iterations take 48hours now...I tried number of rays and emmisivity but it didn't help. As far as I know Discrete Transfer model is the only one that can adapt coal combustion problem, isn't it? What kind of radiation solving options which I can chose?
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April 17, 2014, 21:55 |
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#6 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,700
Rep Power: 143 |
Well, the radiation model is the problem. You may need some serious CPU time on the radiation model - that depends on the detail of what you are modelling.
I recommend you start with a simple model where you have a known answer to reproduce and check the radiation model is behaving as expected. Only once you have a good feel for the radiation model should you attempt the large complex model. |
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April 18, 2014, 03:43 |
I found some clue.
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#7 |
Member
Jinwhan Ryuk
Join Date: Feb 2013
Location: South Korea
Posts: 91
Rep Power: 13 |
Thank you very much for your help. You are definately right! I put inapropriate options in radiation setup. I look over my model again and change some variables. It works now.
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