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Static temperature remains constant in a combustion simulation |
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August 10, 2021, 05:10 |
Static temperature remains constant in a combustion simulation
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#1 |
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Join Date: Aug 2021
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Hi, i've been trying to get a combustion simulation of a hydrogen/methane mixture working by using the reduced GRIMECH 3.0 kinetics and transport given by fluent. The transport properties seem to work correctly as the contours for the system show expected results.
I need to get a contour of the static temperature, but it only varies in like 0,5K and i don't really know why as im trying to simulate combustion. With the individual components and a simpler mechanism, it works just fine. Should I deactivate the tracking of the reaction intermediates? Is something wrong with the thermo file? Thank you in advance |
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August 10, 2021, 19:37 |
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#2 |
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Lorenzo Galieti
Join Date: Mar 2018
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So the species distribution is reasonable but the temperature is not? Is it cold everywhere as if there was no flame?
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August 11, 2021, 04:07 |
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#3 | |
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Quote:
I've tried to reduce step time, increase the number of iterations, but that point converges and Fluent does not get anywhere else. |
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August 11, 2021, 06:40 |
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#4 |
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Lorenzo Galieti
Join Date: Mar 2018
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Usually you need some manner to kickstart the combustion, a sort of numerical spark if you want.
So basically, you should patch (i.e. impose) the combustion chamber region with a high temperature (1800K) once the cold flow is properly developed, as in your case. Just google “fluent patch region” and you should find plenty of instructions on what to do |
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August 12, 2021, 05:51 |
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#5 | |
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Thank you for your help |
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August 12, 2021, 06:45 |
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#6 |
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Lorenzo Galieti
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I usually patched the whole combustion chamber . If you see it diverges, either underelax a bit the equations for 20-30 iterations or, if you are using pseudo transient method, set a lower multiplicator
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fluent, grimech, static, temperature |
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