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problem with constant wall heat flux

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Old   February 4, 2010, 07:46
Default problem with constant wall heat flux
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hi foamers

i want to use a fixed heat flux boundary condition in a conjugate heat transfer problem i use fixedGradient boundary condition on T ;

type fixedGradient;
gradient uniform 10.417;

i know that

heatflux = thermal conductivity (k) * tempreature gradient (dT/dN)

so for k=12 , heatflux=125 w/m2 >> gradient=heatflux/k=10.417

please help me ,, is that right to describe my constant heat flux (125 w/m2) in OpenFOAM ..

thank you very much ..
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Old   February 4, 2010, 09:46
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Stefan Herbert
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this is the right way. Go on like this.

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Old   June 23, 2014, 14:23
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Ian Dizon
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hello, i am trying to set up something similar where i have a constant heat flux.
in my case i have lamps heating up air in a room.

my question is: would k be a property of the air? or of the lamp
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Old   June 24, 2014, 03:07
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Bárbara Arizmendi
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It depends on where you are fixing the heat flux. If you have simulated the lamp then you use the conductivity of the lamp. If you haven't simulated the lamp then you have to calculate the convective heat transfer coefficient (hc) or you can fix a HeatFlux boundary condition.

Last edited by Barbara; June 24, 2014 at 03:08. Reason: lexical mistake
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Old   July 16, 2014, 08:30
Default multiregion solid conduction
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I am also trying to do something similar and the option to fix the Gradient of T works fine but only if you have solids with the same k (thermal conductivity). If there are different domains with different k's the results are not as expected comparing with COMSOL or FLUENT applying the actual heat flux boundary value.

Has anyone dealt with something like this in ChtMultiRegionFoam if yes any advice would be really helpful!!!

Thanks in advance

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Old   August 15, 2016, 16:20
Default heat flux setting
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I have case that their is constant heat flux from ground and i put it 500 w/m2

but their is a problem that it is not effect the density of the air or it's velocity

during solving and after calculation

please help
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Old   January 13, 2019, 08:18
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Jianrui Zeng
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If I use fixedGradient BC for constant heat flux, should thermo conductivity be constant? if it is changing with T, how should I get constant heat flux? Thank you.
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