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Old   February 4, 2014, 12:39
Default Calculate heat flux direction
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Dear all,

is it possible to calculate the heat flux for each direction (i.e: \dot{q}_{x}= ... , \dot{q}_{y}= ... , \dot{q}_{z}= ... ) ?

I want to simulate the heat transfer from a plate to ambient air ... velocity is s.th round 2 m/s ...

is there a way to do this with "Additional Variable" ? if yes, how is the workflow ? At the moment I'm just using AV for gradient calculations ...

thanks in advance !
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Old   February 4, 2014, 18:22
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You can calculate these heat fluxes from the thermal conductivity equation if it is a solid domain. Or is it a fluid domain?
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Old   February 5, 2014, 03:21
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hi glenn and other cfd-user,

as supposed it's a fluid domain ... but i'm calculating the fluid with \lambda = const. ... so i can use the thermal conductivity equation for my fluid, too ?! or am i wrong ?

thanks in advance !
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Old   February 5, 2014, 06:27
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In a solid domain you can get the thermal fluxes from the gradient of temperature in the body as the only heat transfer is from conduction. But in a fluid you have conduction and convection, and possibly other mechanisms as well. I guess you can look at the temperature (or enthalpy) gradient here too.
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Old   February 5, 2014, 12:15
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hi glenn,

its always nice to hear your point of view ... anyway ... i assume that i have thermal conductivity in a fluid with const. thermal conductivity ... for this case i calculated my heat transfer for all three directions ... at the moment i have no verification for the results ... what i have done is that i compared the contour plot of the grad q with the streamlines (see attached)

in a further step i want to calculate the heat transfer for a 1D problem analytical and compare the value with CFX ... or does anyone has a better idea ?

- thanks
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