evaluation of Heat Equation on a plane with a Heat source and convective b.c.

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Lorenzop99
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evaluation of Heat Equation on a plane with a Heat source and convective b.c.

Post by Lorenzop99 »

Hello everidbody

i want to say that i'm new about Elmer and i need some help.

i've started to study a Inconel Plane with dimension of 2mmx6mmx340mm with a heat source of 0.78 MW/m^2.

You can see the b.c. at the image at this link:
https://ibb.co/3MLZKVv

i have three doubt:

in particular i'll want to set this boundary condition:

1)the top, left, right, forward and behind surface: Adiabatic boundary condition, is it correct asses this condition adding an heat flux=0?
2)below surface: convection b.c., is it correc set this condition adding the value of heat transfer coefficient in W/m^2 K and temperute?

3)About the body force i'll want to add the Heat source of 0.78 MW/m^2, how can i set?

thanks to those who answer me!
kevinarden
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Re: evaluation of Heat Equation on a plane with a Heat source and convective b.c.

Post by kevinarden »

Have you reviewed the Elmer's Model Manual Heat Equation and then worked through
the first two tutorials in the tutorial manual
https://www.nic.funet.fi/pub/sci/physics/elmer/doc/
Lorenzop99
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Re: evaluation of Heat Equation on a plane with a Heat source and convective b.c.

Post by Lorenzop99 »

Thank you for the answer; i've already make the two tutorial, unfortunately I couldn’t solve the problem
kevinarden
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Re: evaluation of Heat Equation on a plane with a Heat source and convective b.c.

Post by kevinarden »

1) I believe the default "do nothing" boundary condition is Adiabatic, so if you assign nothing the heat flux will be zero. You can also assign heat flux = 0.
2) You can make the bottom surface radiate heat using idealized radiation, external temperature, and an emmisivity factor
3) Body force is assigned using the body force option

You should specify an initial condition temperature, or it will assumed to be zero.
You should do everything in SI units.
case.sif
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result.png
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Lorenzop99
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Joined: 28 Apr 2021, 14:39
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Re: evaluation of Heat Equation on a plane with a Heat source and convective b.c.

Post by Lorenzop99 »

Thank you for all!

The last doubt is about the second point:

2) i don't have radiation boundary condition but a convection Boundary condition, how can i set this kind of b.c.?

about the measure conversione for to pass to W/m^2 to W/kg you is correct divide for the density and for the thickness?


you can find my sif case is attachment
case.sif
(2.31 KiB) Downloaded 22 times
Thank you!
kevinarden
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Joined: 25 Jan 2019, 01:28
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Re: evaluation of Heat Equation on a plane with a Heat source and convective b.c.

Post by kevinarden »

I believe that can be done as a heat flux BC

[attachment=0]case.sif[/attachment

If you just want it to convect by the coefficient then you don't need to enforce a flux

Boundary Condition 1
Target Boundaries(1) = 5
Name = "heatflux"
Heat Flux BC = True
Heat Transfer Coefficient = 1
End
Attachments
case.sif
(2.13 KiB) Downloaded 20 times
Lorenzop99
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Joined: 28 Apr 2021, 14:39
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Re: evaluation of Heat Equation on a plane with a Heat source and convective b.c.

Post by Lorenzop99 »

thank you!
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