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Defining Boundarys by a non thermal flow

Posted Jun 5, 2012, 7:39 a.m. EDT Version 4.2a 5 Replies

Igor Polushkin
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Hello,

I´m using a non thermal flow modul, wich consists of 2 parts. One is liquid, the other is solid. I`m trying to simulate the liquid flow, but I cant consider the solid part, because Comsol doesnt let me use it as a Wall for my flow.

The second part cant be neglected, because it has a starting temperature and I cant resolve this problem with just removing it.

Thanx in advance!

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5 Replies Last Post Jun 6, 2012, 4:11 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jun 5, 2012, 10:17 a.m. EDT
Hi

if you define your solid as "Heat Transer in Solid" domain node, you can add a Wall with noslip or slip conditions, as you are using NITF with heat coming from the fluid, but as a separate wall node due to the positions of the nodes and the override feature of nodes farther down in the tree

--
Good luck
Ivar
Hi if you define your solid as "Heat Transer in Solid" domain node, you can add a Wall with noslip or slip conditions, as you are using NITF with heat coming from the fluid, but as a separate wall node due to the positions of the nodes and the override feature of nodes farther down in the tree -- Good luck Ivar
Igor Polushkin
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Posted: 1 decade ago Jun 5, 2012, 10:44 a.m. EDT
Hello Ivar,

Do you mean I have to exclude my solid plate out of "ntfl" and include it in "Heat transfer in solids"?

Then I will be able to use wall condition in NITF? Or in HTiS?

Thank you!
Hello Ivar, Do you mean I have to exclude my solid plate out of "ntfl" and include it in "Heat transfer in solids"? Then I will be able to use wall condition in NITF? Or in HTiS? Thank you!
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jun 5, 2012, 2:42 p.m. EDT
Hi

N,o what I'm saying is that when you open a NITF physics with fluid flow as heat source, you get a given number of Default nodes, you need to add a Heat Transfer in Solid domain node to define your "solid" part, then you can add a wall between the fluid and the solid.
But that is also what I see in your model, so I do not fully understand what your are missing

--
Good luck
Ivar
Hi N,o what I'm saying is that when you open a NITF physics with fluid flow as heat source, you get a given number of Default nodes, you need to add a Heat Transfer in Solid domain node to define your "solid" part, then you can add a wall between the fluid and the solid. But that is also what I see in your model, so I do not fully understand what your are missing -- Good luck Ivar
Igor Polushkin
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Posted: 1 decade ago Jun 6, 2012, 5:50 a.m. EDT
Hello Ivar,

what I`m missing is the definition of the wall for the solid part, if only I could use it somehow, that would be great. I had an idea about a small layer between the solid and liquid parts, so I could define the concact pair/identity pair, but I had problems with temperature. With this layer I lose my heat transfer.

Is it possible in Comsol to make something like that?

Thx in advance!
Hello Ivar, what I`m missing is the definition of the wall for the solid part, if only I could use it somehow, that would be great. I had an idea about a small layer between the solid and liquid parts, so I could define the concact pair/identity pair, but I had problems with temperature. With this layer I lose my heat transfer. Is it possible in Comsol to make something like that? Thx in advance!
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jun 6, 2012, 4:11 p.m. EDT
Hi

then use Assembly mode, this means that all boundary are dedoubled, and YOU the user must define all continuity pairs physics (one pair per physics). This allows you also normally to define a thermal resistive layer (or I was it this case that was announced for 4.3, I cannot remember just now) At least try it. But d not forget to link all physics at the identity boundary

--
Good luck
Ivar
Hi then use Assembly mode, this means that all boundary are dedoubled, and YOU the user must define all continuity pairs physics (one pair per physics). This allows you also normally to define a thermal resistive layer (or I was it this case that was announced for 4.3, I cannot remember just now) At least try it. But d not forget to link all physics at the identity boundary -- Good luck Ivar

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