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Shoot-up Temperature by Heat Transfer in Solid

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Old   December 1, 2016, 06:15
Default Shoot-up Temperature by Heat Transfer in Solid
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Onur Özcan
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Hi all,

I am working on temperature distribution in 3D solid material by solving energy equation.

There is a fluid that is not flowing is contacted with regarding solid material.
That is why I have defined as solid instead fluid. Well, I have run in calculation solving all equations from the beginning (flow+turbulence+energy equation) (environmental air is available in medium, that is why flow is indispensable for model I have done).

Solid material temperature is patched 323.15 K

But solid material temperature has begun about 900K in first iteration and increased about 1175K. Its temperature has begun to drop in following 600 iterations. Now iteration :2000, its temperature still drops in ,(now its temperaute 1080K)

Why does temperaute shoot-up occur? It is a normal or not?

Kind Regards,
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Old   December 1, 2016, 07:47
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Quote:
Originally Posted by oozcan View Post
Hi all,

I am working on temperature distribution in 3D solid material by solving energy equation.

There is a fluid that is not flowing is contacted with regarding solid material.
That is why I have defined as solid instead fluid. Well, I have run in calculation solving all equations from the beginning (flow+turbulence+energy equation) (environmental air is available in medium, that is why flow is indispensable for model I have done).

Solid material temperature is patched 323.15 K

But solid material temperature has begun about 900K in first iteration and increased about 1175K. Its temperature has begun to drop in following 600 iterations. Now iteration :2000, its temperature still drops in ,(now its temperaute 1080K)

Why does temperaute shoot-up occur? It is a normal or not?

Kind Regards,
Just for clarification:
1) What i understood is you are modeling environment, and in that environment you have that solid body. Is this correct ?
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Old   December 1, 2016, 07:54
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Quote:
Originally Posted by Kushal Puri View Post
Just for clarification:
1) What i understood is you are modeling environment, and in that environment you have that solid body. Is this correct ?
No, no, man

I have a model having three bodies (made three bodies into a part )

One of them is air, the other ones are solid and fluid. But that fluid is not flowing and I am working on temperature distribution for 3d solid material.

fluid that is not flowing is defined as solid and its temperature is fixed as 1273.15 K
solid material temperature is patched 323.15K
Environmental air is cooling the solid material having not 1273,15 K

I have two inlet in enrovironmetal air domain and that enclosure boundary are given as outlet boundary conditions (pressure outlet). Actually it is not a system it is a control volume
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Old   December 1, 2016, 07:58
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Quote:
Originally Posted by oozcan View Post
No, no, man

I have a model having three bodies (made three bodies into a part )

One of them is air, the other ones are solid and fluid. But that fluid is not flowing and I am working on temperature distribution for 3d solid material.

fluid that is not flowing is defined as solid and its temperature is fixed as 1273.15 K
solid material temperature is patched 323.15K
Environmental air is cooling the solid material having not 1273,15 K

I have two inlet in enrovironmetal air domain and that enclosure boundary are given as outlet boundary conditions (pressure outlet). Actually it is not a system it is a control volume
But my question is if you model that fluid as solid then the heat transfer will be in conduction mode which has to be in convection mode.
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Old   December 1, 2016, 08:01
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Quote:
Originally Posted by Kushal Puri View Post
But my question is if you model that fluid as solid then the heat transfer will be in conduction mode which has to be in convection mode.
right ! then ?
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Old   December 1, 2016, 08:35
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Quote:
Originally Posted by Kushal Puri View Post
But my question is if you model that fluid as solid then the heat transfer will be in conduction mode which has to be in convection mode.
I am waiting for your comment or experience,
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Old   December 1, 2016, 08:48
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Quote:
Originally Posted by oozcan View Post
I am waiting for your comment or experience,
Can you explain the complete problem, so that we can find some good approach.
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Old   December 1, 2016, 09:40
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Quote:
Originally Posted by Kushal Puri View Post
Can you explain the complete problem, so that we can find some good approach.
attached screenshot help you what about geometry is,

the other screenshots are relevant to FLUENT. Issue is like I said above.
Attached Images
File Type: jpg 1.jpg (111.9 KB, 8 views)
File Type: jpg 2.jpg (124.4 KB, 6 views)
File Type: jpg 3.jpg (127.1 KB, 6 views)
File Type: jpg 4.jpg (130.7 KB, 6 views)
File Type: jpg Capture.JPG (146.3 KB, 5 views)
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Old   December 1, 2016, 10:02
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Quote:
Originally Posted by oozcan View Post
attached screenshot help you what about geometry is,

the other screenshots are relevant to FLUENT. Issue is like I said above.
This behavior is correct even though you are patching 325.15 in solid but your melting glass temperature is high and due to conduction it is doing so. Run it more and put one volume monitor-> volume average temperature in the solid zone so that we can have idea about how temperature is reducing. And of-course we need to run until unless temperature is constant.
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Old   December 6, 2016, 03:44
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Quote:
Originally Posted by Kushal Puri View Post
This behavior is correct even though you are patching 325.15 in solid but your melting glass temperature is high and due to conduction it is doing so. Run it more and put one volume monitor-> volume average temperature in the solid zone so that we can have idea about how temperature is reducing. And of-course we need to run until unless temperature is constant.
So, steady state has been reached and volume averaged tempeature is 1045K,it is really very high value.

I could not make coupled wall for two solid cell zones that interface together,previously.

Now, I have made coupled wall for two cell zones. (solid-solid interfaces of different materials)

mesh/modify-zones/slit-interior-between-diff-solids, maybe solid material cell zone temperature (volume averaged) will be below 1000K in this time. But still that value is very high again because of conduction heat transfer (?).

Well, you know fluid that is not flowing had been defined as solid. Probably, solid cell zone temperature (volume averaged) will be higher than I expected. (comparison to convection heat transfer)

What should I do?

Hint: I attached volume averaged temperature in previous post.(first screenshot)

That is time, avareged temperature doesnt exceed 1150K (because of conduction), now,its value reached 1050K then, its temperature still is to reduce. That's why as I write above, probably, its temperature will be 1000K in steady state
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