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-   -   Conjugate heat transfer (http://www.cfd-online.com/Forums/fluent/112933-conjugate-heat-transfer.html)

 achal February 8, 2013 01:40

Conjugate heat transfer

Problem Description : An iron brick is to be cooled by the use of
water jet, this would include convection from the top surface of brick
and conduction within the brick.
Is that what we call a conjugate heat transfer ?
Can it modelled with out the use of UDF ?
How do I model this, because there is no temperature change observed in the brick?
Any sort of help would highly be appreciated.

Thanks And Regards

Achal

 hellorishi February 12, 2013 08:08

Hi Achal,

Yes, this would be called CHT problem.
You would need to give a initial temperature to the brick. If there is a water jet cooling the brick, the temperature of iron brick is bound to change. After some "x" seconds it is likely to attain temperature of impending water jet (unless this brick is getting active heat from some other source).

UDF would not be essential.
Which software are you looking at for this kind of modeling?

Cheers
/R

 achal February 16, 2013 04:40

No, the brick is not getting any heat energy.
I used patch to initialise the temperature the brick.
Using steady state solver , yes, the temperature of brick became that of jet.
Using unsteady state, even if i select 1-2 seconds, it shows the temperature.
Do you think this to correct ?

Another question.

How can I be sure that heat conduction is happening inside the brick ?
I am not able to get a temperature profile of a cross section

I am using Fluent pacakge.

 hellorishi February 16, 2013 11:17

I am not sure if I understand what you said about about unsteady state and temperature.

What do you see if your take a cross section? It might be good to check if there are volume elements inside the brick. Depending on the meshing technique used, it is possible that there are no volume elements inside the brick.

 achal February 16, 2013 12:24

I need to know how much time does it take for the brick to reach room temperature, therefore I need unsteady state solver settings. Am i correct ?

I am sure there is volume meshing inside the brick, that is not an issue.

 achal February 16, 2013 12:26

I also need to get the temperature profile of a surface which is at the centre of brick, how can i do that ?

 hellorishi February 17, 2013 12:03

ya you are right that unsteady analysis is required to find time to cool the brick. It is kindof tough to guess whats going on without actually looking at the case. I am guessing it post-processing issue...

 achal February 17, 2013 12:51

have you worked on such a case ?
Also, I would love to share the case file with you; may I have your email address ?

 duri February 18, 2013 08:26

I think your wall thermal boundary condition is wrong. Use coupled boundary condition at the fluid solid interface wall.

 achal February 18, 2013 09:34

Hi

I have used coupled boundary condition on the interface.

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