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-   -   Heat transfer coefficent for the coupled wall (http://www.cfd-online.com/Forums/fluent/68484-heat-transfer-coefficent-coupled-wall.html)

jing113cn September 22, 2009 04:15

Heat transfer coefficent for the coupled wall
 
I am trying to simulate a fluid-solid problem. At the interface between the fliud and solid, I want to set a the heat transfer coefficient. But in Fluent, there is no such option if i choose "coupled wall" boundary condition. So I set the wall thickness at the interface in order to get the right value of heat transfer coefficient.
The problem is, how to know that I set the right wall thickness, can I check the heat transfer coefficient in Fluent ?

timjm September 30, 2009 10:46

Did you try turning on the thermal model and specifying the heat transfer coefficient for the solid? This way you do not have to specify the thickness of your wall.

jing113cn October 1, 2009 03:10

In my problem, I had two adjacent materials, solid and fluid (like mold and liquid). The solid is not just a wall, it has thickness and I want to simulate its temperature field. So I use the "coupled wall "in Fluent. In such case, I can not specify the heat transfer coefficient for the solid.

Quote:

Originally Posted by timjm (Post 231000)
Did you try turning on the thermal model and specifying the heat transfer coefficient for the solid? This way you do not have to specify the thickness of your wall.


denizen October 1, 2009 03:33

you need not set htc. it calculates automaticaly on system of equations (navier-stokes, energy...)
you can check htc in post processor.

regards.

owais70 October 1, 2009 16:38

It is basically a conjugate heat transfer problem. Code solves the energy equation for both material (fluid and solid) together. Just make sure that you have good mesh resolution near the wall for correct/accurate heat transfer. Post processing should allow you to look at the heat transfer coefficient. Remember, heat transfer coefficient can be calculated in three different ways.

1. Based on reference temperature
2. Based on adjacent fluid temperature
3. Based on wall function.

I believe if you resolve near wall region well, you should be able to get accurate HTC values

wave11 February 24, 2010 04:12

i would like to know how to get the coupled boundary condition. it is not available under thermal.
also in gambit, i've already set the continuiity type to SOLID and FLUID respectively. but i couldnt get the shadow zone.
please enlighten me.
thanks in advance :)


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