thermal boundary condition on an interface between a solid and a fluid

ajdad · February 24, 2015, 12:05

Hi,
I am modeling an interface between a fluid and solid and in ANSYS FLUENT I get a wall and its shadow. I want to specify a heat flux on the wall but it looks like when I do that the heat flux is not conducted to the other wall. ???
please, help me

...

LuckyTran · February 25, 2015, 17:52

Check to make sure the thermal boundary condition on the other wall and make sure it is the coupled condition. I think by default it's 0 heat flux.

ajdad · February 25, 2015, 18:29

thank you LuckyTran. but in ansys fluent, we can not choose the two options at the same time: coupling the two faces and impose a boundary condition :-(

jsm · February 26, 2015, 16:28

Hi,

Once you select heat flux or temperature option instead of coupled, there won't be any heat transfer between these walls. You are decoupling the walls.

Why you want to fix the temperature in the wall of inside domain? I don't understand the specific reason for this question.

There are many ways we can model this.

1. Remove solid and apply heat flux on the wall directly
2. Separate one layer element from solid nearer to the fluid and define as another solid and give the source term.
3. Use shell conduction option in the wall boundary condition and define the heat generation.

Select the one which is more suitable for your simulation definiton.

ajdad · February 26, 2015, 21:44

thank you mr jsm for your response. ok, if I want to use 3rd choices:
"Use shell conduction option in the wall boundary condition and define the heat generation."

How to convert a thermal power w/m^2 ==> W/m^3 ???

jsm · February 28, 2015, 10:20

It is difficult to answer your question. Usually, We have energy in Watts and that is the input as heat flux (W/m2) or energy source (W/m3).

wpdeng · June 5, 2015, 04:41

Hi,everybody. I have a question about heat flux: how can i get the heat flux of a line?

February 24, 2015, 12:05	thermal boundary condition on an interface between a solid and a fluid	#1
ajdad New Member ajdad Join Date: Feb 2015 Posts: 5 Rep Power: 11	Hi, I am modeling an interface between a fluid and solid and in ANSYS FLUENT I get a wall and its shadow. I want to specify a heat flux on the wall but it looks like when I do that the heat flux is not conducted to the other wall. ??? please, help me ...

February 26, 2015, 16:28		#4
jsm Senior Member JSM Join Date: Mar 2009 Location: India Posts: 192 Rep Power: 20	Hi, Once you select heat flux or temperature option instead of coupled, there won't be any heat transfer between these walls. You are decoupling the walls. Why you want to fix the temperature in the wall of inside domain? I don't understand the specific reason for this question. There are many ways we can model this. 1. Remove solid and apply heat flux on the wall directly 2. Separate one layer element from solid nearer to the fluid and define as another solid and give the source term. 3. Use shell conduction option in the wall boundary condition and define the heat generation. Select the one which is more suitable for your simulation definiton. __________________ With regards, JSM

February 28, 2015, 10:20		#6
jsm Senior Member JSM Join Date: Mar 2009 Location: India Posts: 192 Rep Power: 20	It is difficult to answer your question. Usually, We have energy in Watts and that is the input as heat flux (W/m2) or energy source (W/m3). __________________ With regards, JSM

June 5, 2015, 04:41	i have a question	#7
wpdeng New Member DENG Weriping Join Date: Jun 2015 Posts: 16 Rep Power: 10	Hi,everybody. I have a question about heat flux: how can i get the heat flux of a line?

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February 25, 2015, 17:52		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,668 Rep Power: 65	Check to make sure the thermal boundary condition on the other wall and make sure it is the coupled condition. I think by default it's 0 heat flux.

February 25, 2015, 18:29		#3
ajdad New Member ajdad Join Date: Feb 2015 Posts: 5 Rep Power: 11	thank you LuckyTran. but in ansys fluent, we can not choose the two options at the same time: coupling the two faces and impose a boundary condition :-(

February 26, 2015, 21:44		#5
ajdad New Member ajdad Join Date: Feb 2015 Posts: 5 Rep Power: 11	thank you mr jsm for your response. ok, if I want to use 3rd choices: "Use shell conduction option in the wall boundary condition and define the heat generation." How to convert a thermal power w/m^2 ==> W/m^3 ???