# Problem with conjugate heat transfer between 2 fluids

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 December 6, 2017, 09:16 Problem with conjugate heat transfer between 2 fluids #1 Member   Join Date: Apr 2017 Location: india Posts: 96 Rep Power: 9 I a new to FLUENT -so kindly help me out. PROBLEM WITH CONJUGATE HEAT TRANSFER BETWEEN 2 FLUIDS I have 3D-2 ZONE MODEL - a furnace part and a rectangular part inside it. Both are fluids but the the rectangular part is a porous MEDIUM. I combines the 2 parts (furnace part and a rectangular part) using form a new part in the geometry section- in order to get a good mesh continuity. Now in order to get heat transfer from the furnace part to the inside of the porous rectangular part what should the contact region between these two bodies be, should it be a 1. Interior furnace-rectangular which fluent automatically creates or 2. I should change it to wall and adjust the properties of the wall as such, as in wall case it becomes coupled and heat transfer is possible. 3. or like a solid-fluid interaction we should name the boundary wall in the furnace and rectangular section differently and combine it in mesh interface as coupled wall etc Kindly help me out- thanks in advance

 December 7, 2017, 08:06 #2 Member   Join Date: Apr 2017 Location: india Posts: 96 Rep Power: 9 Kindly reply..............................!!!!!!!!!!! someone

 December 7, 2017, 10:54 #3 Member   Ravindra Shende Join Date: Feb 2011 Location: Pune, India Posts: 45 Rep Power: 15 Can you give some sketch of the geometry indicating the solid and fluid parts? (also indicate boundary conditions)

 December 7, 2017, 12:32 #4 Member   Join Date: Apr 2017 Location: india Posts: 96 Rep Power: 9 PROBLEM WITH CONJUGATE HEAT TRANSFER BETWEEN 2 FLUIDS I have 3D-2 ZONE MODEL - a furnace part and a rectangular part inside it. Both are fluids but the bottom layer is the porous fluid layer. So what should be the contact region be .............by default interior will come etc. I combines the 2 parts (furnace part and a rectangular part) using form a new part in the geometry section- in order to get a good mesh continuity. Now in order to get heat transfer from the furnace part to the inside of the porous rectangular part what should the contact region between these two bodies be, should it be a 1. Interior furnace-rectangular which fluent automatically creates or 2. I should change it to wall and adjust the properties of the wall as such, as in wall case it becomes coupled and heat transfer is possible. 3. or like a solid-fluid interaction we should name the boundary wall in the furnace and rectangular section differently and combine it in mesh interface as coupled wall etc Kindly help me out- thanks in advance Last edited by sooraj546; December 7, 2017 at 13:40.

 December 8, 2017, 00:22 #5 Member   Join Date: Apr 2017 Location: india Posts: 96 Rep Power: 9 Kindly reply..............................!!!!!!!!!!! someone

December 12, 2017, 01:49
#6
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Ravindra Shende
Join Date: Feb 2011
Location: Pune, India
Posts: 45
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Quote:
 Originally Posted by sooraj546 Kindly reply..............................!!!!!!!!!!! someone

December 13, 2017, 09:10
#7
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Join Date: Apr 2017
Location: india
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I have 3D-2 ZONE MODEL - a furnace part and a rectangular part inside it. Both are fluids but the the rectangular part is a porous MEDIUM.

I combines the 2 parts (furnace part and a rectangular part) using form a new part in the geometry section- in order to get a good mesh continuity.

Now in order to get heat transfer from the furnace part to the inside of the porous rectangular part what should the contact region between these two bodies be, should it be a

1. Interior furnace-rectangular which fluent automatically creates or

2. I should change it to wall and adjust the properties of the wall as such, as in wall case it becomes coupled and heat transfer is possible.

3. or like a solid-fluid interaction we should name the boundary wall in the furnace and rectangular section differently and combine it in mesh interface as coupled wall etc

Kindly help me out- thanks in advance
Attached Images
 geometry.jpg (82.0 KB, 15 views)

 December 13, 2017, 11:06 #8 Member   Ravindra Shende Join Date: Feb 2011 Location: Pune, India Posts: 45 Rep Power: 15 I am assuming that there is no mass transfer between the two zones. In that case you have to create two zones in the mesh separated by a surface. The mesh on the common surface should also be common for both zones. This will cause Fluent to recognize the mesh as two zones separated by a wall. Now you can use 'coupled' boundary condition a the common surface which will allow heat transfer between the two zones but no mass transfer. In the two zones you can set one zone as fluid and the other as porous.

 December 13, 2017, 11:19 #9 Member   Join Date: Apr 2017 Location: india Posts: 96 Rep Power: 9 There is mass transfer from zone 1 to the inside of the porous medium and back as well sorry I forgot to mention that , kindly reply . Thanks a lot in advance But there is a problem if I do wall and coupled heat transfer is happening but sir wall is solid rt then mass transfer won’t work. So for this I have made 2 separate zone in geometry by frozen then formed new part then interior will come in between this 2 zones so mass transfer heat transfer can happen

 December 13, 2017, 11:31 #10 Member   Ravindra Shende Join Date: Feb 2011 Location: Pune, India Posts: 45 Rep Power: 15 Fluent allows you to define a zone as porous. No need to specify any special boundary condition at the interface. Just specify the properties of the porous zone. Here is the link: http://www.afs.enea.it/project/neptu...ug/node233.htm

 December 13, 2017, 11:54 #11 Member   Join Date: Apr 2017 Location: india Posts: 96 Rep Power: 9 so fluent is recognizing it an interior so what i am doing is absolutely fine ? and sir on more question.............................. sir- is mesh continuity important from zone one to porous zone for heat and mass trasnfer to happen? ----- even if mesh continuity is not there heat and mass transfer is happening...............so i am a bit confused .................kindly help? by mesh continuity i meant every nodes match at interface without any break

 December 13, 2017, 12:11 #12 Member   Ravindra Shende Join Date: Feb 2011 Location: Pune, India Posts: 45 Rep Power: 15 Yes, what you are doing is fine. I am not sure about mesh continuity thing. Is the mass transfer and heat transfer same in both the cases?

 December 13, 2017, 12:12 #13 Member   Join Date: Apr 2017 Location: india Posts: 96 Rep Power: 9 both case ?

December 13, 2017, 12:20
#14
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Ravindra Shende
Join Date: Feb 2011
Location: Pune, India
Posts: 45
Rep Power: 15
Quote:
 Originally Posted by sooraj546 both case ?
case 1: mesh with continuity
case 2: mesh without continuity

 December 13, 2017, 12:33 #15 Member   Join Date: Apr 2017 Location: india Posts: 96 Rep Power: 9 ok thanks a lot sir, Apart from obtaining mesh continuity by forming a new part in geometry in fluent,,,,,,,,,,,,,,,,,, is there any other method for obtaining mesh continuity

 March 7, 2018, 11:24 #16 New Member   sanjay sajeevan Join Date: Mar 2018 Posts: 10 Rep Power: 8 can you explain me how conjugate heat transfer can apply to a solid liquid interface please?