Interface Heat Transfer

KyleA&M · October 4, 2013, 14:46

Hello fellow fluideers. This is my first time using interfaces and I've stumbled my way along but I thought I figured it out. I am creating interfaces from a fluid to a solid, and then that solid to another fluid region. I'll give you a brief summary of how I created my interface.

1.After importing my CAD assembly I thought it would automatically create contacts as I had that checked when I imported but it didn't, so after importing I went into the parts and set the contacts from region to region i wanted.

2. I then sent those parts to three separate regions and voilla, interfaces were created.

3. Generated meshes

4. I realized I needed to go into regions->Region1->interface and select which part surfaces I wanted to use, so i did that for the three regions.

The problem is when I run it there is no temperature transfer across the interfaces. I have a separate physics continua for each region and all of them have the coupled energy models.

I believe there are 2 possibilities why this isnt working.
1. I can go into the physics conditions of the interfaces and and under "user wall heat flux coefficient" I can set it to none and specified. Do I need to set it to specified? If so it asked for user wall heat flux coefficient A,B,C, and D... What do those mean? They all have different units, I think I may need to set one of them to be the "overall heat transmission coefficient" which i can get from here.
http://www.engineeringtoolbox.com/ov...nts-d_284.html

2. Heat transfer isn't working because the physics condition of the face used for the interface is set to adiabatic. I could set the face to convection but that needs me to set an ambient temperature and coefficient, which leads me to believe that it's for convection as if there was a region of air around the face, not convection across an interface.

I'm thinking its possibility 1 but I'm really not sure. Any advice or answers would be appreciated

Sorry if this was too long I figure its better to fill you in on my process and thoughts.

Kasey · October 7, 2013, 11:21

It depends on what your model is doing, the physics need will depend on what is actually happening. I'm guessing that neither of those should keep the energy transfer from happening across the interface. Did you re-generate the mesh after creating the interfaces in step 4?

KyleA&M · October 8, 2013, 11:05

No i didn't, I actually figured out my problem. The steel divider had only one face which included all of its surfaces, and the interfaces with both fluid regions were using that one steel face, so I split the faces up and assigned interfaces to their respective faces and it worked. Thanks for the reply.

October 4, 2013, 14:46	Interface Heat Transfer	#1
KyleA&M New Member Kyle McVay Join Date: Apr 2013 Posts: 8 Rep Power: 13	Hello fellow fluideers. This is my first time using interfaces and I've stumbled my way along but I thought I figured it out. I am creating interfaces from a fluid to a solid, and then that solid to another fluid region. I'll give you a brief summary of how I created my interface. 1.After importing my CAD assembly I thought it would automatically create contacts as I had that checked when I imported but it didn't, so after importing I went into the parts and set the contacts from region to region i wanted. 2. I then sent those parts to three separate regions and voilla, interfaces were created. 3. Generated meshes 4. I realized I needed to go into regions->Region1->interface and select which part surfaces I wanted to use, so i did that for the three regions. The problem is when I run it there is no temperature transfer across the interfaces. I have a separate physics continua for each region and all of them have the coupled energy models. I believe there are 2 possibilities why this isnt working. 1. I can go into the physics conditions of the interfaces and and under "user wall heat flux coefficient" I can set it to none and specified. Do I need to set it to specified? If so it asked for user wall heat flux coefficient A,B,C, and D... What do those mean? They all have different units, I think I may need to set one of them to be the "overall heat transmission coefficient" which i can get from here. http://www.engineeringtoolbox.com/ov...nts-d_284.html 2. Heat transfer isn't working because the physics condition of the face used for the interface is set to adiabatic. I could set the face to convection but that needs me to set an ambient temperature and coefficient, which leads me to believe that it's for convection as if there was a region of air around the face, not convection across an interface. I'm thinking its possibility 1 but I'm really not sure. Any advice or answers would be appreciated Sorry if this was too long I figure its better to fill you in on my process and thoughts.

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October 7, 2013, 11:21		#2
Kasey New Member kw Join Date: Oct 2011 Posts: 24 Rep Power: 14	It depends on what your model is doing, the physics need will depend on what is actually happening. I'm guessing that neither of those should keep the energy transfer from happening across the interface. Did you re-generate the mesh after creating the interfaces in step 4?

October 8, 2013, 11:05		#3
KyleA&M New Member Kyle McVay Join Date: Apr 2013 Posts: 8 Rep Power: 13	No i didn't, I actually figured out my problem. The steel divider had only one face which included all of its surfaces, and the interfaces with both fluid regions were using that one steel face, so I split the faces up and assigned interfaces to their respective faces and it worked. Thanks for the reply.