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Heat tranfer module

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Hello,

I would like to ask something about a heat transfer module. I´m analyzing the heat dissipation in a battery, this battery has an aluminum layer ("L" shape) connected in one side and this layer is connected to a cold plate. The heat must flow only from this layer to the cold plate.
I´m having some problems because I´m assuming all the boundaries thermically insulated except the aluminum layer connected to the cold plate. The exact problem is that in the boundaries that I´m assuming thermally insulated, when I calculated the normal heat transfer through this boundary is not zero.
The other problem is that when I calculated the total flux flowing from the aluminum plate to the cold plate is not the heat generation that I have assume. For example: I have assumed a 3W generation in the cell and the total heat flowing to the cold plate is only 2W.

Do you know which one could be the problem? Could it be a problem with the mesh?

Thanks in advance.

A. Jenkins

2 Replies Last Post Jul 13, 2010, 3:31 a.m. EDT

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Posted: 1 decade ago Jul 12, 2010, 6:12 p.m. EDT
Ann,

Have you found a solution to this problem?

I am having similar difficulties. I assume you are calculating the heat transfer through the boundary with a surface integral in the Derived Values section? Did you use the "total normal heat flux" variable or a component of the total heat flux vector that is normal to your surface? Incredibly, I have found that the two give different results. The total normal heat flux gave better results with no heat flowing across insulated boundaries, while the other did.

I also have the problem where the heat flowing into an object in my simulation is not equal to the heat flowing out for a "stationary" solution.

I have tried a range of mesh sizes. It doesn't seem to fix this problem.
Ann, Have you found a solution to this problem? I am having similar difficulties. I assume you are calculating the heat transfer through the boundary with a surface integral in the Derived Values section? Did you use the "total normal heat flux" variable or a component of the total heat flux vector that is normal to your surface? Incredibly, I have found that the two give different results. The total normal heat flux gave better results with no heat flowing across insulated boundaries, while the other did. I also have the problem where the heat flowing into an object in my simulation is not equal to the heat flowing out for a "stationary" solution. I have tried a range of mesh sizes. It doesn't seem to fix this problem.

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Posted: 1 decade ago Jul 13, 2010, 3:31 a.m. EDT
I think, you really need to upload the (small) mph file.

I've tried to look into my crystal ball, but I can't see anything. :)
I think, you really need to upload the (small) mph file. I've tried to look into my crystal ball, but I can't see anything. :)

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