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-   -   how to use contact resistance model in floEFD (http://www.cfd-online.com/Forums/floefd-floworks-flotherm/90375-how-use-contact-resistance-model-floefd.html)

eggliang July 8, 2011 03:53

how to use contact resistance model in floEFD
 
I am tring to learn how to use contact resistance in floEFD software. I have done several cases to verify if this model works. but the result makes me a little bit disappointed. I applied the contact resistance between two contacting surfaces, but from the result, there seems to be no temperature drop btw these two surface. thus, it looks unbelivable.

is there any guys have experence on this? tell me how set this contact resistance to make it work..

any feedback is pretty appreciated...

GeneG July 15, 2011 14:53

Select contact resistant surface and assign : User Defined → eGRAF: Spreadershield HT-1205
(Th. Res. = 3.2e-5 C^2/W) as an example

eggliang July 21, 2011 01:31

great.

I re-do the simulation with a much more simple model and applied the contact resistance value to it. the result told that this resistance did work now. interesting results...

but previously i applied this resistance in my LED LAMP model btw two solid contacting surface, no temperature found..

Boris_M August 1, 2011 08:07

Hi eggliang,
have you tried it again in the more complex model? Did it work now?
If not please send the model to the support as they can check if there is any other issue that prevents it to work of if there might be a bug of some kind.
Usually if it works in general on a simple case then it's related to the geometry as the more complex case could contain a more complex geometry that could cause this issue for some reason.
I've seen cases where the geometry looks just perfect on the screen but something is bad in the CAD definition.

Regards,
Boris

eggliang August 5, 2011 00:36

dear Boris

sorry, I have not studies the case of more complex geometry for busing working recently. anyway, I think the contact resistance is a useful function designed for thermal designers. I don't know if you have some progress on this issue?:p


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