Thermal conductance 1

[nibola]

Hello everyone

I have two surfaces in contact with some heat going through them. I am using bonded contact. But the contact between both surfaces will not be perfect, so I would like to consider a 50% of the thermal conductance between them.

Is there any way I can do that?
In contact, advanced, there is the Thermal conductance value, which usually is Program Controlled. If I run the calculation like that, the temperature raises 0.8C.

So If I have 3W and the surface in contact is 94.95mm2, the coefficient should be about 40000W/m2C. So applying this number I should have the same result as with Program controlled and then I could apply half of this value. But using 40000W/m2C I don't have the same value as with program controlled, the temperature raises 1.6C

So, any idea?

Thank you very much

 

[nibola]

Hello everyone

I will answer to myself, in case someone is interested.

First of all, the increase of temperature should be done only in the contact and target surfaces, not in the main body (we can obtain these values in Solution, Insert, Probe, Temperature). So in my case, the raising of temperature is 0.0149Celsius (instead of 0.8C)

If thermal conductance value is program controlled, the program assigns a relatively high value (Value can be verified from "Solution Information" - Thermal contact conductance coef. TCC), which makes the contact perfectly thermal. In this case the temperature rise between the contact and target surfaces will be very low, almost negligible.

If we want to model a thermal contact which is not perfect, as the Program controlled value for thermal conductance is very high (to simulate perfect thermal contact), to make the contact imperfect, thermal conductance value has to be decreased by a large factor up to a point where a temperature rise is observed between contact and target surface (cutoff value for thermal conductance, obtained by trial and error).
If we do a graph between the increase of temperature between surfaces and the TCC, there is a value where we have an elbow and the temperature rises exponentially. This is the cut off value.
If we want to simulate a 50% of thermal conductance, that is the value we need to take as a reference.

Regards

 

[Kherszal9]

Nibola,

Thanks for posting your solution method, rather than just leaving the forum open. I am not currently having this issue, but its always appreciated and helpful to find completed solutions and methods like this!

Hopefully it will save someone from the same issue down the line.

~ Kherszal