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capturing small rise in temperature

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Hi,

I have a rectangular block where I have assigned a heat source (W/cm^3). My ambient temperature is 25 deg. First I assigned a high thermal load and recorded the peak temperature. Then I reduced it by factor of 10 and recorded the temperature again. After reducing it few times, I plotted the peak temperature. Initially, the temperature came down linearly then after a threshold , the peak temperature remained stuck at 25.1 deg.

This does not make scene. Is there a way I can increase the model sensitivity at extremely low thermal load.

Regards,
Susant

2 Replies Last Post 19.03.2014, 14:44 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 11.03.2014, 14:37 GMT-4
Hi Susant

Are you sure it's not just the round-off of the displayed values ?

anyhow 0.1/(273.15+25) (consider T in [K]) is only about <0.03% so it's not a "big error" I would say,
Have you checked the sensitivity to the relative tolerance for the solver ? try to lower it by a factor 10 or 100

Finally mesh size, and mesh sensitivity, but I suspect you have already a fine mesh compared to your problem's need

--
Good luck
Ivar
Hi Susant Are you sure it's not just the round-off of the displayed values ? anyhow 0.1/(273.15+25) (consider T in [K]) is only about

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Posted: 1 decade ago 19.03.2014, 14:44 GMT-4
Hi Ivar,

You are correct. It was the round-off displayed value. After I changed the number of significant digit, it was ok.

Regards,
Susant
Hi Ivar, You are correct. It was the round-off displayed value. After I changed the number of significant digit, it was ok. Regards, Susant

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