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At higher temperature.. cant solve the equaitons
Posted 03.07.2012, 09:59 GMT-4 Heat Transfer & Phase Change Version 4.2a 2 Replies
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Hi,
I am applying Joule heating in a time-dependent model, I input a constant current to a terminal and grounded the other. I set the initial value of temperature of 1673K for the whole body. When I am running the simulation, it is showing no progress.
But if I take the initial temperature to be aroung 1273K, , its giving me result.
Why is it showing problem at higher temperatures???
(PS: i set the time of 100sec with a jump of 0.1 second
and input all the properties of the material as a function of temperature---> so is it because at the high temperature some properties showing negative values, which were not supposed to be negative??????????)
Thanks in advance :) :)
I am applying Joule heating in a time-dependent model, I input a constant current to a terminal and grounded the other. I set the initial value of temperature of 1673K for the whole body. When I am running the simulation, it is showing no progress.
But if I take the initial temperature to be aroung 1273K, , its giving me result.
Why is it showing problem at higher temperatures???
(PS: i set the time of 100sec with a jump of 0.1 second
and input all the properties of the material as a function of temperature---> so is it because at the high temperature some properties showing negative values, which were not supposed to be negative??????????)
Thanks in advance :) :)
2 Replies Last Post 04.07.2012, 08:56 GMT-4
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Posted:
1 decade ago
Hi
check your material properties too, to be shure they are defined for these large T values, the curves might saturated or interpolated strangely
--
Good luck
Ivar
check your material properties too, to be shure they are defined for these large T values, the curves might saturated or interpolated strangely
--
Good luck
Ivar
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Posted:
1 decade ago
HI Ivar,
Thanks for your reply. I was thinking the same about abnormal behavior of properties at higher temp. and I tried too various combination of time and temperatures, and I find out that for higher value of either time, or temperature or both, but the comsol stuck at 79%.
However results are seen when
1) i use for 75 sec but not for 100 sec.
2) initial temperature below 1273K
3) and with both t and T high. (obviously not)
Could you please help me.... where is the problem? What i gonna do, i cant find anything to work out?
(PS: A Day before it was working, at 1273K and for 100 sec, until I changed one value of resistivity)
Pleaaaaaaaseeeeee help!!!
and thanks in advance!! :) :)
Thanks for your reply. I was thinking the same about abnormal behavior of properties at higher temp. and I tried too various combination of time and temperatures, and I find out that for higher value of either time, or temperature or both, but the comsol stuck at 79%.
However results are seen when
1) i use for 75 sec but not for 100 sec.
2) initial temperature below 1273K
3) and with both t and T high. (obviously not)
Could you please help me.... where is the problem? What i gonna do, i cant find anything to work out?
(PS: A Day before it was working, at 1273K and for 100 sec, until I changed one value of resistivity)
Pleaaaaaaaseeeeee help!!!
and thanks in advance!! :) :)