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how to control the temperature?

Posted Mar 5, 2013, 7:06 a.m. EST Low-Frequency Electromagnetics, Heat Transfer & Phase Change, Parameters, Variables, & Functions Version 4.0, Version 4.1 3 Replies

Zhifang Wang
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hello

after heating,then entering the cooling stage,when t=20s,i want to get the whole model T=20°C with temperature suddenly jumped
i know the way with ANSYS,but how to set with COMSOL

what should i do??

any help, thanks
3 Replies Last Post Jul 3, 2015, 6:22 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 6, 2013, 12:52 a.m. EST
Hi

How do you drive you temperature increase ? if its a heat source, you make a continuous function depending on "t" and you enter that to drive the heat source. But do ensure:
1) function is continuous, if possible derivable twice (use smoothed step or ramp or rect pulses from the model - definitions - functions list, or make your own.
2) you set the time stepping of your solver to intermediate or strict but do not leave "automatic"
3) you give time steps that cover the transition steps of your heat flux changes to correctly resolve them

--
Good luck
Ivar
Hi How do you drive you temperature increase ? if its a heat source, you make a continuous function depending on "t" and you enter that to drive the heat source. But do ensure: 1) function is continuous, if possible derivable twice (use smoothed step or ramp or rect pulses from the model - definitions - functions list, or make your own. 2) you set the time stepping of your solver to intermediate or strict but do not leave "automatic" 3) you give time steps that cover the transition steps of your heat flux changes to correctly resolve them -- Good luck Ivar
Zhifang Wang
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Posted: 1 decade ago Mar 9, 2013, 7:39 a.m. EST

thanks for your reply

with your advice,heat input can be controled.my question is that if need 60s to cool to the constant temperature

20degC with natural cooling after heating, but i want to cool 50s to reach 20degC with a order

how can i get ?

anything appreciate
thanks for your reply with your advice,heat input can be controled.my question is that if need 60s to cool to the constant temperature 20degC with natural cooling after heating, but i want to cool 50s to reach 20degC with a order how can i get ? anything appreciate
Cleber Pinheiro
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Posted: 9 years ago Jul 3, 2015, 6:22 p.m. EDT
Dear colleague,
I desire to implement a temperature control in my 3D MODEL. It consists the physics coupling between heat transfer and electric currents. The electric potential V is controlled such as the maximum temperature is below 100ºC. I tried to use the maxop1 operator with the syntax 14*(maxop1(T2)<100[degC]), where 14 is electrical potencial (14V), but it not is working: the temperature grows without control. I use the time-dependent solver relative tolerance equal to 1e-4 (to properly resolve the switching conditions).
I'm using COMSOL MULTIPHYSICS 4.0
I await help.
Best regards

Cleber da Silva Pinheiro
Dear colleague, I desire to implement a temperature control in my 3D MODEL. It consists the physics coupling between heat transfer and electric currents. The electric potential V is controlled such as the maximum temperature is below 100ºC. I tried to use the maxop1 operator with the syntax 14*(maxop1(T2)

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