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read temperture from conductor model and use it in equation
Posted 5 lug 2014, 17:45 GMT-4 Computational Fluid Dynamics (CFD) Version 4.3 1 Reply
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I am working with a 2D model. I have a circle which represents the cross-sectional area of an overhead line conductor. Around that circle, I draw a rectangle and gave fluid properties (air) to it. This rectangle simulates the convection cooling on the conductor as the conductor gains heat from solar radiation and Joule heating. For this model I use the conjucated heat transfer.
However, I would like to read and store the maximum temperature of the conductor (circle) in a variable named Tmax for example. I have defined Joule heating as a heat source on the conductor surface and is equal to (I^2)*R. The resistance of the conductor (R) varies with conductor temperature in a linear manner.
Let's say for example R=2Tmax+5. I want to store Tmax in a variable and use it in the expression of resistance R. Is there a way to store and use Tmax in R expression?
Also, how can I do this, in order to enable the value of resistance to change automatically as temperature of conductor Tmax varies?
However, I would like to read and store the maximum temperature of the conductor (circle) in a variable named Tmax for example. I have defined Joule heating as a heat source on the conductor surface and is equal to (I^2)*R. The resistance of the conductor (R) varies with conductor temperature in a linear manner.
Let's say for example R=2Tmax+5. I want to store Tmax in a variable and use it in the expression of resistance R. Is there a way to store and use Tmax in R expression?
Also, how can I do this, in order to enable the value of resistance to change automatically as temperature of conductor Tmax varies?
1 Reply Last Post 11 lug 2014, 08:03 GMT-4
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Posted:
1 decade ago
Hi,
you can define a coupling variable to read the maximum value on a specific geometric entity. You can add this variable in "Model>Definitions>Model Couplings>Maximum". By default it will be named "maxop1". You need to define in what area it shall evaluate a maximum. Now refer to that value by using the expression "maxop1(T)" to get e.g. the maximum value of "T" in that area. That expression can be used in any function or condition in your model.
--
Hope that helps!
Best regards,
Erik
*********************
Erik Bornhöft
Senior Technical Sales Engineer
COMSOL Multiphysics GmbH
Robert-Gernhardt-Platz 1
37073 Göttingen
Deutschland
Knowledge Base:
www.comsol.de/support/knowledgebase/browse/900/
COMSOL Blog:
www.comsol.de/blogs/
you can define a coupling variable to read the maximum value on a specific geometric entity. You can add this variable in "Model>Definitions>Model Couplings>Maximum". By default it will be named "maxop1". You need to define in what area it shall evaluate a maximum. Now refer to that value by using the expression "maxop1(T)" to get e.g. the maximum value of "T" in that area. That expression can be used in any function or condition in your model.
--
Hope that helps!
Best regards,
Erik
*********************
Erik Bornhöft
Senior Technical Sales Engineer
COMSOL Multiphysics GmbH
Robert-Gernhardt-Platz 1
37073 Göttingen
Deutschland
Knowledge Base:
www.comsol.de/support/knowledgebase/browse/900/
COMSOL Blog:
www.comsol.de/blogs/