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In joule heating ,how to compute the resistance of a body?

Posted Mar 28, 2013, 5:07 a.m. EDT Low-Frequency Electromagnetics, Heat Transfer & Phase Change Version 4.3 3 Replies

Yu Haiqun
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In joule heating ,how to compute the resistance of a body? can you tell me the formula? such as voltage is V, the symble of current is what and the symble of resistance is what in comsol? Thanks a lot!
3 Replies Last Post Mar 30, 2013, 3:50 a.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 28, 2013, 4:40 p.m. EDT
Hi

if you impose the voltage, you can get the current by integrating the current density over the flux area. Then as U= R*I => R = U/I you calculate the resistance

If you have selected the lumped ports / terminal nodes, COMSOL creates automatically variables for "lumped" voltage, current and resistance / impedance, so you do not need to define all the integrations / equations ...

--
Good luck
Ivar
Hi if you impose the voltage, you can get the current by integrating the current density over the flux area. Then as U= R*I => R = U/I you calculate the resistance If you have selected the lumped ports / terminal nodes, COMSOL creates automatically variables for "lumped" voltage, current and resistance / impedance, so you do not need to define all the integrations / equations ... -- Good luck Ivar
Yu Haiqun
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Posted: 1 decade ago Mar 30, 2013, 1:57 a.m. EDT
Thanks! It worked and converged, but I still can't get the value,How to display the variable value?Thanks!
Thanks! It worked and converged, but I still can't get the value,How to display the variable value?Thanks!
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 30, 2013, 3:50 a.m. EDT
Hi

you need to calcualte it from the Results derived values ... y getting the voltage divided by the integration of the current density => gives ou the average resisitance

--
Good luck
Ivar
Hi you need to calcualte it from the Results derived values ... y getting the voltage divided by the integration of the current density => gives ou the average resisitance -- Good luck Ivar

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