Hi Everyone,
I have two simple questions that I have been unable to answer after trying to work on them for a week. Please help me:
1) I have a very simple model (which I have attached), I am passing a few Milli-amps through my geometry and observing how the material is heating up and seeing how two things in particular are affected: The thermal conductivity k and the electrical conductivity sigma. The material I am using is polysilicion from the model library in Comsol. Both sigma and K are temperature dependent; the thermal conductivity is producing a reasonable result. However, electrical conductivity is a constant through out the domain, even though the equation for sigma is temperature dependent. The changes in temperature are big enough that I should see a complicated profile of electrical conductivity rather than just a constant. As a a result, the resistance of a material is a constant throughout which I know from experiment is not true.
I have tried using my own equations for electrical conductivity but with no success. Can anyone please advise as to what could be going wrong? The attached model is simple enough that anybody should be able to look at it in a few minutes and tell me what I could be doing incorrectly.
2) I have heat transfer as one of my physics models and under heat source in that model, I have the option to use "electromagnetic power loss density (ec/cucn1)" (which I heard is similar to joule heating). Can any please tell me what cucn1 means or where I can find its definition?
Any, I repeat, any help would be tremendously appreciated.
-Ammar.
I have two simple questions that I have been unable to answer after trying to work on them for a week. Please help me:
1) I have a very simple model (which I have attached), I am passing a few Milli-amps through my geometry and observing how the material is heating up and seeing how two things in particular are affected: The thermal conductivity k and the electrical conductivity sigma. The material I am using is polysilicion from the model library in Comsol. Both sigma and K are temperature dependent; the thermal conductivity is producing a reasonable result. However, electrical conductivity is a constant through out the domain, even though the equation for sigma is temperature dependent. The changes in temperature are big enough that I should see a complicated profile of electrical conductivity rather than just a constant. As a a result, the resistance of a material is a constant throughout which I know from experiment is not true.
I have tried using my own equations for electrical conductivity but with no success. Can anyone please advise as to what could be going wrong? The attached model is simple enough that anybody should be able to look at it in a few minutes and tell me what I could be doing incorrectly.
2) I have heat transfer as one of my physics models and under heat source in that model, I have the option to use "electromagnetic power loss density (ec/cucn1)" (which I heard is similar to joule heating). Can any please tell me what cucn1 means or where I can find its definition?
Any, I repeat, any help would be tremendously appreciated.
-Ammar.