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How to justify the internal heat generation in comsol???

Posted Dec 29, 2011, 3:08 a.m. EST Heat Transfer & Phase Change Version 4.3a 7 Replies

shhtr hthas
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hi every one,

i am using comsol 4.1. i want to give a internal heat generation on rectangle..how can justify internal heat generation in comsol


any one help me??

thanking you,
parma
7 Replies Last Post Nov 14, 2012, 2:26 p.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Dec 29, 2011, 11:59 a.m. EST
Hi

try to add a "HT - right click - Domain Heat Source" to your model (it's in my 4.2a at least ;)

--
Good luck
Ivar
Hi try to add a "HT - right click - Domain Heat Source" to your model (it's in my 4.2a at least ;) -- Good luck Ivar
shhtr hthas
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Posted: 1 decade ago Jan 3, 2012, 4:12 a.m. EST
Hi,

i am using comsol 4.1. i have done one internal heat generation problem. i used Domains heat source menu for internal heat generation. now i want to vary the internal heat generation values. how can vary this value in comsol..it's possible or not....

can you help me???

Thanking you,
parma
Hi, i am using comsol 4.1. i have done one internal heat generation problem. i used Domains heat source menu for internal heat generation. now i want to vary the internal heat generation values. how can vary this value in comsol..it's possible or not.... can you help me??? Thanking you, parma
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jan 3, 2012, 5:37 a.m. EST
Hi

I'm not sure how it was back in 4.1 (everything was not fully implemented) but for HT I suppose its close to my 4.2a, you enter your expression (either with a time variable explicitly or a parameter sweep value to change your heat flux value). In COMSOL almost all fields accept equations, not only constant values

--
Good luck
Ivar
Hi I'm not sure how it was back in 4.1 (everything was not fully implemented) but for HT I suppose its close to my 4.2a, you enter your expression (either with a time variable explicitly or a parameter sweep value to change your heat flux value). In COMSOL almost all fields accept equations, not only constant values -- Good luck Ivar
Robert Jansson
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Posted: 1 decade ago Nov 13, 2012, 2:01 a.m. EST
Hi!
I do need a way to add internal heat and controol the heat release rate and the added total energy?
I.e. turn on internal heat generation at one temperature, controol the reelease rate and turn of when the fuel is consumed.
Is there a way to do this in Comsol?
If not is there any Matlab subroutine to perform such operations.

BR
Hi! I do need a way to add internal heat and controol the heat release rate and the added total energy? I.e. turn on internal heat generation at one temperature, controol the reelease rate and turn of when the fuel is consumed. Is there a way to do this in Comsol? If not is there any Matlab subroutine to perform such operations. BR
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Nov 13, 2012, 2:41 p.m. EST
Hi

have you checed the example of the PID controller, and the thermal control example in the model library (at least there were there for previous versions, if ot check the web site model gallery, this should help you on your way

--
Good luck
Ivar
Hi have you checed the example of the PID controller, and the thermal control example in the model library (at least there were there for previous versions, if ot check the web site model gallery, this should help you on your way -- Good luck Ivar
Robert Jansson
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Posted: 1 decade ago Nov 14, 2012, 6:54 a.m. EST
Hi.
Thankyou for your answer.
I was though more interested in if there is a way to controol the Q term in the heat transfer equation for solids.
To turn on internal Q at a given temperature, and at a given rate, and turn Q of when a given energy per volyme or per mass has been supplied.
To make this a one time operation to avoid repetition if temperature drops.
Not a phase shift that can be reversed, more like a one time combustion and possible mass loss.
Cp, k, etc. can be made temperature dependant.. But I dont know how to manipulate the mass and Q..

BR
Hans
Hi. Thankyou for your answer. I was though more interested in if there is a way to controol the Q term in the heat transfer equation for solids. To turn on internal Q at a given temperature, and at a given rate, and turn Q of when a given energy per volyme or per mass has been supplied. To make this a one time operation to avoid repetition if temperature drops. Not a phase shift that can be reversed, more like a one time combustion and possible mass loss. Cp, k, etc. can be made temperature dependant.. But I dont know how to manipulate the mass and Q.. BR Hans
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Nov 14, 2012, 2:26 p.m. EST
Hi

by making a new global variale or local field variable and define it (somewhat like the PID controller example)

But you can also give it a sinus or any other function, also periodic, but be sure your BC variation is continuous so the solver might derive a Jacobian

--
Good luck
Ivar
Hi by making a new global variale or local field variable and define it (somewhat like the PID controller example) But you can also give it a sinus or any other function, also periodic, but be sure your BC variation is continuous so the solver might derive a Jacobian -- Good luck Ivar

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