COMSOL Forums: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/
Most recent forum messagesSun, 27 Apr 2014 02:38:15 +0000COMSOL Forums: Thermoelectric Effect - Adding the physicshttp://www.comsol.com/shared/images/logos/comsol_logo.gif
http://www.comsol.com/community/forums/general/thread/32340/
Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p117737
I think the only difference is that in 3.3b we use the features called generic feature, domain conidtion or boundrary condition instead of just feature as in the 3.3guide.<br />
I used domain condition for the domain contition but genereic feature for the other condtions, where i choosed boundary in the supported geometric entity levels but you could use boundrary condtition directly, it should be the same thing.<br />
<br />
Since the seebeck effect does not readily exist as a material parameter I have the material parameters deactivated and use user input instead as in the guide. Do not use material parameters in model mode but instead variables and for selected domains. <br />
<br />
The deactivated weak form equations 3 and 4 is never used since for real materials the seebeck effeckt is always much lower then the conductivity.<br />
<br />
I think the attached file will work in your version. It can be tricky to successfully get the interface to the physics area but i think its good to locate the physics builder manager from the view dropdown and press the register development files button in the upper right corner of the manager.Sun, 27 Apr 2014 02:38:15 +000032340.1398566295.117737Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p117714
Hi Jonatan,<br />
Thanks for answering the question. I was using the example model, just combined T and V. But now I'm trying to build up the physics builder. But the guide is for 4.3 and I'm using 4.3b. There are several difference and it's not working. Could you share your physics builder file? <br />
Thanks a lot. <br />
Junce <br />
<br />
<div class="quote"><br />
<br />
Are you using the physics builder guide method?<br />
<br />
To meassure at boundrary, create a boundrary probe and use the insert or replace button in the expression section and find your identifier.Jx Jy or Jz from the drop down tree, choose your used physics then current density. To get current, change the type in the probe setting section to Integral. I write the expressions in variables with aproriate names then export the results to tables through global variable probes to get tables with nice headers.<br />
</div><br />
Sat, 26 Apr 2014 04:22:50 +000032340.1398486170.117714Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p117463
Are you using the physics builder guide method?<br />
<br />
To meassure at boundrary, create a boundrary probe and use the insert or replace button in the expression section and find your identifier.Jx Jy or Jz from the drop down tree, choose your used physics then current density. To get current, change the type in the probe setting section to Integral. I write the expressions in variables with aproriate names then export the results to tables through global variable probes to get tables with nice headers.Fri, 18 Apr 2014 18:40:15 +000032340.1397846415.117463Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p117437
Dear Jonatan, <br />
How did you get the current density? Now what I have is voltage but I need current density to calculate the power generation. <br />
Thanks! <br />
JunceFri, 18 Apr 2014 00:03:17 +000032340.1397779397.117437Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p117435
Dear Sergei, <br />
I have a question for the peltier test model: So you will get T and V for the result. How can I get the current (I) in the p and n legs to calculate the power? <br />
Thanks a lot! <br />
JunceThu, 17 Apr 2014 23:55:19 +000032340.1397778919.117435Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p109481
Yes, thank you<br />
<br />
Can I ask you what sw you use to write down equation in a fast way?Mon, 28 Oct 2013 22:08:23 +000032340.1382998103.109481Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p109479
Dario,<br />
<br />
Yes, this is the right equation. (Please correct my typo for the very last factor d(Vtest)/dy->d(Vtest/dz).<br />
<br />
Regards,<br />
SergeiMon, 28 Oct 2013 21:44:21 +000032340.1382996661.109479Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p109477
ok it works perfectly now<br />
<br />
forgive me for my ingenuityMon, 28 Oct 2013 21:40:17 +000032340.1382996417.109477Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p109475
Thank you,<br />
<br />
Yes I'm making the assumption that it is isotropic. So the right equation should simply be the one in the attached file?<br />
<br />
Mon, 28 Oct 2013 21:27:58 +000032340.1382995678.109475Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p109469
Dario,<br />
<br />
Seebeck weak contribution is placed for current balance, "emdc" interface, in your case.<br />
This term is shown in the attached image.<br />
<br />
There are couple issues with your weak contribution expression:<br />
1. According to Comsol sign convention, Seebeck weak term should be with “minus” sign.<br />
2. Seems you are modeling material with isotropic electric conductivity: sigma_xx=sigma_yy=sigma_zz=sigma. Then, all off-diagonal terms for electric conductivity should be zero. Yet, those terms (containing sigma_xy, sigma_xz, etc.) are non-zero in your expression. <br />
<br />
Regards,<br />
Sergei<br />
Mon, 28 Oct 2013 20:14:24 +000032340.1382991264.109469Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p109463
Dear Sergei I'm afraid that I need again your help.<br />
I'm trying to introduce the the Seebeck effect in the 3D model, my equation is the following one:<br />
dVol_emdc*(S*sigma)*((TSx_htgh+TSy_htgh+TSz_htgh)*test(Ex_emdc)+ (TSx_htgh+TSy_htgh+TSz_htgh)*test(Ey_emdc)+(TSx_htgh+TSy_htgh+TSz_htgh)*test(Ez_emdc))<br />
<br />
this equation is accepted by Comsol (not in red)<br />
<br />
I put at 273 K one end of the leg and at 473 the other end, one end is grounded, the other is at a floating potential V.<br />
<br />
When solving there is no voltage generation and all the leg is at 0V <br />
<br />
for the Peltier effect the model works if I put the respective equation in the field "dweack"<br />
<br />
where It is wrong?<br />
where is better to put the equation for the Seebeck?<br />
<br />
Thank you<br />
<br />
DarioMon, 28 Oct 2013 18:45:11 +000032340.1382985911.109463Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p109339
Hi Sergei,<br />
<br />
Thanks. In my application, I want to run heat transfer model in steady state and TEC model in transient mode to see change in temperature field after TEC is activated.<br />
<br />
Regards,<br />
SusantThu, 24 Oct 2013 20:08:05 +000032340.1382645285.109339Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p109334
Thank you sergei.<br />
<br />
Now i'll try to introduce also the generation effect in the 3D modelThu, 24 Oct 2013 18:21:36 +000032340.1382638896.109334Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p109111
Susant,<br />
<br />
It should work without any modifications in the weak contribution node. Just replace Stationary Step by Time Dependent Step. Then click Heat Transfer (ht) root node and make sure that Equation form is selected as “Time dependent”. Then click Electric Currents (ht) root node and make sure that Equation form is selected as “Stationary” (assuming that you are solving AC case).<br />
<br />
Regards,<br />
Sergei<br />
Fri, 18 Oct 2013 22:47:31 +000032340.1382136451.109111Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p109108
Hi Sergei,<br />
<br />
This is with reference to your model, Is there any modification to be done to the model if I want to do time dependent analysis instead of steady state?<br />
<br />
Regards,<br />
SusantFri, 18 Oct 2013 22:12:02 +000032340.1382134322.109108Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p108936
<div class="quote"><br />
Thank you again Sergei, can you tell me if this equation is good for a 2d axial symmetry domain?<br />
<br />
dVol_htgh*(S*T)*(Jr_emdc*test(TSr_htgh)+Jz_emdc*test(TSz_htgh)) <br />
<br />
<br />
dario<br />
</div><br />
<br />
Dario,<br />
<br />
Equation seems OK for 2D axial symmetry.<br />
<br />
Regards,<br />
Sergei<br />
Mon, 14 Oct 2013 20:58:23 +000032340.1381784303.108936Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p108918
Thank you again Sergei, can you tell me if this equation is good for a 2d axial symmetry domain?<br />
<br />
dVol_htgh*(S*T)*(Jr_emdc*test(TSr_htgh)+Jz_emdc*test(TSz_htgh)) <br />
<br />
<br />
darioMon, 14 Oct 2013 14:02:27 +000032340.1381759347.108918Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p108876
<div class="quote"><br />
ok thank you so much!<br />
Therefore also in 2D axial symmetry I don't need to do so?<br />
<br />
You believe that this equation is good as weak term for a 3D model?<br />
dVol_htgh*(S*T)*(-Jx_emdc*test(TSx_htgh)-Jy_emdc*test(TSy_htgh)-Jz_emdc*test(TSz_htgh)) <br />
0<br />
</div><br />
<br />
Dario,<br />
<br />
1. No, 2D plane and 2D axial symmetry are different. Multiplier dVol is Jacobian of coordinate transformation. In 2D plane geometry it reduces to 1 and in 2D axial symmetry case it reduces to 2*pi*r.<br />
<br />
I think, confusion here is due to different notations in 3.5 and 4.3. As far as I remember, in 3.5 multiplier dVol is always present in weak form notation (it was a while ago I use 3.5, though).<br />
<br />
<br />
2. I believe, your weak term is OK for 3D model in version 3.5a.<br />
<br />
Regards,<br />
Sergei<br />
Fri, 11 Oct 2013 16:13:33 +000032340.1381508013.108876Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p108865
ok thank you so much!<br />
Therefore also in 2D axial symmetry I don't need to do so?<br />
<br />
You believe that this equation is good as weak term for a 3D model?<br />
dVol_htgh*(S*T)*(-Jx_emdc*test(TSx_htgh)-Jy_emdc*test(TSy_htgh)-Jz_emdc*test(TSz_htgh)) <br />
0<br />
<br />
Fri, 11 Oct 2013 12:51:18 +000032340.1381495878.108865Re: Thermoelectric Effect - Adding the physics
http://www.comsol.com/community/forums/general/thread/32340/#p108856
<div class="quote"><br />
Dear Sergei,<br />
<br />
I'd like to ask you some questions:<br />
<br />
1)why in the 2D model you gave me you write:<br />
(-k_ht*Tx+P*Jx_dc)*test(Tx)+(-k_ht*Ty+P*Jy_dc)*test(Ty) without volume integration?<br />
<br />
2)where you have declared "P" ?<br />
<br />
Attached you find my 2D axial symmetric model, there I can find only a heat release at one junction but no heat absorption at the other. Can you explain me where I am wrong and why?<br />
<br />
Note that my file is more than 10 MB so I was forced to split it in 3 parts with winrar. Also i was forced to rename *.rar files as *.mph files so you have to rename the files in *.rar (otherwise the forum does not allow me to attach)<br />
<br />
Hope this is not too boring for you...<br />
<br />
Thank you soo much!<br />
</div><br />
<br />
Dario,<br />
<br />
1. I didn’t include volume integration because out-of-plane thickness was assumed to be one in that particular 2D example.<br />
<br />
2. Peltier coefficient “P” is defined under Model Variables on the domains level.<br />
<br />
3. I was not able to open your *.rar files.<br />
<br />
Regards,<br />
Sergei<br />
Thu, 10 Oct 2013 23:59:26 +000032340.1381449566.108856