Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Time dependent heat source on a surface

Please login with a confirmed email address before reporting spam

Hi,

I´d like to solve a simple problem but I came across issues. My time dependent heat source isn´t simulated correctly.

I´m simulating a wall with two layers with different external temperatures on the different sufaces. On the colder surface I´m adding a heat source on the surface (~60 [W/m²]). This heat source should be active when the wall (~35 cm thick) is more or less in a steady state and from there a heating duration of 8 [h] is planned.

For the heat source I´ve tried different definitions:

if(t < 576000,0,if(t > 604800,0,60)) 60rect1 where rect1 is a rectangular window 60pw1 where pw1 is a piecewise function with the conditions

From To Value 0 576000 0 160 h 576000 604800 1 160 h - 168 h 604800 800000 0 168 h - end of the simulation

Sometimes the animation player shows, that my source is neglected. The problem is sometimes solved by changing the time step control from "free" to "intermediate" and using adaptive mesh control.

The problem with the simulation is that the heat flux in X-direction is way smaller than it should be on the surface as well as the time when the heat source is active doesn´t fit. In the attached graph the error is more easy to be seen.

I apprechiate all help and every tip that could lead to a solution.

Best regards

Sebastian



0 Replies Last Post 2018年1月18日 GMT-5 08:09
COMSOL Moderator

Hello Sebastian M

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.