Menu

Discussion Forum

New Discussion
查找

Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

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.

How to control temperature ramp up/down time?

Posted 2011年9月1日 GMT-4 17:51 Heat Transfer & Phase Change, Modeling Tools & Definitions, Parameters, Variables, & Functions, Structural Mechanics Version 4.2 2 Replies

Wenjun Jiang
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hello,

I'm new in COMSOL. Currently I'm trying to simulate the stress on SiO2 thin film on silicon wafer based on the temperature ramp up/down from furnace.

I'm currently using time-dependent Heat Transfer module together with Structural Mechanics module to conduct the simulation, but I'm unable to find any place where I can specify the starting / ending temperature as well as the linear temperature ramp time. Can I set a parameter such as $time for time-dependence?

Can anyone give me some suggestion?

Thanks,

Albert
2 Replies Last Post 2011年9月2日 GMT-4 15:38
Edgar Kaiser
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2011年9月2日 GMT-4 03:39
Hi,

you can use COMSIOLs time variable 't' to define a time-dependent expression for the heated (cooled) boundaries or domains.

Cheers
Edgar
Hi, you can use COMSIOLs time variable 't' to define a time-dependent expression for the heated (cooled) boundaries or domains. Cheers Edgar
Wenjun Jiang
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2011年9月2日 GMT-4 15:38
Thanks. Here is the problem:

boundary 1: symmetry
--------------------------------------------------
boundary 2: boundary not set |
---------------------- furnace with air |
Silicon wafer | boundary 3||||||| boundary 6
---------------------- furnace with air |
boundary 4: boundary not set |
--------------------------------------------------
boundary 5: symmetry

Boundaries 2-4 form the silicon wafer region, while boundaries 1,5,6 form the surrounding furnace region containing air. I want the boundaries 6 to linearly ramp the temperature from T_start to T_end.

Now I'm using Heat Transfer module, with Initial Values1 of both domains (silicon and air) set to be T_start. Then I choose Temperature1 to boundary6, with ramping temperature T0=T_start+ramp_rate*t. Also I set Symmetry1 to boundaries 1&5.

However, I don't know how to set the Surface-to-Surface Radiation part. I chose boundaries 3&6 together, with Radiation direction to be Opacity controlled, Ambient temperature to be T_start, Surface emissivity to be 0.1, and Initial Values of Surface radiosity to be J=0 W/m^2. But when I ran the time dependent study, with Times to be set as "range(0, 1[min], (T_end-T_start)/ramp_rate", I got an error: "Radiation error: exactly one adjacent domain must be opaque. By default all the domains are transparent. Consider right-clicking the node where temperature is defined to add the Opaque subfeature."

By contrast, if I changed the Radiation direction to be either "Positive normal direction" or "Negative normal direction", with Ambient temperature to be Tamb=T_start + ramp_rate*t, I didn't get the error, but the 3D temperature plot showed no temperature at all: the final temperature is T_start everywhere !

Can anyone have any suggestion where is the error (I understand that I need to set up the opaque boundary condition, but I don't know how to set it up...), and how should I ramp up the temperature?

Thanks,

Albert
Thanks. Here is the problem: boundary 1: symmetry -------------------------------------------------- boundary 2: boundary not set | ---------------------- furnace with air | Silicon wafer | boundary 3||||||| boundary 6 ---------------------- furnace with air | boundary 4: boundary not set | -------------------------------------------------- boundary 5: symmetry Boundaries 2-4 form the silicon wafer region, while boundaries 1,5,6 form the surrounding furnace region containing air. I want the boundaries 6 to linearly ramp the temperature from T_start to T_end. Now I'm using Heat Transfer module, with Initial Values1 of both domains (silicon and air) set to be T_start. Then I choose Temperature1 to boundary6, with ramping temperature T0=T_start+ramp_rate*t. Also I set Symmetry1 to boundaries 1&5. However, I don't know how to set the Surface-to-Surface Radiation part. I chose boundaries 3&6 together, with Radiation direction to be Opacity controlled, Ambient temperature to be T_start, Surface emissivity to be 0.1, and Initial Values of Surface radiosity to be J=0 W/m^2. But when I ran the time dependent study, with Times to be set as "range(0, 1[min], (T_end-T_start)/ramp_rate", I got an error: "Radiation error: exactly one adjacent domain must be opaque. By default all the domains are transparent. Consider right-clicking the node where temperature is defined to add the Opaque subfeature." By contrast, if I changed the Radiation direction to be either "Positive normal direction" or "Negative normal direction", with Ambient temperature to be Tamb=T_start + ramp_rate*t, I didn't get the error, but the 3D temperature plot showed no temperature at all: the final temperature is T_start everywhere ! Can anyone have any suggestion where is the error (I understand that I need to set up the opaque boundary condition, but I don't know how to set it up...), and how should I ramp up the temperature? Thanks, Albert

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.

Suggested Content