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-   -   no value changes during transient simulation (https://www.cfd-online.com/Forums/fluent/165090-no-value-changes-during-transient-simulation.html)

wsh January 9, 2016 12:29

no value changes during transient simulation
 
1 Attachment(s)
Dear CFD Online users,

I am working on simple 2d heat transfer and solidification model. Model contains two cell zones - layer of pcm material surrounding oil pan and oil pan itself. Steady analysis worked fine, but my goal is to examine how long does it takes for pcm to completly solidify and to see how temperature is distributed over time, so I'v changed mode to transient and set up some animation. Unfortunately, it seems like heat flow is stopped - I can't noticed any value change over time.

What am I doing wrong? Cas file in attachment.


https://www.virustotal.com/en/file/f...is/1452359733/

47 awtomat January 9, 2016 17:00

Im having same issue. Modelling simple 3d grow-box with several vents and do want see temperature distribution over time -steady analysis works, transient not, please help

wsh January 12, 2016 13:03

please someone help me :(

hwet January 13, 2016 09:51

not changing transient results mean the solution has reached a steady state. i see running wrong in that. transient results will at some time reach steady state as well.

imagine opening your rooms door, the temperature change inside the room is a transient process but will eventually reach steady state.

wsh January 13, 2016 11:13

Transient simulation approach steady state after ten 10-sec time steps? Dont think so. Moreover, temperaure at both cellzones doesnt change at all and its level is equal to initialization temperature (310 K for example). Temp at whole cell zones is constant, this is not steady state

LuckyTran January 13, 2016 15:46

Quote:

Originally Posted by wsh (Post 580818)
Transient simulation approach steady state after ten 10-sec time steps? Dont think so. Moreover, temperaure at both cellzones doesnt change at all and its level is equal to initialization temperature (310 K for example). Temp at whole cell zones is constant, this is not steady state

If you have two cell zones make sure you have interfaces between them.

wsh January 13, 2016 16:22

"Interface" between them is a wall type boundary condition. Actually 2 bc, because fluent automatically creates a shadow boundary condition - is that correct? I've set up a "coupled" condition.


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