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Unchanged Boundary Temperature ?
Posted Aug 9, 2017, 4:10 p.m. EDT Heat Transfer & Phase Change, Studies & Solvers Version 5.3 2 Replies
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Hi friends,
I built a simple 3-d model for Heat transfer in Building Materials. (File is attached)
I defined a piecewise function pw1(t)= 288.15 – t/480 for all 6 boundaries, a time-dependent function.(0<t<14400 sec)
Accordingly, Temperature in boundary must decrease to 258.15[K] or -15 celsius.
The initial temperature is 288.15[k], consistent with boundary condition in t=0.
But after time-dependent studying, the temperature in all points remain 288.15 unchanged.
It seems there is no heat transfer at all.
Thanks a lot in anticipation !
I built a simple 3-d model for Heat transfer in Building Materials. (File is attached)
I defined a piecewise function pw1(t)= 288.15 – t/480 for all 6 boundaries, a time-dependent function.(0<t<14400 sec)
Accordingly, Temperature in boundary must decrease to 258.15[K] or -15 celsius.
The initial temperature is 288.15[k], consistent with boundary condition in t=0.
But after time-dependent studying, the temperature in all points remain 288.15 unchanged.
It seems there is no heat transfer at all.
Thanks a lot in anticipation !
Attachments:
2 Replies Last Post Aug 10, 2017, 3:43 a.m. EDT
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Posted:
7 years ago
Hi Albert,
It looks like you turned off the only equation in the Study 1>Step 1 node. You unchecked the "Solve For" check box. Check it back on and you're back in business.
Best,
Jeff
PS: For these types of test models, you may want to use fewer time steps to speed things up.
It looks like you turned off the only equation in the Study 1>Step 1 node. You unchecked the "Solve For" check box. Check it back on and you're back in business.
Best,
Jeff
PS: For these types of test models, you may want to use fewer time steps to speed things up.
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Posted:
7 years ago
Dear Jeff,
Thanks a lot for your response.
I fixed it, and changed my temperature function so that the study time is reduced to 600 sec.
But the results seems not correct. The temperature in all points is equal to B.C. : 288.15 at t=0 and 258.15 at t=600 !
I added 3 other phyisics (Moisture transport, Solid Mechanics & Darcy's law) and one Multyphisics (Poroelasticity) and a node (Phase Change) to reach the final model, but the results remain unchanged.
TIP: I would like to couple Heat & Moisture, but I noticed that by adding "Phase Change", domain 1 under "Heat & Moisture" becomes "not applicable" and yields to Jacobian error.
I wait for any intelligent idea !
Thanks a lot for your response.
I fixed it, and changed my temperature function so that the study time is reduced to 600 sec.
But the results seems not correct. The temperature in all points is equal to B.C. : 288.15 at t=0 and 258.15 at t=600 !
I added 3 other phyisics (Moisture transport, Solid Mechanics & Darcy's law) and one Multyphisics (Poroelasticity) and a node (Phase Change) to reach the final model, but the results remain unchanged.
TIP: I would like to couple Heat & Moisture, but I noticed that by adding "Phase Change", domain 1 under "Heat & Moisture" becomes "not applicable" and yields to Jacobian error.
I wait for any intelligent idea !
Attachments: