Change Boundary Condition type during Transient simulation

Achille · November 27, 2020, 04:30

Hello,

I am asking for your help for a boundary condition problem in a 2D model. I have a pipe on which I would like to apply a temperature to one of the surfaces. However, after a while, I want to remove this boundary condition and let the heat flow freely through my pipe. It's a bit like heating an iron bar in a fire (I impose my temperature), then removing it from the heat (I remove my limit condition) to see how the surface temperatures evolve.

(I know that it is possible to impose a temperature and make it vary over time thanks to the UFDs, but that's not what I want to do).

Thank you in advance your knowledge sharing

AlexanderZ · November 29, 2020, 20:59

describe your model (mesh) and why UDF doesn't work for your case.

you may change type of boundary condition manually or using TUI command

Achille · December 5, 2020, 08:58

Sorry if it was not 100% clear, I will try to give you a better understanding of my problem.

I am running a transient simulation and I would like to change the boundary condition at a specific time tc in a line l1 surrounding a 2D pipe (photo) :

if t<tc : set a temperature boundary condition to l1 : T=constant
if t>tc : set a heat flux boundary condition to l1 : Φ = 0

Is it possible to perform that using TUI commande or UDFs ?
If it's possible, please, can you show me the code I need to write ?

BehrouzMohammadian · December 29, 2022, 10:20

Hello, I have the same problem. Did you find any solution for it?

Thank you,

November 27, 2020, 04:30	Change Boundary Condition type during Transient simulation	#1
Achille New Member Achille Join Date: Nov 2020 Posts: 2 Rep Power: 0	Hello, I am asking for your help for a boundary condition problem in a 2D model. I have a pipe on which I would like to apply a temperature to one of the surfaces. However, after a while, I want to remove this boundary condition and let the heat flow freely through my pipe. It's a bit like heating an iron bar in a fire (I impose my temperature), then removing it from the heat (I remove my limit condition) to see how the surface temperatures evolve. (I know that it is possible to impose a temperature and make it vary over time thanks to the UFDs, but that's not what I want to do). Thank you in advance your knowledge sharing

November 29, 2020, 20:59		#2
AlexanderZ Senior Member Alexander Join Date: Apr 2013 Posts: 2,363 Rep Power: 34	describe your model (mesh) and why UDF doesn't work for your case. you may change type of boundary condition manually or using TUI command __________________ best regards ****************************** press LIKE if this message was helpful

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December 5, 2020, 08:58		#3
Achille New Member Achille Join Date: Nov 2020 Posts: 2 Rep Power: 0	Sorry if it was not 100% clear, I will try to give you a better understanding of my problem. I am running a transient simulation and I would like to change the boundary condition at a specific time tc in a line l1 surrounding a 2D pipe (photo) : if t<tc : set a temperature boundary condition to l1 : T=constant if t>tc : set a heat flux boundary condition to l1 : Φ = 0 Is it possible to perform that using TUI commande or UDFs ? If it's possible, please, can you show me the code I need to write ?

December 29, 2022, 10:20		#4
BehrouzMohammadian New Member Behrouz Join Date: Apr 2022 Posts: 7 Rep Power: 4	Hello, I have the same problem. Did you find any solution for it? Thank you,