Import thermal field in FLUENT for initials conditions of a CHT probleme

Kodebar · March 8, 2018, 05:08

Hi Members,

I'am new to this forum and not a expert in CFD analysis. I would like to ask you if Ansys/FlUENT could import a temperature field to use it as a initial conditions for node of the model, if yes how could i do that ?
For a better explanation, i realize a first run of a steady-state thermal analyse of a solid/fluid model (like a simple cooling system) .So i could extract the thermal field easily. Now i want to create a transient CFD analysis to evaluate the time of cooling /and the evolution of the temperature and flux inside my whole modele (fluid + structure). I want the initials conditions of temperature of the CFD model correspond to the field of temperature of my steady-state run.
Is it possible to import the temperature field into fluent for intialize the CFD run ? If yes, could someone explain me the methodology ?

Kind Regards, and lot of fun !

LuckyTran · March 8, 2018, 11:58

For this to really work well, your mesh would need to be identical for both cases.

file=>interpolate and write the fields from the steady case and then file=>interpolate and read them into the transient case.

Fluent only does 0th order interpolation (maybe this has been improved in latest versions) so if your mesh changes, then you have some more work to do. You have to do the mesh-to-mesh interpolation yourself. As far as I'm aware, there aren't any built-in tools in Fluent to do this mapping. You have to do it yourself.

I don't really recommend this mapping approach if interpolation is needed because it's super important for the IC to be consistent with the grid and discretization. Even an analytically uniform temperature field for example can be inconsistent.

Kodebar · March 19, 2018, 07:59

Hi Luckytran,

Thank You for your replies. I appreciate very much the time spent on your answer.
I try to interpolate" the results of my first run (thermal-analysis with ansys stedy-state module) and then import my mesh in fluent but when i go to file=>interpolate (its the same mesh as before) the window pop-up but i can't read file, because the windows is grayed.

Could you please explain me step by step thow to completed the import of thermal field ? maybe i do wrong in exportation ? which kind of file i have to export ?

Thanck you a lot !

Have a good day .

Cheers !

March 8, 2018, 05:08	Import thermal field in FLUENT for initials conditions of a CHT probleme	#1
Kodebar New Member Jhon Join Date: Mar 2018 Posts: 2 Rep Power: 0	Hi Members, I'am new to this forum and not a expert in CFD analysis. I would like to ask you if Ansys/FlUENT could import a temperature field to use it as a initial conditions for node of the model, if yes how could i do that ? For a better explanation, i realize a first run of a steady-state thermal analyse of a solid/fluid model (like a simple cooling system) .So i could extract the thermal field easily. Now i want to create a transient CFD analysis to evaluate the time of cooling /and the evolution of the temperature and flux inside my whole modele (fluid + structure). I want the initials conditions of temperature of the CFD model correspond to the field of temperature of my steady-state run. Is it possible to import the temperature field into fluent for intialize the CFD run ? If yes, could someone explain me the methodology ? Kind Regards, and lot of fun !

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March 8, 2018, 11:58		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,751 Rep Power: 66	For this to really work well, your mesh would need to be identical for both cases. file=>interpolate and write the fields from the steady case and then file=>interpolate and read them into the transient case. Fluent only does 0th order interpolation (maybe this has been improved in latest versions) so if your mesh changes, then you have some more work to do. You have to do the mesh-to-mesh interpolation yourself. As far as I'm aware, there aren't any built-in tools in Fluent to do this mapping. You have to do it yourself. I don't really recommend this mapping approach if interpolation is needed because it's super important for the IC to be consistent with the grid and discretization. Even an analytically uniform temperature field for example can be inconsistent.

March 19, 2018, 07:59		#3
Kodebar New Member Jhon Join Date: Mar 2018 Posts: 2 Rep Power: 0	Hi Luckytran, Thank You for your replies. I appreciate very much the time spent on your answer. I try to interpolate" the results of my first run (thermal-analysis with ansys stedy-state module) and then import my mesh in fluent but when i go to file=>interpolate (its the same mesh as before) the window pop-up but i can't read file, because the windows is grayed. Could you please explain me step by step thow to completed the import of thermal field ? maybe i do wrong in exportation ? which kind of file i have to export ? Thanck you a lot ! Have a good day . Cheers !