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-   -   Geothermal gradient (https://www.cfd-online.com/Forums/star-ccm/229390-geothermal-gradient.html)

Y27 August 6, 2020 18:16

Geothermal gradient
 
Hi, I Hope you are well. Thank you for taking the time to read my post!

I am attempting to simulate a user defined thermal gradient but I have found no references to this in the documentation or online.

I have attempted this by defining the temperature at the top and bottom surfaces of the solid part - this worked - but only for steady state conditions!

Can anyone shed any light in regards to the documentation available on the subject of creating a thermal or temperature gradient in star-ccm?

If anyone has any suggestions towards the methodology I should be using I would also be extremely grateful for your input.

Thank You!

cwl August 8, 2020 01:47

Temperature gradient - where?
Temperature gradient - when?

ping August 8, 2020 03:56

you can use a table or a field function to set the initial varying temperature of the region cells and or boundaries.
if you want to continue to apply some forced temperature either fixed or varying during the solve then you need to use the volumetric heat source setting in the region.
one method of doing this is shown in this help topic: Simulating Physics > Region Sources > Prescribing Constant Temperature in Fluid Cells

Y27 August 8, 2020 12:17

My Apologies - I should have been more specific in my explanation. I am simulating a geothermal well, which transfers heat from the surrounding ground --> to a metal pipe buried vertically in the ground --> to the water which flows through the pipes passage.

I would like to set a temperature gradient where temperature increases with ground depth at a liner rate.

In my op, I stated that the crude process i used worked for steady state but not for unsteady. This was incorrect. After further investigation and many more iterations, it did work for unsteady too.

However, what i am actually trying to achieve is much more a kin to Ping's reply. I would like the temperature profile of the ground to be constant throughout the entirety of the simulation (apart from any near boundary interactions that may occur), rather than being computed during the simulation.

I hope this helps, if i have left anything out I will be glad to add it to the conversation.

Thanks!

Y27 August 8, 2020 12:27

Thank you very much for you response, I will be sure to look into this asap. I noticed what appears to be a problem in an earlier iteration of the project i am working on so I must first address this issue before anything else. I am going to start a new post for this and i will be sure to revisit this once the time comes to implement the temperature gradient in the model. Thank you for reply, much appreciated!


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