Problem with open loop systems

Hi, I am modelling an open loop system (hot injection) with Feflow 6.2 using multilayer well. My problem is that below the well and thermal affected hot zone I find a kind of inverse thermal affected cold zone. I have already verified Delaunay criterion and Peclet number. Could the problem be due to the difference between horizontal discretization (0,1-0,05 m ) and vertical discretization (1m)?Thanks for your suggestions!

The problem is known. Usually, the inverse thermal affected zone may be attributed to the spatial discretization. I suggest to refine the model vertically.

Thanks for your reply! I know that vertical refining is useful for that kind of problem. But as I have found this kind of problem especially in area with more horizontal refining, I was wondering if even the difference between horizontal refining (from 0,05 to 0,1) and vertical refining (1 m) could be an important factor. Thanks.

Yes, theoretically the aspect ratio could also play a role. However, aspect ratios with one or two orders of magnitude should be handled easily by FEFLOW. I suggest to systematically refine horizontally and vertically and explore the numerical output (e.g. temperatures). You could also try to take the Peclet number into account (Auxiliary Data in the Data panel)

Thanks a lot for your suggestions.

Elena

Hi,I'm trying to enter the geothermal gradient in a pattern consisting of four layers,
I tried to assign to Temperature BC-current expression the formula of the geothermal gradient but it don't run. Someone know how do it?

Thank you

If you intend to assign the temperature as a vertical thermal gradient then the plugin [i]SetGG[/i] may be useful.  Here is a short description:

[b]Set an initial 3D temperature distribution[/b]
As a prerequisite to work proberly two things have to be prepared before executing this IFM module:
[list]
[li]At the first slice an intial temperature has to be set.[/li]
[li]At the first slice a nodal reference distribution named "gg" has to be created and initialized with the value for the geothermal gradient which shall be used (typically 0.03 Kelvin per Meter). [/li]
[/list]
The IFM moduel is executed by clicking on it. Please contact the FEFLOW Support team in case you are interested in the plugin: https://www.mikepoweredbydhi.com/support