[PSander]

My model is a long, horizontal cylinder filled with water and I want to calculate the heat exchange between cylinder and fluid, usinf OF8 and chtMultiRegionFoam.
To compare my results with given literature, I need to know the gradient, dTwater/dt, or in other words the change of bulk water temperature in °K per second.
My problem right now is how to calculate the bulk temperature. As I understand it, it is the average temperature for a volume.
I followed this explanation for paraView Average temperature in a portion of my domain, applying the filter "Integrate variables" on my of cells. In the spreadsheet, I switched attribute from Point Data to Cell Data. Then I divided the value under the T column by the Volume.

Does anyone know if this is the correct approach for my problem, or if there is another one?