Learning Forum

[moranlouie]

Hi, all!

I need help understanding why my results are like this. On the left is temperature contours of freon flowing inside a copper tube, which also has temperature contours on the right. The copper tube is being heated by hot fluid. The inner tubing should be interfacing with the Freon walls, but...

[Rob]

That looks like the freon domain isn't connected to the tube. Check for connectivity and the presence of interface zones if you're using Fluent. n

[moranlouie]

Hello again and thanks for your help! There is a mapped-coupled interface between the two walls.n

[Rob]

That should work. Can you post a temperature plot on a plane that's on the axis. Node values off and zoom into one (or a few) of the tubes. If you do a heat flux report over the wall between the metal & freon how much heat is transferred? n

[moranlouie]

Sorry this took a while,nHere is a temperature plot of the fluid domain that is supposed to be heating the tubes and cavity, where the sources is coming from the bottom:nI got a heat-flux report using the calculator of the post processor. These are the total and average values:nArea Average of Heat Flux on freonwalls:  -576.223 [W m^-2], Area Average of Heat Flux on innertubes:  -3.97661e+07 [W m^-2]nSum of Heat Flux on freonwalls:  -2.27914e+08 [W m^-2], Sum of Heat Flux on innertubes:  -1.62972e+13 [W m^-2]nI'm not sure why it's negative. I couldn't get a heat flux report from the solver because fluent deleted all my results for some reason, but at leastthe post processor preserved them. Lastly, here are images of the mesh:nCould that gap be an issue? The entire mesh has 14,019,939 nodes.n

[Rob]

Is that a gap between the pipe and the core? You need the nodes to be common to both volumes or for them to be close enough that a non-conformal boundary will work (ie the surfaces are near enough the same but not connected in the geometry stage). If there's a physical gap nothing can pass over it: it means the two parts of the model are separate and no data can pass between the volumes. nSame goes for the outside: it must full surround and connect to the pipe. n