[arashjkh]

Hi everyone,

I'm modelling a high-pressure pipeline, say 7 [MPa], in ANSYS Fluent 2020 R2. I've meshed it via ANSYS Meshing, and converted my mesh to poly using ANSYS Fluent's built-in poly-mesh conversion method. My model is a T-junction as follows:

1.jpg

The aspect ratio of mesh is 300 and Orthogonal quality 0.23.

The mass flow rate is about 70 [kg/s], density of the fluid is about 50 [kg/m3], and its velocity equals 10 [m/s] in the main pipe.

I'm using k-epsilon model for the turbulence, however I'm getting "Turbulent viscosity limited to viscosity ratio of 1.000000e+05 in xxx cells", and it never vanishes! Interestingly, all my residuals converge up to even e-10! I don't know what contributes to this problem and have tried many ways to resolve this problem. The BCs, ICs, and the mesh are fine. Even I've read all the relevant threads in CFD-online website! Attached you can find some contours of my simulation:

3.png
4.png
5.png
6.png

Thanks for your time!

[AlexanderZ]

density of aluminum is 2.7kg/m3 your fluid is 50kg/m3
don't you think its weird?

[arashjkh]

Originally Posted by AlexanderZ

density of aluminum is 2.7kg/m3 your fluid is 50kg/m3
don't you think its weird?

Hi,
It's a gas pipe, with a pressure of almost 7 [MPa]. At this pressure methane is super-dense, as its density equals 50 [kg/m3] (approximate). Besides, the pipe wall is steel.
You can take a look at the table in this source:
https://www.engineeringtoolbox.com/m...re-d_2020.html