I have a machine that includes a workpiece which can be considered as 1200 degree Celcius and it is rotating around its center. I have around 2.5 million mesh and the minimum orthogonal quality is 0.152. Can anyone help me? The continuity residual diverges after 2000 iterations. The machine is made up of steel my enclosure is air. I have used discrete ordinates for radiation and moving wall boundary condition for the workpiece and the angular speed is 1000 rpm. I assign 1200 degree Celcius for boundary and heat flux BC is automatically selected for its shadow. I always get the message that the turbulent viscosity ratio is limited by 1e+05 for xxx number of cells. The number fluctuates throughout the iterations. I am using the k-epsilon model for turbulence. All cell zones are selected as participants in radiation. Since radiation is activated, I am using PRESTO! for the pressure solution method. The others are set as default.
Thank you in advance
Hi Furkan,
What are the mesh qualities, i mean skewness and aspect ratio ?
Turbulent viscosity ratio warning is most likely due to the mesh quality, try improving your mesh.
Regards,
Rajesh.
Hi Rajesh,
When I check the mesh, it is said that "used modified centroid in 2 cells to prevent left-handed faces. The minimum orthogonal quality is 0.153367 and the maximum aspect ratio is 553. I have used fluent meshing to mesh all the parts with polyhedra. There are around 2.5 million elements. I have used share topology in SpaceClaim to assign steel-steel and steel-air interfaces. After it is being done, I assign 2 boundary layers for fluid and 1 boundary layer for solid when there is an interface. The machine is in a room so I used pressure outlet boundary condition for all surfaces of the enclosure. I used the DO model with 6*6 pixels of theta and phi. I assigned all solid cell zones as a participant in radiation. The machine is drawn with a workpiece which is 1200 degrees. It is turning around its center and I am using a steady-state solver. I don't know how to learn skewness value in fluent because although I perform a mesh check, it doesn't appear in TUI.
In this case, the maximum temperature should be around 1200 degrees but in TUI, it is said the temperature is limited to 3273 degrees in 3 cells on zone 16114 which is the enclosure basicallly. I have added my residuals after 4500 iterations using the k-epsilon model.
Thank you in advance.
Regards.
Furkan Enes.
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