Learning Forum

[hone zifu]

Currently, water falls from the entrance to the rotating surface and the flow of water is observed. The model is divided into two areas, the upper layer is 1.96mm thick and the lower layer is 0.04mm thick fluid area.

The first picture shows the ratio of water to air in the bottom layer. Currently, there is only air.

The second picture shows the interface between two fluid regions.

Does it have anything to do with the mesh being too fine?

[Prashanth]

Hello, the mechanism you are trying to model is not clear. Can you elaborate, a schematic maybe?

[hone zifu]

The overall model is as shown below. Because it is not a simple plane, I cannot use sweeping in the mesh analysis, so I divided the model into two parts, the upper thickness is 3mm and the lower thickness is 0.04mm. Use sharing to merge the two models together.

The mesh analysis uses a sweeping method to increase the thickness of the upper and lower blocks, but in the subsequent fluent flow, the liquid flows downward from the upper inlet and stops at the junction of the two models.

[hone zifu]

I am studying CMP liquid flow analysis. The gap between the wafer and the pad is about 0.1mm-0.04mm. However, after meshing, the fluent follow-up often fails.

[Prashanth]

Looking at the mesh, the cell size jump is massive between the two zones and the aspect ratio looks to be very high. You can work on getting a well resolved mesh with similar sizes.

[hone zifu]

So my liquid cannot flow down from the green part to the gray part because of the grid, because the fluent grid is at 0.4

[hone zifu]

Will such a mesh prevent the liquid from flowing?

 

[Prashanth]

Yes, massive cell jumps won't be helping with tracking the VOF interface. Will recommend adding biasing and keeping the mesh resolution consistent.

[hone zifu]

In addition, the flow of air and water in my VOF (Volume of Fluid) simulation is also quite peculiar.