Boundary conditions do not play a role

MFiX
#1

Hello everyone.
I am confused about the results of the simulation, I have set the top and bottom (xz plane) as well as the front and back (xy plane) of the boxed portion of the diagram to be no-slip boundaries.The mesh size of the model is 75 μm, and the number of meshes in x,y,z direction is 267,40,10.

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However, I found that the flow velocity at the wall is not 0 after the actual run, and the flow velocity at the front and the back are not symmetrical, the boundary condition doesn’t seem to be working, why is that? The results of my simulation are as follows, I hope you can help me to solve the problem.
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nosilp_plfluid0.75.zip (61.7 MB)

#2

How many cells do you have across that small feature?

#3

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The narrower channels on either side are 75 microns wide and the wider channels in the middle are 150 microns.Is it because my grid is too big? The grid size is 75μm75μm75μm

#4

So, if you only have one cell across the 75um section, then you will never resolve the flow profile in that channel.