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Minimum Size Constraints on Simulations Query

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Old   November 28, 2016, 14:29
Question Minimum Size Constraints on Simulations Query
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Craig Leddicoat
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Ahoy hoy,

Been running into bother meshing and running Fluent simulations involving exceptionally small geometry dimensions, around 1mm to 5mm wide fluid passages, and was wondering if there is some lower limit on the size Ansys can reasonably simulate?

From my analysis of the problem messages after trying a wealth of meshing methods, the automation seems to struggle with surfaces of the pipe walls and fluid boundaries and is creating interfacing at these dimensions that shouldn't be there. I have tried a few work around's already, including manually setting all the contact regions but I am still plagued by failing meshes, conflicting zone names and unresolvable contact regions.

https://i.imgsafe.org/c7512309b4.png
The image shows a sample of the heat exchanger concept, outer Fluid region, Central Pipe Wall Region and Inner Fluid Region.

Can anyone please advise a method to successfully mesh and discretize this model?
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Old   November 28, 2016, 16:08
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Lucky Tran
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There is a lower limit because Fluent works natively in meters, but it's around 1e-06 m. Fluent shouldn't have issues with mm scale features.
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Old   December 1, 2016, 06:02
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Craig Leddicoat
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You are correct, Ansys is capable of computing simulations at dimensions this small.

The errors seemed to stem from automated face pairing for connections on a series of layer 3D curved faces. I managed to resolve the conflict by better defining the contacting parts by grouping parts together in the Geometry editor to minimise the number of contact regions in the Mesh editor.
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