[snappyHexMesh] Modeling STLs with Internal Cavities and Thin Walls

BrownieBytes · March 26, 2024, 01:42

Hello everyone,

I've been working on this problem for far too long and at this point I'm throwing a Hail Mary. If anyone can get this thing to properly mesh, my research will be back on track for the first time in months. Linked is the STL and eMesh [https://github.com/Iakana/Cavities_T...in/reactor.zip].

I am trying to model the thermal-hydraulics inside this complex solid. Inside the solid is a power producing liquid. The solid itself is a high temperature metal or ceramic (TBD, but not important). The solid is then submerged in a liquid similar to the one inside the solid. The end goal of the research is to model the two flows at steady state using chtMultiRegionSimpleFoam.

The problem is that even after adapting snappyHexMesh tutorials and searching for answers, I can't get a successful mesh. If someone out there could make a snappyHexMeshDict that actually worked, I'd be so grateful.

Best,
BrownieBytes

BrownieBytes · March 31, 2024, 22:42

Hey all,

I have finally gotten the results to look at least partially correct. The problem now is that I need to correctly model the thin walls. As I have mentioned before, there are only three regions: fuel, steel, and coolant. All fuel is separated from coolant by steel, meaning that there should only be a fuel-steel boundary and a steel-coolant boundary. Unfortunately, snappy is also producing a fuel-coolant boundary, a problem produced (I think) because the steel is only a millimeter thick when the total mesh is 2x2x3 meters.

So, what can I do to make sure that snappy correctly defines the thin walls? If I run snappy with the inner and outer shells separately, snappy does an excellent job with no problems, so I think the problem is that these two walls are too close together, but I don't want to keep adding refinement levels or a finer blockMesh.

Any suggestions?

March 26, 2024, 01:42	Modeling STLs with Internal Cavities and Thin Walls	#1
BrownieBytes New Member Join Date: Nov 2023 Posts: 4 Rep Power: 3	Hello everyone, I've been working on this problem for far too long and at this point I'm throwing a Hail Mary. If anyone can get this thing to properly mesh, my research will be back on track for the first time in months. Linked is the STL and eMesh [https://github.com/Iakana/Cavities_T...in/reactor.zip]. I am trying to model the thermal-hydraulics inside this complex solid. Inside the solid is a power producing liquid. The solid itself is a high temperature metal or ceramic (TBD, but not important). The solid is then submerged in a liquid similar to the one inside the solid. The end goal of the research is to model the two flows at steady state using chtMultiRegionSimpleFoam. The problem is that even after adapting snappyHexMesh tutorials and searching for answers, I can't get a successful mesh. If someone out there could make a snappyHexMeshDict that actually worked, I'd be so grateful. Best, BrownieBytes Last edited by BrownieBytes; March 26, 2024 at 14:39.

March 31, 2024, 22:42	Some progress	#2
BrownieBytes New Member Join Date: Nov 2023 Posts: 4 Rep Power: 3	Hey all, I have finally gotten the results to look at least partially correct. The problem now is that I need to correctly model the thin walls. As I have mentioned before, there are only three regions: fuel, steel, and coolant. All fuel is separated from coolant by steel, meaning that there should only be a fuel-steel boundary and a steel-coolant boundary. Unfortunately, snappy is also producing a fuel-coolant boundary, a problem produced (I think) because the steel is only a millimeter thick when the total mesh is 2x2x3 meters. So, what can I do to make sure that snappy correctly defines the thin walls? If I run snappy with the inner and outer shells separately, snappy does an excellent job with no problems, so I think the problem is that these two walls are too close together, but I don't want to keep adding refinement levels or a finer blockMesh. Any suggestions?