I am attempting to mesh a complicated design (~80,000 faces) for a microchannel heat sink, as pictured, and I would appreciate some advice. I have tried a range of different mesh controls (especially face sizing and body sizing), mesh settings and element sizes, and all have failed to produce a working mesh. The most common errors are shown in the attached picture, in particular the one regarding "The following surfaces cannot be meshed with acceptable quality. Try using a different element size or virtual topology." However, I have already reduced the element size to 2x10^-6 m, which takes two days to resolve before failure.
Unfortunately I cannot alter the geometry significantly, as it is imported from generation in SolidWORKS as either a STEP or an x.t file. As such, any advice for how I can successfully mesh the geometry for CFD analysis in FLUENT would be greatly appreciated.
I can provide more details or the geometry file itself if required.
Thanks in advance.
Samuel D. Marshall Could you please shared a better image, maybe without the mesh.
Rajesh Alayil
Please find attached some images that might better visualise the geometry. The design is a 15mm long microchannel with two large "hills" or "rolls" that make up the major features. The shape was defined via topology optimisation in COMSOL, then a solid body was generated in SolidWORKS. I am hoping to use FLUENT to simulate a fluid passing over this geometry.
Samuel D. Marshall These micro features are important as it is the optimized design, but capaturing the same with mesh would be very challenging and even if you succeed, do you have the computational resource for analysis. I would recommend curtain level of simplification in design, thereby reducing the complexity and resource required. Also, manufacturer constraints needs to be considered as well.
Do you thing the design could be simplified?
Rajesh Alayil
Simplifying the model would be a good idea, but that presents its own difficulties. I have attempted to use the Repair tools (especially Repair Faces) in Design Modeller and SpaceClaim within the Ansys Workbench framework, as well as the Merge functions, and they have either not solved the meshing issue or failed outright. In addition, I cannot alter the COMSOL generation of results.
Do you have any advice on how to simplify the model without significantly altering the design?
If you can get 2019R1 OR R2 then there's a direct poly mesh approach using the new workflow. First of all generate a free mesh without much constraints.............there refine according to your computational need. this feature is really good .....give it a try.
https://www.youtube.com/watch?v=zFsa1Ezot8Y there is an example as well
Dear Samuel,
You can try to use ANSYS module ICEM CFD, where you can manually create an optimal mesh. ICEM CFD offers many possibilities but maybe the most important is the possibility to divide the fluid domain into a block structure where each block can be separately meshed according to your needs.
Cheers,
Marko
Thank you for your suggestions. In the end I solved the issue by importing the original mesh generated by COMSOL into SpaceClaim, then employing both the "Smooth" and "Reduce Faces" tools in tandem to simplify the geometry, before finally using SolidWORKS to turn the smoothed mesh into a solid body. This body retained many of the same features as the original, but was much less complex, having two orders of magnitude fewer faces. In turn, this permitted both meshing and heat transfer analysis in FLUENT.
Thanks again for your assistance,
Sam
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