Learning Forum

[HamishE]

Hi,

I'm currently modelling a Polymer electrolyte membrane fuel cell and I'm facing some problems with the mesh in workbench meshing. I want a highly structured hexahedral mesh. The PEMFC consists of an MEA which is essentially 5 very thin rectangular prisims stacked on top of each other, and bi-polar plates and gas channels on the top and bottom. These channels imprint onto the surface of the MEA when I share the topology for the entire domain (which is recommended by the handbook). The middle 3 layers I can mesh using a sweep method, but the outer 2 layers cannot use the sweep method due to the gas channel imprint on the top surface (pic 1. Bi-polar plates and channels hidden).

My current solution is to split the outer layers of the MEA into 2 segments. The inner can be meshed using the sweep method and the outer I just tell to mesh with hex dominant method. This works for almost the entire domain except the corners (pic 2) which make these random pyramid and wedge elements. I have tested this in fluent and it works alright, but I would prefer to have a fully structured mesh.

Does anyone know how I can stop workbench from making these ugly elements in the corners of the MEA? Preferably in workbench, but if you think I need to change software to a different mesh package, let me know. THANKS!

[Rob]

Don't use hex dominant method. It's designed to give a good surface & first layer mesh for Mechanical and then fill the rest in with rubbish. Either decompose the two layers so you include the flow channels or see if multizone will work. If you use the former use a named selection to put the two volumes into the same zone in Fluent.

[HamishE]

Thanks Rob! The multi-zone method worked a treat and now the mesh is nice and uniform. I can now recombine that outer layer of the MEA into 1 layer so it's the usual 5 layers thick rather than 7.

[Amin Yousefi]

Hello

I am trying to mesh my PEMFC with Fluent. I imported the CAD file from spaceclaim and looks ok. When I start the surface mesh it gives me an error of "Error in CAD Import". error occured during the import. I am not sure what i causing this. Any idea would be appreciated.

Thanks,