Learning Forum

[ali akbar]

Hello everybody. I'm new to ansys fluent and I have problem in modeling and meshing a perforated plate in an air heater. I don't know what is wrong in my modeling or meshing that I couldn't reach a converged result in fluent. my first question is that true to use a surface for perforated plate because it caused to overlapped mesh and the secod question is that should I use form new part in ansys design modeler?.

[YasserSelima]

If you are not interested in FSI interaction, do not have any solid in your geometry. Just include the fluid domain in your geometry. .. perforated plate, only draw the holes where the fluid pass and extrude them. Don't include the solid. This wastes time and causes problems if you don't set everything right.n

[ali akbar]

Thank you for your reply but I don't think this is a FSI problem and in my problem it's just connection between perforated plate and fluid. And in my problem in the refrence problem it uses connection between them so I must keep solid body in my geometry.n n

[Rob]

How did you split out the plate? You should finish up with two fluid zones, a wall (plate) and some interior faces (the holes). No need to include the plate thickness unless you're going to use enough mesh to pick up the edge separation etc on the holes. n

[ali akbar]

Yes Rob. First of all I made a fluid zone and then made a plate and split my fluid to two fluids by that surface plate( before I made surface from one face of the plate ) , after that substract the plate and kept my plate . Then I put cylinders on the plate and split the cylindrical face by plate and finally I named the plate wall and all of the cylinders' face as interior but when I wanted to transfer my mesh from Ansys meshing to fluent I got this error The mesh file exporter could not resolve cyclic dependencies in overlapping contact regions. Please try to Repair Overlapping Contact Regions. but if I use plate thickness, I could export the mesh but my solution didn't converge.n

[Karthik R]

Hello,nCan you please share some screenshots? It seems like you might have additional cylindrical surfaces still in your geometry and hence the warning. Please make sure that you don't have these additional surfaces. Also, are you performing the shared topology operation on your CAD? If you are not, you should.nPlease share some screenshots that would help us understand your geometry as well as the operations you are performing better.nThank you.nKarthikn

[ali akbar]

Hello Sir. I explain all i did step by step from the screenshot that I share.n1.modelling air heatern2.modelling platen3.making surface from bottom face of plate and suppressing the platen4.slice the fluid body to two body by the surfacen5.creating cylinder as holesn6.using patternn7.using facesplit to split the cylindrical surface by surface platen8.name cylider faces as interior and plate as walln9.form partnI could export the mesh to fluent but the solution didn't converge and some warning like temperature is limited to 500 in ... elements appeared between solution.nn

[Rob]

The geometry looks OK, but if you're hitting the temperature limits the solver isn't happy. Can you post images of the mesh and flow field? n

[DrAmine]

Just a question: we released with 21R1 a perforated wall model to incorporate flow passages without having to resolve the solid wall. Have a look into thatn

[ali akbar]

The geometry looks OK, but if you're hitting the temperature limits the solver isn't happy. Can you post images of the mesh and flow field?https://forum.ansys.com/discussion/comment/104271#Comment_104271

Oh, I apologize for late reply.nn

[DrAmine]

Can you issue a mesh check and quality check in Fluent and post the output here?nCan you summarize the boundary conditions and the model options involved in your case?n

[ali akbar]

Can you issue a mesh check and quality check in Fluent and post the output here?Can you summarize the boundary conditions and the model options involved in your case?https://forum.ansys.com/discussion/comment/106748#Comment_106748

Yes sir.n Volume statistics:nminimum volume (m3): 2.910059e-12nmaximum volume (m3): 1.719630e-07ntotal volume (m3): 2.249845e-02nFace area statistics:nminimum face area (m2): 2.861980e-08nmaximum face area (m2): 6.931671e-05nChecking mesh.....................................nDone.nMesh Quality:nnMinimum Orthogonal Quality = 1.11949e-01 cell 1373 on zone 7 (ID: 109962 on partition: 2) at location ( 7.69299e-01 -4.10976e-03 -1.36944e-01)n(To improve Orthogonal quality , use 'Inverse Orthogonal Quality' in Fluent Meshing,nwhere Inverse Orthogonal Quality = 1 - Orthogonal Quality)nnMaximum Aspect Ratio = 3.77237e+01 cell 2105 on zone 7 (ID: 11538 on partition: 1) at location ( 4.01631e-01 -2.50000e-03 -1.36984e-01)nIn inlet I used velocity inlet and in outlet I used pressure outlet. for absorber I assumed it a heated wall and other as wall.nI used energy and k-omega standard model.n

[Rob]

I can't read the scale on the plot, is that really 6x10^62 m/s ?!?n