Multizone Blocking Decomposition failed.

  • Last Post 30 March 2020
  • Topic Is Solved
jaseemharry posted this 26 January 2019

I am a beginner to Ansys Fluent. I am trying to mesh a microchannel heat exchanger as part of my project. But i couldn't do the meshing part. It shows an error "MultiZone blocking decomposition failed".

I have modeled the geometry using Ansys Spaceclaim. I have attached the Archive file along. Please help me.

Attached Files

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peteroznewman posted this 27 January 2019

Replace the Multizone method with Hex Dominant method.  On the Mesh Details window, type 2.5e-2 mm for the Element Size and you will get a hex mesh.  That works in this case, but in general, never use Hex Dominant for CFD meshes because it can create horrible element shapes in the center, where you can't see them. This is not a problem for Structural solvers but is poison for CFD solvers.

Three elements across a fluid channel is way too few to properly compute the flow. You will want at least 10 elements across the channel and smaller elements near the wall.

Regards, Peter

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kkanade posted this 28 January 2019

following link may help you. 

if this helps you, please mark this post as 'is solution' to help others on forum.




jaseemharry posted this 11 February 2019

Thank you for the reply. and sorry i took so long. I was busy with my project.

ZIco posted this 28 March 2020


I am facing mesh problem and the generated mesh is not so smooth. i am using Multizone method with edge sizing and face mesh.

Please check the attachment for reference and help me to generate smooth mesh.



kkanade posted this 30 March 2020

you may need to use some edge sizing. 

as this was about failed multizone and is marked as 'is solution' , can you please create a new post in meshing to improve mesh. 




If this helps, please mark this post as 'Is Solution' to help others.

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ZIco posted this 30 March 2020

Thank you.