problem in generating hexa dominant mesh ?

  • 104 Views
  • Last Post 06 June 2019
sooraj546 posted this 04 June 2019

I am trying to mesh a furnace having external dimensions of 2.7 m radius and internal radius of 1.3 m, I have already developed a tetrahedral mesh without much problem but i want to c if hexa dominant mesh will give better results as this mesh is more physics dependent and more flow oriented.

As you can c over here there are cone shaped burners all over the exterior face of the furnace. Each burners has 9 inlet tubes which carry fuel into the furnace for combustion to happen etc. its dia is around 9.5 mm. When i use hexa dominant mesh externally everything seems ok but internally below shown problems occur as shown in fig a and b. All the details of sizing and face mapping used has been shown in figure d. 

b)

c) burner details

d)

e) edge sizing for inlet tubes has been given as shown below

f)

g) over all mesh looks good but internal problem exists 

h) edge sizing done here as well

 

any advice in making the mesh further good using  hexa-dominant mesh how to get rid of this internal issues ?

Order By: Standard | Newest | Votes
rwoolhou posted this 04 June 2019

That's about normal for the hexa-dominant method. It's designed to give a good surface mesh & few layers of good cells & efficiently fill the middle: only Mech can use it and even then it's rarely used now as the quality is usually awful. It's not supposed to be available for CFD models so I'll flag that internally. 

For the above scenario I'd suggest over refining (maybe with decomposition) the burner ports & jet regions using tets. Then use Poly conversion. If you can move to 2019Rx use the Fluent Meshing workflow and direct poly mesh. 

  • Liked by
  • sooraj546
sooraj546 posted this 04 June 2019

Yes sir i have already tired that .....................what i did is i used sphere of influence at each burner got a very refined mesh across it, then used tetrahedral mesh to generate pretty good mesh as shown below

the problem here is element size it too much then i went of set up section of the FLUENT made it polyhedral mesh (Make Polyhedra)

This what you meant sir?

rwoolhou posted this 04 June 2019

That's one option. If you can get 2019R1 then there's a direct poly mesh approach using the new workflow.    

  • Liked by
  • sooraj546
sooraj546 posted this 04 June 2019

oh thanks a lot sir

 

sooraj546 posted this 04 June 2019

i AM USING 19.2 but my interface is really different from whats shown over here, I get it its ANSYS2019R1 we dnt have it sir! what i have done earlier will do i guess ...?

rwoolhou posted this 04 June 2019

I think it's in R19.2, but you'll have to launch Fluent in meshing mode outside of Workbench. 

  • Liked by
  • sooraj546
sooraj546 posted this 04 June 2019

oh let me c sir, thanks a lot for that suggestion

sooraj546 posted this 06 June 2019

No sir that feature is not available in ANSYS19.2 we will have to install R1 or R2 for that..............! 

rwoolhou posted this 06 June 2019

Oh well, it's worth it! 

To add, the mesh generated in 2019Rx can be read into R19.2 if you want a local installation & still use a campus system. Not sure how the licence manager will work: that's one for Installation! 

Close