Problem: Cannot get Results to work in post processing

  • Last Post 06 August 2019
mattsarg55 posted this 05 August 2019

I am currently working on modeling flow through a butterfly valve when it is open/closed and at a few other angles. I have gotten the closed version to work and now I am trying to get the open version to work using the same model (Laminar flow, 1-inlet/1-outlet, same flow velocity, same solving methods). However, after multiple attempts I keep getting results that are inf (look at picture below titled 'contour prob'). My continuity is going off the charts so I assumed to change my mesh and make it a higher density, but to no avail. I have tried multiple meshing attempts all different so I am not sure if this is the problem anymore.

Could anyone provide insight onto what may be causing this? Like I said the closed version worked and now all I did was turn the valve to be open in SpaceClaim.

Below I will post a pic of the mesh as well, keep in mind this is just one of MANY meshes I have tried.

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mattsarg55 posted this 05 August 2019

rwoolhou posted this 05 August 2019

Can you put a plane on the y-centre plane? Want to check you've got mesh in the right places.  What are the boundary condition? Also, what's the mesh quality?

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  • mattsarg55
mattsarg55 posted this 05 August 2019

As far as boundary conditions go the only thing I have altered from the norm is the velocity at the inlet to be 24.384 m/s. Walls and interior are not altered, and the outlet pressure is at 0 pa so that we are operating at atmospheric pressure.

Thank you so much for the response this has been driving me nuts lol

mattsarg55 posted this 05 August 2019

That particulary mesh has a minimum orthogonal quality of 0.00.

a maximum skewness of 1.728177

124 skewed cells

and a cell count of 242852

rwoolhou posted this 06 August 2019

That'll definitely not help convergence. Please review where the poor elements are and retry with a mesh that's not got flat elements in it. 

mattsarg55 posted this 06 August 2019

How would I go about doing this though? Where are my poor elements? How would I make it so these flat elements do not appear?

rwoolhou posted this 06 August 2019

In Fluent Meshing insert a mesh improvement operation after "Create Volume Mesh" has completed. There are also some options in the Display menu to view the mesh. 

Assuming the valve touches the outer casing have a look in the geometry for where the valve & casing meet.