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jkmalagi
Posts: 27
Registered: ‎11-15-2010
Accepted Solution

Flow rate convergence

127 Views, 2 Replies
05-22-2013 07:54 AM

Dear all,

I have run a steady state fluid flow analysis - the system has an air volume with one prescribed inlet/outlet & one external intake fan. The fan delivers .0014 m^3/sec flow into the system.

 

However, once the analysis is done & I add up the flow rate of all the nodes on the fan surface, I see that the flow is .00014 in^3/sec. I have tried different solvers, slightly denser mesh size & changing convergence parameters without success. All of these changes still show a similar result (.00014in^3/sec instead of .0014in^3).

 

What might be causing this behavior? I  have set "continue to next step" if the solution encounters oscillation so convergence may be a suspect. The archive file is too big to attach so I am sending analysis summary file.

 

I appreciate any feedback you can give me.

Jay

 

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Valued Mentor
AstroJohnPE
Posts: 498
Registered: ‎08-30-2012

Re: Flow rate convergence

05-23-2013 11:06 AM in reply to: jkmalagi

If you are really summing the flow rate at the nodes, that would be one problem. You need to select the faces of the elements, not the nodes. Hopefully that will get you closer to the target flow rate.

John Holtz, PE
Mechanical Engineer
Pittsburgh, PA

16 years experience with Simulation Mechanical
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Active Contributor
jkmalagi
Posts: 27
Registered: ‎11-15-2010

Re: Flow rate convergence

05-23-2013 10:51 PM in reply to: jkmalagi

Hello John

Thank you! That worked, I switched off smoothing options & selected faces instead of nodes & summed the flow rate values. The result are correct.

 

Best regards

Jay

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