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Simulation CFD

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*Expert Elite*
Dan.M
Posts: 618
Registered: ‎01-19-2009

volume flow rate inlet outlet

431 Views, 5 Replies
06-07-2013 05:45 AM

Hello,

Form what I understand the volume flow rate should be tha same at inlet and outlet.

In my model there is 1% percent difference between the two. 

What could be the problem?

Thanks

Dan

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Product Support
apolo.vanderberg
Posts: 307
Registered: ‎08-31-2011

Re: volume flow rate inlet outlet

06-07-2013 05:55 AM in reply to: Dan.M

Dan,

 A 1% error is typically more than acceptable for Engineering applications. As systems get more complex we will typically strive to ensure we are within 5% or less.

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*Expert Elite*
Dan.M
Posts: 618
Registered: ‎01-19-2009

Re: volume flow rate inlet outlet

06-07-2013 06:26 AM in reply to: Dan.M

Hello Apolo,

Thank you for the answer. 

Can I improve this relative error? Maybe change the Advection? or improve the mesh? 

Thanks

Dan

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Product Support
apolo.vanderberg
Posts: 307
Registered: ‎08-31-2011

Re: volume flow rate inlet outlet

06-07-2013 06:28 AM in reply to: Dan.M

Dan,

  What error % were you expecting?

 

Advection Schemes and mesh refinement are typically things to consider when trying to improve this however due to the fact that this is numerical approximation I would not expect to get 100% accuracy.

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*Expert Elite*
Dan.M
Posts: 618
Registered: ‎01-19-2009

Re: volume flow rate inlet outlet

06-07-2013 06:50 AM in reply to: apolo.vanderberg
Probably I would expect something very close to 0.
There are mathematical equations behind this which cannot be bend.
Thanks
Dan
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*Expert Elite*
OmkarJ
Posts: 440
Registered: ‎10-02-2012

Re: volume flow rate inlet outlet

06-07-2013 03:28 PM in reply to: Dan.M

Dan, 

 

Are you sure you have converged the solution? How about running 500 iterations more? 

Have you monitored the points and assessed their plots? ie, are they flat? 

What is your mass imbalance?

 

OJ

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