how to understand the flow pattern difference using pressure outlet and outflow?

- May 31, 2018 at 7:54 am
  
  cqbgood
  Subscriber
  
  Hi all,
  
  Recently, I would like to simulate a case in a fixed bed with a hollow tube inside(outlet tube). the B.C of this hollow tube is set as pressure outlet and outflow, but the flow pattern is totally different(see below pic.), how to explain this results? which one is better for my case, thanks.
- May 31, 2018 at 8:50 am
  
  cqbgood
  Subscriber
  
  Additional information: the red tube in the Pic. is the defined hollow tube, there is empty or no computational domain in the case for the tube. here just show the location.
- June 1, 2018 at 1:22 am
  
  raul.raghav
  Subscriber
  
  Could you attach your workbench archive file? If you're not sure how to create and share a workbench archive file, please refer: Saving & sharing of Working project files in .wbpz format
- June 3, 2018 at 10:37 am
  
  Raef.Kobeissi
  Subscriber
  
  Selecting Outflow makes you lose control over how much the outlet pressure would be but at the same time, it prevents the simulation to backflow. If you select outlet pressure then you are telling Fluent exactly what pressure you would like to have at the outlet. By selecting a determined outlet pressure and a velocity inlet, the software would then calculated the inlet pressure.
  
  As Rahul said, if you can send us the case we would have a look at it.
  
  Cheers