[hamid1]

Hi

I am modeling a suction inside a pipe, suction happens via a narrower pipe which is located inside a wider pipe,

Could anybody let me know if suction could be modeled through Fluent and if so, then which kind of B.C. should be used, is pressure outlet is ok, and should I put a negative amount for that (the pressure outlet)?

what is the maximum amount for Reynolds that I can use laminar flow inside the pipe, and if I am more than that threshold but less than 2300 (critical amount for turbulant regime inside a pipe), which model should I use, laminar or Turbulant?

thanks alot i advance

[hamid1]

please, could anybody reply me, it is very important for me, thanks all

[ComputerGuy]

Suction is simply a lower local pressure condition (there's nothing special about outward flow or inward flow).

As such, using a pressure outlet boundary condition is fine. The "inlet" condition can be pressure as well; setting it to 0 Pa and the outlet to -100 Pa (for example) will cause an outflow (suction).

If you have a Re < 2100, you can be reasonably certain that the flow is laminar.


ComputerGuy

[hamid1]

Thanks ComputerGuy, it helped me to be more sure about my work, thanks again...