how to impose pressure loss gradient in Fluent ?

- November 16, 2020 at 4:38 pm
  
  manelaero2020
  Subscriber
  
  Hello every body nI am simulating a fluid in a cyclonic filter with particles injection. nI have as inlet BC : Velocity inlet or mass flow inlet ; there is a constraint : the pressure loss must'nt exceed 5 mbar ( P_outlet-P_inlet) ; i know my pressure inlet ( 110155 Pa) nHave you an idea please how can i impose this pressure loss constraint in BC (Ansys Fluent) ? In other way : What i must impose in inlet and outlet ? I can't impose Pressure inlet BC since i will use velocity inlet . I can only impose pressure outlet . nThanks you for helpnBest regards n
- November 16, 2020 at 5:00 pm
  
  Rob
  Forum Moderator
  
  You can either set a pressure loss or a fixed flow inlet. For a fixed dP the mass flow is calculated, from a known flow you find the dP. For a cyclone I'd fix the flow (velocity) and then see what the pressure loss is. n
- November 16, 2020 at 6:03 pm
  
  Amine Ben Hadj Ali
  Ansys Employee
  
  Total pressure loss is most important here. Start with fixed velocity then switch to pressure inlet pressure outlet.n
- November 16, 2020 at 7:26 pm
  
  manelaero2020
  Subscriber
  
  Array Can you please explain me furthermore what do you mean by Start with fixed velocity then switch to pressure inlet pressure outlet ?Do you mean i try at first : nVelocity inlet /pressure outlet ; then i try pressure inlet /pressure outlet ? nThank you
- November 17, 2020 at 9:43 am
  
  Rob
  Forum Moderator
  
  I'd run with velocity in & pressure out and report the inlet pressure to find the dP. nIf you really need to run with a known dP I'd get the flow field running with a velocity in and then switch to a pressure boundary once the flow field was established. This is purely down to the swirling flow: the pressure drop is a function of the normal mass flow losses but also of the swirl. Look up vortex amplifiers for more details on that. n