UDF describing the relationship between pressure loss and mass flow rate

- July 5, 2024 at 12:47 pm
  
  chen jia
  Subscriber
  
  Dear experts!
  I have a region of high pressure loss in my piping system.I want to insert a region similar to porous media in the piping system grid.The pressure loss in this region is equal to the square of the mass flow rate.How do I write UDF in this region.The inlet of the piping is the mass flow inlet and the outlet is the pressure outlet.Thank you in advance!
- July 5, 2024 at 1:01 pm
  
  Rob
  Forum Moderator
  
  Why can't you use porous media?
  - July 6, 2024 at 12:12 am
    
    chen jia
    Subscriber
    
    Dear Rob!
    Thank you for you reply!I have a long pipe containing compressed air, the air is modeled as an ideal gas model, if the pressure loss is large, the density change will be large and the corresponding velocity change will be large. I know the relationship between mass and pressure loss, but not the relationship between velocity and pressure loss.
- July 9, 2024 at 12:55 pm
  
  Rob
  Forum Moderator
  
  Not easy as the data access macros are mostly velocity based as Fluent solves for momentum. The fluxes will be available, but you'd then potentially be messing with momentum sinks as you wouldn't set a pressure loss.
  You may need to review what data you have and then rethink the modelling approach.