Testing the tee branch components

• Basic test:
  • model for join case (similar for split case)
  • comparison of tee branch models
  • used for fine tuning of parameters in TeeBranch
  • split case
    • dynamic pressure increase
    • use substitutional pipes with negative length
• Adding one pipe to the pressure source:
  • large pressure oscillations due to bad initial values
  • choosing better start pressure → amplitude decreases
• Adding one pipe to the mass flow source:
  • simulation stops with an error
  • Newton solver can't find initial values
  • giving reasonable initial values manually doesn't help
  • only TeeBranch works (with positive pipe length)
• Homotopy initialisation:
  • start with a simplified model to find initial values
  • change model continuously to target model
  • possible with Modelicas homotopy function
  • works for many thermo-fluid models
  • doesn't work here (so far?)