Two phase flow iconTwo-Phase Flow Solutions

Two phase flow encountered in industry systems and processes are complex and often lends itself to improvement and optimization. Flownex®’s two phase capabilities provides the user with the capability to simulate, design and analyse two phase systems which cannot be simulated using simple single phase compressible or noncompressible fluids and methods.

The process industry can make significant savings using Flownex to simulate, predict and optimize outputs in some of the following phenomena accounted in steam simulation:

  • Vibration root cause analysis.
  • Pipe knocking & water hammer prevention.
  • Steam line insulation and heat transfer to the atmosphere.
  • Pipeline venting, pressure regulating valves.
  • Steam/Water filtering.
  • Heat transfer.
  • Boiling.
  • Condensation.
  • Phase separation.
  • Flow regime approximation.
  • Critical mass flux (choked flow).


 Flownex®’s two phase capabilities can be divided into the following broad categories:

  • Pure two phase fluids: two phase fluid in its pure form.
  • Two phase with a noncondensable gas: low noncondensable gas mass fraction, typically systems with unwanted air ingress.
  • Psychrometry: low two phase mass fraction, typically HVAC systems.


As with the Flownex® single phase capabilities, the two phase capabilities are based on the fundamentals of mass, momentum and energy balance, enabling the fundamental simulation of two phase thermo-hydraulic systems. Flownex® employs a homogeneous mixture model approach in its flow elements (pipes, valves etc) assuming that the liquid and gas phases are evenly distributed over the cross-sectional area of the flow path and that the pressure, temperature and velocity of the phases are the same. Additional to the homogeneous mixture model, Flownex® also allows for phase separation and level tracking in containers. This enables the separation of the liquid and gas phases (the gas phase accounts for the two phase vapor and noncondensable gas) within the container while the outflow phase from connections at various container heights are determined.