Computational Simulation of High-Speed Steady Homogeneous Two-Phase Flow in Complex Piping Systems

A study was undertaken to predict steady flow conditions in two-phase steam/water flows in safety/relief discharge piping systems. The homogeneous-equilibrium model was used for the two-phase flow along with the ASME Steam Tables in subroutine form as a state equation. The approach can also accommodate single-phase flows of superheated steam or subcooled liquid. Subroutines were developed to simulate flows through isentropic area changes, abrupt area changes, adiabatic constant area pipes with friction, valves, two-phase shock waves, and mass addition at pipe junctions. These subroutines were combined to predict conditions in arbitrary complex piping systems. Sample calculations which treat both single line and multiple-branch piping systems are included.