EXPERIMENTAL AND NUMERICAL STUDY ON PRESSURE PULSATIONS UNDER VARIOUS ACOUSTIC BOUNDARY CONDITIONS IN PIPING SYSTEMS.

To improve design and troubleshooting techniques of piping systems for operating power plants, it is necessary to investigate, by experiment and simulation, the behavior of fluid inside the piping system in detail. This study was conducted using full-scale piping system under conditions that could seriously threaten the plant operation, by matching pressure pulsations, acoustic resonance, and piping natural frequency. Although piping vibration is reported to influence fluid pressure pulsations, there were no such examples of influence in this experiment. Knowing that the opening ratio of the pressure control valve affects the boundary condition for acoustic resonance, experiment and simulation at different opening ratios were conducted. It has been suggested that the cases in which a valve partially open at 25% or less should not be taken as a closed end. This finding conflicts with such a widespread design assumption.