Abstract
Steam piping and components in many industrial applications such as power plants sometimes experience structural vibration and fatigue damage caused by flow-induced acoustic resonance in piping with closed side branches. The steam state in the practical steam piping can be not only dry steam but also wet steam. From our previous research, higher acoustical damping was confirmed under low-pressure wet steam than that under low-pressure dry steam, which is considered to be caused by the existing liquid phase in a wet steam. Moreover, the effect of the liquid phase in wet steam on the pressure fluctuation was considered to be small at a high pressure since the maximum amplitude under a high-quality wet steam increased with increasing density ratio. In this study, we tried to investigate the combined effects of the steam wetness and static pressure on the pressure fluctuation. We conducted experiments on acoustic resonance in a single side branch under wet steam flow with the steam wetness and static pressure as parameters to extract and evaluate the dominant factors affecting the mechanism of acoustical damping under a wet steam flow.
