Abstract
Flow-induced acoustic resonances in piping with closed side branches or T-junctions are one of the phenomena causing severe structural vibration and fatigue damage of piping and components in many engineering applications such as power plants. In the United States, the steam dryer of the boiling water reactor was damaged by high-cycle fatigue due to acoustic-induced vibration under a power uprating condition. Practical piping systems of power plants often have a steam flow, and moreover, the steam state can be not only dry steam but also wet steam, including nearly saturated conditions. Although many researchers have investigated acoustic resonances at side branches and T-junctions, it is considered that acoustic resonances under a wet steam flow have not yet been clarified since previous studies were mainly conducted under an air flow, and there have been few previous experiments performed under a steam flow, particularly a wet steam flow. The objective in this study is to investigate acoustic resonances in closed side branches with tandem- and coaxial-type arrangements under a wet steam flow. Experiments under a low-pressure condition for dry and wet steam flows were conducted and the results were compared. As a result, it is clarified that the effect of branch arrangements (single, tandem, coaxial) on the resonance amplitude under steam flow. In addition, differences in the amplitude response between dry and wet steam were evaluated.
