Experimental Investigation for Influence of Static Pressure and Steam Wetness on Pressure Fluctuation of Acoustic Resonance in Coaxial Side-Branch under Wet Steam Flow

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 the piping and components in many engineering applications such as power plants. 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. From our previous experiments under low-pressure dry and wet steam flows using a single side branch, higher acoustical damping was confirmed under wet steam than that under dry steam, which is considered to be caused by the existing liquid phase. Although the static pressure in practical steam piping is often higher than that in our previous experiments, the effects of the static pressure on acoustical damping under a wet steam flow have not been clarified. Thus, we constructed a new test facility that can be used to perform continuous flow test under dry and wet steam flows with higher pressures than our previous test facility. In this paper, we give an overview of the new steam test facility and some experimental results for the acoustic resonance in a single side branch under higher-pressure dry and wet steam flows than those in our previous studies, using the new facility to investigate and evaluate the effects of the static pressure.

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Experimental Investigation for Fluctuating Pressure of Acoustic Resonance in Tandem and Coaxial Side-Branches under Wet Steam Flow

The Proceedings of the Dynamics & Design Conference ◽

10.1299/jsmedmc.2016.619 ◽

2016 ◽

Vol 2016 (0) ◽

pp. 619

Author(s):

Yuta UCHIYAMA ◽

Ryo MORITA ◽

Fumio INADA

Keyword(s):

Experimental Investigation ◽

Acoustic Resonance ◽

Steam Flow ◽

Wet Steam ◽

Fluctuating Pressure ◽

Wet Steam Flow

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Flow-Induced Acoustic Resonance in a Closed Side Branch Under a Low-Pressure Wet Steam Flow

Journal of Pressure Vessel Technology ◽

10.1115/1.4035271 ◽

2017 ◽

Vol 139 (3) ◽

pp. 031306 ◽

Cited By ~ 1

Author(s):

Yuta Uchiyama ◽

Ryo Morita

Keyword(s):

Acoustic Resonance ◽

Low Pressure ◽

Side Branch ◽

Steam Flow ◽

Wet Steam ◽

Wet Steam Flow

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Experimental Investigation for Acoustic Resonance in Tandem Branches Under Each Dry and Wet Steam Flow

Volume 4: Fluid-Structure Interaction ◽

10.1115/pvp2015-45456 ◽

2015 ◽

Cited By ~ 1

Author(s):

Yuta Uchiyama ◽

Ryo Morita

Keyword(s):

Power Plants ◽

High Cycle Fatigue ◽

Acoustic Resonance ◽

The United States ◽

Steam Flow ◽

Piping System ◽

Wet Steam ◽

Resonance Amplitude ◽

Piping Systems ◽

Wet Steam Flow

Flow-induced acoustic resonances of piping system containing closed side-branches are sometimes encountered in power plants. In the United States, the steam dryer in boiling water reactor had been damaged by high cycle fatigue due to acoustic-induced vibration under a power uprating condition. The steam piping systems of current power plants often have nearly saturated wet steam condition. The side-branches of current power plants vary in their configuration (single, tandem, and coaxial), number, and so on. Therefore, many types of flow-induced acoustic resonance at branch piping have been investigated by many researchers. However, most of previous studies were under air flow condition and there were few previous experiments under wet steam flow. In this study, some types of the acoustic resonance at branch piping are investigated by conducting experiments under each dry and wet steam conditions. As a result, it is clarified that influence of branch configurations (single or tandem) on resonance amplitude and frequency under steam flow. In addition, their differences between dry and wet steam are discussed.

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Considerations in Steam Piping Design for Prevention of an Acoustic Resonance at a Closed Side Branch

Volume 4: Fluid-Structure Interaction ◽

10.1115/pvp2017-65244 ◽

2017 ◽

Author(s):

Ryo Morita ◽

Yuta Uchiyama ◽

Fumio Inada ◽

Shiro Takahashi

Keyword(s):

Liquid Phase ◽

Liquid Film ◽

Acoustic Resonance ◽

Side Branch ◽

Steam Flow ◽

Vortex Generation ◽

Wet Steam ◽

Structural Vibrations ◽

Resonant Amplitude ◽

Flow Experiments

Flow-induced acoustic resonances in piping with closed side branches or T-junctions are one of the causes of severe structural vibrations, which sometimes cause fatigue damage to piping and components in a power plant and many engineering applications. In this paper, on the basis of the results of steam flow experiments and calculations, the effects of the liquid phase on the flow-induced acoustic resonance at closed side branches in the steam flow piping of BWRs are described, and some suggestions for the steam piping design of BWRs are also given. The liquid phase in a steam flow forms droplets or liquid film, which may affect the amplitude, frequency and critical Strouhal number of the resonance. From the results of wet steam experiments and CFD calculations, we have found that in some cases the wetness of the steam flow may decrease the resonant amplitude and change the frequency owing to the interaction of the vortex generation or damping by the existence of the liquid film and droplets. Therefore, for the wet steam piping design of BWR, some suggestions for taking these effects into consideration, under actual BWR steam conditions are described.

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