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

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.

Expansion of Multi-Purpose Steam Facility and Application to Acoustic Resonance in a Closed Side Branch Investigating Effects of Static Pressure Under Wet Steam Flow

2017 ◽  
Author(s):  
Yuta Uchiyama ◽  
Ryo Morita
Keyword(s):  
Power Plants ◽  
Static Pressure ◽  
Acoustic Resonance ◽  
Side Branch ◽  
Steam Flow ◽  
Structural Vibration ◽  
Test Facility ◽  
Wet Steam ◽  
Single Side ◽  
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.

Instrumentation for wet steam

2004 ◽  
Vol 218 (8) ◽  
pp. 811-842 ◽  
Author(s):  
A Kleitz ◽  
J M Dorey
Keyword(s):  
Liquid Phase ◽  
Liquid Film ◽  
Direct Determination ◽  
Dispersed Phase ◽  
Wet Steam ◽  
Turbine Performance ◽  
Chemical Measurements ◽  
Formation And Evolution

This paper is devoted to the measuring methods and instrumentation used in the wet-steam area for both aerodynamics measurements (pressure, temperature and velocity) taking into account the interaction between the vapour and the liquid phase, and the characterization of the liquid phase itself (dispersed phase and liquid film). The development of suitable instrumentation is an important part in understanding the formation and evolution of the liquid phase but is now more and more oriented towards practical industrial concerns, such as the direct determination of turbine performance by measuring exhaust wetness or chemical measurements relating to erosion in the transition zone inside the turbine. Emphasis has been given to techniques suitable for use in actual turbines.

Liquid film and droplet stability consideration as applied to wet steam flow

1981 ◽  
Vol 47 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Frederic G. Hammitt ◽  
Stefan Krzeczkowski ◽  
Jerzy Krzyżanowski
Keyword(s):  
Liquid Film ◽  
Steam Flow ◽  
Wet Steam ◽  
Droplet Stability ◽  
Wet Steam Flow ◽  
Stability Consideration

Experimental Evaluation of Resonance Frequency at Branch Section in Each Dry and Wet Steam Flow

2013 ◽  
Author(s):  
Yuta Uchiyama ◽  
Ryo Morita
Keyword(s):  
Resonance Frequency ◽  
Sound Speed ◽  
Power Plants ◽  
Acoustic Resonance ◽  
Dominant Frequency ◽  
Steam Flow ◽  
Theoretical Equation ◽  
Piping System ◽  
Wet Steam ◽  
Piping Systems

Flow-induced acoustic resonances of piping system containing closed side-branches are sometimes encountered in power plants. In U.S. NPP, the steam dryer had been damaged by high cycle fatigue due to acoustic-induced vibration under a power uprating condition. The steam piping systems of actual power plants often have nearly saturated wet steam condition. Resonance frequency at branch section is one of important factors for evaluation and prediction of acoustic resonance. However, the resonance frequency in steam condition could not be estimated by using theoretical equation since the end correction under steam condition is not clarified. In addition, sound speed in wet steam, which is evaluated by theoretical isentropic equation, may be different from practical sound speed in wet steam. Although there are several previous studies about acoustic resonance, most of them are not steam flow but air flow. In the present study, the end correction in each dry and wet steam and sound speed of wet steam was evaluated from experimental results of dominant frequency of fluctuating pressure. As a result, method for predicting resonance frequency by using theoretical equation in each dry and wet steam condition was proposed.

scholarly journals A study of the electrostatic charge of the coarse water droplets

2021 ◽  
Vol 345 ◽  
pp. 00003
Author(s):  
Ondřej Bartoš ◽  
Václav Peter
Keyword(s):  
Liquid Phase ◽  
Wind Tunnel ◽  
Liquid Film ◽  
Thin Liquid Film ◽  
Electrical Current ◽  
Electrostatic Charge ◽  
Steam Turbines ◽  
Wet Steam ◽  
Water Droplets ◽  
Charging Mechanism

The aim of this paper is introduce the results of a measurement of the electrostatic charge of water droplets during wet steam expansion. The analysis of the charge origin was done. The achieved result shows that there is not a significant charging mechanism for the fine droplets. The dependence between the specific electrical current and the amount of liquid phase collected by the probe was found. Some models were studied to determine the origin of the electrical current. Finally a model was proposed, where the el. current is generated by the disruption of thin liquid film on the surface of the probe. The charging model was later applied for the measurement of the liquid film disruption in the new wind tunnel designed for the simulation of the flow field in the steam turbines. The measurement was performed with the air as a flowing medium and two modal droplets size distribution was found.

Sign in / Sign up

Export Citation Format

Share Document