流れ加速型腐食への乱流場速度変動周波数特性の依存性調査

抄録

Flow-Accelerated Corrosion (FAC) causes a wide range of pipe wall thinning in nuclear power plants, therefore there is a high possibility that FAC causes piping rupture and wholesale coolant leak. In this study, accelerated pipe wall thinning experiment using benzoic acid as thinning wall and flow visualization experiment by particle image velocimetry using sodium iodide solution and channel wall made of acrylic resin were conducted to explore the possibility that the frequency characteristic of turbulent velocity fluctuation influences flow-accelerated corrosion downstream of an orifice. As a result, power spectral density (PSD) of low-frequency velocity fluctuation parallel to the channel wall at the maximum wall thinning rate area was notably larger than that at moderate wall thinning area although the intensity of velocity fluctuation perpendicular to the wall and Reynolds stress were larger in entire frequency range.