Abstract The velocity field behind an orifice in a circular pipe is studied by PIV measurement u nder the influence of curved swirling flow to elucidate the asymmetric pipe-wall thinning pheno menon behind an orifice. The experiment is carried out in a closed water tunnel at Reynolds numb er Re = 19,000. The stereo PIV measurement of the cross-sectional velocity field in a pipe flow indicates that the flow reattachment occurs on one side of the pipe flow irrespective of the ori fice bias. This is due to th...
英字タイトル:
Influence of Curved Swirling Flow on Mass Transfer Phenomenon behind an Orifice(Velocity Field Measurement by Stereo PIV)

In this paper, experimental and numerical studies are carried out to understand the pipe-wall thinning caused by the flow accelerated corrosion behind an orifice in a circular pipe. The measurement of mass transfer coefficient is carrie d out using a wall material of benzoic acid in a water flow, which allows the measurement of mass transfer behind the orifice in a circular pipe at Schmidt number 300 and 700, which is comparatively close to the actual condition in the prototype pipeline of nuclear power pl...
英字タイトル:
Study on Mass Transfer Phenomenon behind an Orifice in a Circular Pipe - Effect of Schmidt Number -

In this paper, a comparative study of the pipe-wall thinning prediction with existing experimental data is carried out for some typical cases of flow accelerated corrosion of carbon steel. The numerical model tested in this study is the pipe-wall thinning model based on the standard k-εmodel of turbulence with the modification of high-Schmidt-number effect. The comparative study is carried out for the straight pipe flow, the pipe flow behind an orifice and the pipe flow behind a long elbow combined wit...
英字タイトル:
Investigation on Pipe-wall Thinning Prediction by Flow Accelerated Corrosion

In this paper, pipe-wall thinning phenomenon behind an orifice in a circular pipe is studied by measuring the mass transfer coefficient along the pipe wall by naphthalene sublimation method. An attention is placed on the asymmetrical pipe-wall thinning phenomenon behind an orifice under the influence of swirling flow and allowable orifice bias. The present measurement indicates that the mass transfer coefficient becomes asymmetric about the pipe axis behind the orifice in certain combinations of swirl...
英字タイトル:
Investigation on Pipe-wall Thinning by Flow-accelerated Corrosion (Mass Transfer Phenomenon by Combined Effect of Swirling Flow and Orifice Bias)

The liquid droplet impinging erosion has been a topic of interests related to the maintenance of highly-aged nuclear power plant. However, there exists very few erosion data for small liquid droplets having an order of tens of micrometer in diameter, which is often encountered in prototype pipelines for nuclear power plant. In the present paper, the liquid droplet impinging erosion is investigated by high-speed spray to study the erosion rate of aluminum material with respect to droplet parameters, su...
英字タイトル:
Investigation on Liquid Droplet Impinging Erosion (Evaluation of erosion rate by high-speed spray)

The erosion rate of aluminum material by liquid droplet impingement erosion is studied by using high speed spray. In order to propose an accurate prediction method, a new experimental data are obtained by using the spray erosion larger than the scale of specimen, which allo ws a constant erosion rate, while it is not for the previous method. The new experimental data shows that the erosion rate is proportiona l to the power of 7 of the droplet velocity, which results in a highly accurate prediction method...
英字タイトル:
Investigation on Liquid Droplet Impinging Erosion by High-Speed Spray(Evaluation of Erosion Rate and Its Velocity Dependency)