C213 Evaluation of Local Wall Thinning of Piping with A Model Based on Liquid Droplet Impingement Accelerated Corrosion

2010 ◽  
Vol 2010.15 (0) ◽  
pp. 351-354
Author(s):  
Hidetoshi Okada ◽  
Shunsuke UCHIDA ◽  
Masanori Naitoh ◽  
Yasushi Uehara ◽  
Seiichi Koshizuka
Keyword(s):  
Liquid Droplet ◽  
Droplet Impingement ◽  
Accelerated Corrosion ◽  
Model Based ◽  
Wall Thinning ◽  
Local Wall Thinning

Potential Difference Distribution on Flat Plate Around Semi-Ellipsoidal Thinning on the Back Surface

2014 ◽  
Author(s):  
Naoya Tada ◽  
Makoto Uchida ◽  
Manabu Nohara
Keyword(s):  
Flat Plate ◽  
Liquid Droplet ◽  
Potential Difference ◽  
Back Surface ◽  
Analysis Method ◽  
Droplet Impingement ◽  
Accelerated Corrosion ◽  
Flow Accelerated Corrosion ◽  
Non Destructive ◽  
Local Wall Thinning

Local wall thinning is one of serious problems in aged power generating plants and is known to occur mainly by Flow Accelerated Corrosion (FAC) and Liquid Droplet Impingement (LDI) erosion. As the thinning grows inside the pipes, it is difficult to detect and evaluate it from the outer surface of pipe. The direct-current potential difference method (DC-PDM) is thought to be a suitable non-destructive technique to monitor the initiation and growth of these damages. In this study, an approximate analysis method of the potential difference around a semi-ellipsoidal thinning on the back surface of flat plate is presented and the accuracy is discussed based on the results obtained by the finite element analyses.

Studies on Flow and Pipe Wall Thinning and the Reduction in the Downstream of Orifice Nozzle

2011 ◽  
Author(s):  
Toshihiko Shakouchi ◽  
Takayuki Suzuki ◽  
Hideki Yuya ◽  
Masaki Naruse ◽  
Koichi Tsujimoto ◽  
...  
Keyword(s):  
Cavitation Erosion ◽  
Pipe Wall ◽  
Liquid Droplet ◽  
Piping System ◽  
Droplet Impingement ◽  
Accelerated Corrosion ◽  
Wall Thinning ◽  
System 1 ◽  
Flow Accelerated Corrosion ◽  
Droplet Impingement Erosion

In a piping system of power plant, pipe wall thinning by Flow Accelerated Corrosion, FAC, Liquid Droplet Impingement Erosion, LDI, and Cavitation Erosion, C/E, are very serious problems because they give a damage and lead to the destructtion of the piping system[1]–[6]. In this study, the pipe wall thinning by FAC in the downstream of orifice nozzle, flow meter, is examined. Namely, the characteristics of FAC, generation mechanism, and prediction of the thinning and the reduction are made clear by experimental analysis. As a results, it was made clear that (1) the thinning is occurred mainly according to the size of the pressure fluctuation p′ on the pipe wall and the thinning can be estimated by it, and (2) the suppression of p′ can be realized by replacing the orifice to a taper shaped one having an angle to the upstream.

Attenuation of wall-thinning rate in deep erosion by liquid droplet impingement

2016 ◽  
Vol 88 ◽  
pp. 151-157 ◽  
Author(s):  
Nobuyuki Fujisawa ◽  
Takayuki Yamagata ◽  
Keitaro Wada
Keyword(s):  
Liquid Droplet ◽  
Droplet Impingement ◽  
Wall Thinning ◽  
Thinning Rate

Buckling Strength Evaluation of Locally Wall Thinning Elbow

2017 ◽  
Author(s):  
Michiya Sakai ◽  
Shinichi Matsuura ◽  
Ryo Morita ◽  
Fumio Inada ◽  
Shigenobu Onishi
Keyword(s):  
Liquid Droplet ◽  
Electric Power Industry ◽  
Central Research Institute ◽  
Piping System ◽  
Central Research ◽  
Droplet Impingement ◽  
Seismic Motion ◽  
Wall Thinning ◽  
Out Of Plane ◽  
Test Result

In a previous study [1], the seismic behavior of a piping system with local thinning elbow caused by liquid droplet impingement erosion (LDI) was evaluated using hybrid seismic testing method in Central Research Institute of Electric Power Industry (CRIEPI). In those studies, torsional buckling and wrinkles occurred at locally wall thinning elbow under large amplitude seismic motion of eight times the design basis earthquake based on the allowable stress level. It was concluded that buckling should be considered as a failure mode. In this study, the torsion buckling under out-of-plane bending of locally wall thinning elbows could be demonstrated by finite element analyses. Torsion buckling deformation agreed well with test result and the critical buckling deformation was clarified by comparing parameter analyses. The buckling formula was proposed to prevent the torsion buckling of locally wall thinning elbow.

Detection of the Crack Initiation by Means of AE Method Under Low Cycle Fatigue of Elbow Pipe Having Local Wall Thinning

2010 ◽  
Author(s):  
Naoya Kasai ◽  
Kotoji Ando ◽  
Maki Nishio ◽  
Yoshio Urabe ◽  
Koji Takahashi
Keyword(s):  
Crack Initiation ◽  
Low Cycle Fatigue ◽  
Axial Strain ◽  
Wide Band ◽  
Fatigue Tests ◽  
Crack Growth Behavior ◽  
Cycle Fatigue ◽  
Accelerated Corrosion ◽  
Wall Thinning ◽  
Local Wall Thinning

This paper describes the detectability of the crack initiation by means of the AE method under low cycle fatigue of the elbow pipe having local wall thinning to clarify the crack growth behavior for the pipes. Elbow specimens having local wall thinning were prepared, and local wall thinning due to flow accelerated corrosion was simulated by machined pipe wall thinning. Low cycle fatigue tests for the specimens were then carried out. AE method during low cycle fatigue tests was conducted to evaluate the crack initiation and location. In AE measurement, wide band AE sensors of 5mm in diameter were used to attach to the convex surfaces of the specimens. The circumference and axial strain of the specimens and the cross head displacement were also stored to the digital AE system signal. As a result, it is clear that the AE signals indicated the crack initiation in small circumference strain.

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