F081003 Latest Technical Knowledge on the Pipe Wall Thinning Management : (3) Latest Study on the Liquid Droplet Impingement Erosion

2012 ◽  
Vol 2012 (0) ◽  
pp. _F081003-1-_F081003-3
Author(s):  
Nobuyuki FUJISAWA ◽  
Ryo MORITA ◽  
Akira NAKAMURA ◽  
Takayuki YAMAGATA
Keyword(s):  
Pipe Wall ◽  
Liquid Droplet ◽  
Technical Knowledge ◽  
Droplet Impingement ◽  
Wall Thinning ◽  
Droplet Impingement Erosion

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.

State of the Art Study for the Basis of Pipe Wall Thinning Management in Japan

2013 ◽  
Author(s):  
Fumio Inada ◽  
Yutaka Watanabe ◽  
Taku Ohira ◽  
Akira Nakamura
Keyword(s):  
Pipe Wall ◽  
Liquid Droplet ◽  
Technical Knowledge ◽  
Research Committee ◽  
Accelerated Corrosion ◽  
Inspection Method ◽  
The Road ◽  
Road Map ◽  
Wall Thinning ◽  
New Findings

Main committee of Power Generation Facility Code (MCPGFC) of Japan Society of Mechanical Engineers (JSME) established rules to manage pipe wall thinning on 2005–2006, and they also made a roadmap in 2007 to enhance pipe wall thinning management rules. Research Committee on Application of New Findings and Technology to Improve Pipe-Wall-Thinning Management, which was conducted from April 2010 to March 2012 summarized the new draft technical knowledge of the major phenomena of pipe wall thinning, that is, flow accelerated corrosion and liquid droplet impingement erosion as well as new inspection method. In this report, the new technical knowledge is described. The achievement situation of the road map made in 2007 was evaluated, and the studies required in future were considered.

Development of a Wall Thinning Rate Model for Liquid Droplet Impingement Erosion

2012 ◽  
Author(s):  
Ryo Morita ◽  
Yuta Uchiyama
Keyword(s):  
Power Plant ◽  
High Speed ◽  
Liquid Droplet ◽  
Steam Flow ◽  
Wet Steam ◽  
Droplet Impingement ◽  
Wall Thinning ◽  
Wet Steam Flow ◽  
Thinning Rate ◽  
Droplet Impingement Erosion

Liquid droplet impingement erosion (LDI) is defined as an erosion phenomenon caused by high-speed droplet attack in a wet steam flow. Pipe wall thinning due to LDI is sometimes observed in a steam piping system of a power plant. In this study, for more realistic LDI evaluation in the power plant, we conducted LDI experiments in wet steam flow with steam apparatus, and tried to develop a new thinning rate prediction model (LDI model). High speed wet steam flow simulating the actual plant condition was employed in the experiments. As a result, the cushioning effect of liquid film on a material surface was observed and was incorporated into LDI model as a empirical equation with fluid parameter.

Evaluation method for pipe wall thinning due to liquid droplet impingement

2013 ◽  
Vol 264 ◽  
pp. 195-202 ◽  
Author(s):  
M. Naitoh ◽  
H. Okada ◽  
S. Uchida ◽  
H. Yugo ◽  
S. Koshizuka
Keyword(s):  
Evaluation Method ◽  
Pipe Wall ◽  
Liquid Droplet ◽  
Droplet Impingement ◽  
Wall Thinning

Numerical Analysis of Influence of Roughness of Material Surface on High-Speed Liquid Droplet Impingement

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Hirotoshi Sasaki ◽  
Yuka Iga
Keyword(s):  
Numerical Analysis ◽  
High Speed ◽  
Erosion Rate ◽  
Liquid Droplet ◽  
Material Surface ◽  
Liquid Droplets ◽  
Fluid Machinery ◽  
Droplet Impingement ◽  
Surface Liquid ◽  
Droplet Impingement Erosion

This study explains why the deep erosion pits are formed in liquid droplet impingement erosion even though the droplets uniformly impinge on the entire material surface. Liquid droplet impingement erosion occurs in fluid machinery on which droplets impinge at high speed. In the process of erosion, the material surface becomes completely roughened by erosion pits. In addition, most material surface is not completely smooth and has some degree of initial roughness from manufacturing and processing and so on. In this study, to consider the influence of the roughness on the material surface under droplet impingement, a numerical analysis of droplets impinging on the material surface with a single wedge and a single bump was conducted with changing offsets between the droplet impingement centers and the roughness centers on each a wedge bottom and a bump top. As results, two mechanisms are predicted from the present numerical results: the erosion rate accelerates and transitions from the incubation stage to the acceleration stage once roughness occurs on the material surface; the other is that deep erosion pits are formed even in the case of liquid droplets impinging uniformly on the entire material surface.

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