Numerical analysis on the wall-thinning rate of a bent pipe by liquid droplet impingement erosion

2016 ◽  
Vol 62 ◽  
pp. 306-315 ◽  
Author(s):  
Nobuyuki Fujisawa ◽  
Keitaro Wada ◽  
Takayuki Yamagata
Keyword(s):  
Numerical Analysis ◽  
Liquid Droplet ◽  
Droplet Impingement ◽  
Wall Thinning ◽  
Bent Pipe ◽  
Thinning Rate ◽  
Droplet Impingement Erosion

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.

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.

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

Mechanical Fatigue of Wall Surface Caused by Liquid Droplet Impingement

2010 ◽  
Author(s):  
Manabu Satou
Keyword(s):  
Carbon Steel ◽  
Oxide Layer ◽  
Adhesion Strength ◽  
Adhesive Strength ◽  
Elevated Temperatures ◽  
Liquid Droplet ◽  
Droplet Impingement ◽  
Mechanical Fatigue ◽  
Wall Thinning ◽  
Thinning Rate

Pipe wall thinning caused by water or steam flow was observed associated with oxide layer inside of the pipe. Interaction between oxide formation and corrosion or erosion due to the water or steam flow may be an essential phenomenon of the wall thinning. Thinning rate of the wall therefore depends on the formation of the oxide. In the case of wall thinning caused by liquid droplet impingement (LDI) erosion models, mechanical fatigue of the layers is of interest from estimation of the wall thinning rate. In this paper, from a fundamental point of view, to examine parameters related to adhesion strength of the interface in the model equation of material removal from the wall by multiple droplet impingements, evaluation of adhesion strength between piping material and surface oxide layer was carried out using a laser shock method. Several model oxide layers were prepared at elevated temperatures in oxidizing environments on a carbon steel. Results from the measurements of the adhesive strength of the oxide layer formed on the carbon steel at elevated temperatures, the interface had a comparative strength or less of the yield stress of the carbon steel. It was found that reputation of the loading by laser shots up to 104 times did not affect the adhesive strength so far. A kinetic modeling of the wall thinning caused by the LDI was suggested higher cycle mechanical fatigue.

Sign in / Sign up

Export Citation Format

Share Document