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.

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.

Development of Pipe Wall Thinning Evaluation Method and Prediction Tool

2013 ◽  
Author(s):  
Kimitoshi Yoneda ◽  
Ryo Morita ◽  
Kazutoshi Fujiwara ◽  
Fumio Inada
Keyword(s):  
Power Plants ◽  
Evaluation Method ◽  
Pipe Wall ◽  
Liquid Droplet ◽  
Thickness Measurement ◽  
Management Tool ◽  
Plant Management ◽  
Piping System ◽  
Wall Thinning ◽  
Thinning Rate

Flow accelerated corrosion (FAC) and liquid droplet impingement erosion (LDI) are the main pipe wall thinning phenomena in piping system of power plants in Japan. Authors have promoted the development of prediction method to evaluate local thinning trend by FAC/LDI. To apply the method to pipe wall thinning management in power plants, it is required to be transformed into practical tools for easy usage. In Japan, discussion is being made to considerate the introduction of prediction tools into wall thinning management based on wall thickness measurement at present. Authors have simplified their FAC/LDI models to predict wall thinning trend one-dimensionally along piping layout, and applied to actual thinning data of power plants. With PWR’s FAC data and BWR’s LDI data, maximum thinning rate for each pipe elements were roughly predictable with considerable accuracy. Especially for high thinning rate data, which is important in plant management, the model was able to evaluate within the factor of 2. By installing this model, prediction software “FALSET” was developed, equipped with practical functions for the management. With the further verification and improvement of each function, there are prospects for this software to be utilized as a management tool in power plants.

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.

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