scholarly journals Modeling of Liquid Droplet Impingement onto Ti-6Al-4V Substrate

2019 ◽  
Author(s):  
Mason Marzbali ◽  
Ali Dolatabadi
Keyword(s):  
Liquid Droplet ◽  
Droplet Impingement

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.

Influence of surface roughness on liquid droplet impingement erosion

Wear ◽  
2019 ◽  
Vol 432-433 ◽  
pp. 202955 ◽  
Author(s):  
K. Fujisawa ◽  
M. Ohki ◽  
N. Fujisawa
Keyword(s):  
Surface Roughness ◽  
Liquid Droplet ◽  
Droplet Impingement ◽  
Droplet Impingement Erosion

Parametric Investigation on the Effect Factors for Liquid Droplet Impingement Erosion

2011 ◽  
Author(s):  
Rui Li ◽  
Hisashi Ninokata ◽  
Michitsugu Mori
Keyword(s):  
Power Plants ◽  
Erosion Rate ◽  
Structural Integrity ◽  
Volume Fraction ◽  
Liquid Droplet ◽  
Droplet Velocity ◽  
Life Extension ◽  
Droplet Impingement ◽  
Pipe Surface ◽  
Bent Pipe

Liquid droplet impingement (LDI) erosion could be regarded to be one of the major causes of unexpected troubles occasionally occurred in the inner bent pipe surface. Evaluating the LDI erosion is an important topic of the thermal hydraulics and structural integrity in aging and life extension for nuclear power plants safety. In order to investigate the effect of various parameters, such as droplet diameter, droplet velocity and injected droplet number, on the erosion rate induced by LDI, droplet impingement under different conditions are conducted numerically by a two-phase computational approach. Considering the carrier turbulence kinetic energy attenuation due to the involved droplets, numerical simulations have been performed by using two-way vapor-droplet coupled system. This computational fluid model is built up by incompressible Reynolds Averaged Navier-Stoke equations using standard k-ε model and the SIMPLE algorithm, and the numerical droplet model adopts the Lagrangian approach, a general LDI erosion prediction procedure for bent pipe geometry has been performed to supplement an available CFD code. A correlation for the erosion rate in terms of droplet velocity, diameter and volume fraction is purposed for the engineers’ maintenance reference. Based on our computational results, comparison with an available accident data was made to prove that our methodology could be an appropriate way to simulate and predict the bent pipe wall thinning phenomena.

Evaluation of Local Thinning Shape by LDI for Seismic Safety Evaluation of Piping System

2011 ◽  
Author(s):  
Ryo Morita ◽  
Fumio Inada ◽  
Michiya Sakai ◽  
Shin-ichi Matsuura ◽  
Shigenobu Onishi ◽  
...  
Keyword(s):  
Liquid Droplet ◽  
Safety Evaluation ◽  
Piping System ◽  
Flow Conditions ◽  
Droplet Impingement ◽  
Seismic Safety ◽  
Seismic Safety Evaluation ◽  
Droplet Behavior ◽  
Seismic Tests ◽  
The Relationship

For seismic safety evaluation of piping system with local thinning surface by liquid droplet impingement erosion (LDI), hybrid seismic tests were conducted to the piping with a locally-thinned elbow. In this paper, a method for predicting the thinning shape by LDI on the elbow is developed. To determine the thinning shape by LDI, droplet behavior at the elbow is calculated for various flow conditions and geometries. With the calculation of the collision point and velocity for each droplet, collision frequency and average collision velocity on the elbow are estimated. Then, the thinning shape on the elbow is determined with the relationship between the flow conditions and thinning rate. Finally, the evaluated thinning shape is compared with an actual LDI case for the validation of the method.

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