scholarly journals A New Method for Predicting Erosion Damage of Suddenly Contracted Pipe Impacted by Particle Cluster via CFD-DEM

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1858 ◽  
Author(s):  
Jiarui Cheng ◽  
Yihua Dou ◽  
Ningsheng Zhang ◽  
Zhen Li ◽  
Zhiguo Wang
Keyword(s):  
Erosion Rate ◽  
Numerical Study ◽  
Target Surface ◽  
Impact Angle ◽  
Particle Collision ◽  
Particle Cluster ◽  
Interparticle Collision ◽  
Velocity Decay ◽  
Discrete Element Methods ◽  
The Impact

A numerical study on the erosion of particle clusters in an abrupt pipe was conducted by means of the combined computational fluid dynamics (CFD) and discrete element methods (DEM). Furthermore, a particle-wall extrusion model and a criterion for judging particle collision interference were developed to classify and calculate the erosion rate caused by different interparticle collision mechanisms in a cluster. Meanwhile, a full-scale pipe flow experiment was conducted to confirm the effect of a particle cluster on the erosion rate and to verify the calculated results. The reducing wall was made of super 13Cr stainless steel materials and the round ceramsite as an impact particle was 0.65 mm in diameter and 1850 kg/m3 in density. The results included an erosion depth, particle-wall contact parameters, and a velocity decay rate of colliding particles along the radial direction at the target surface. Subsequently, the effect of interparticle collision mechanisms on particle cluster erosion was discussed. The calculated results demonstrate that collision interference between particles during one cluster impact was more likely to appear on the surface with large particle impact angles. This collision process between the rebounded particles and the following particles not only consumed the kinetic energy but also changed the impact angle of the following particles.

scholarly journals Characterization of the Solid Particle Erosion of the Sealing Surface Materials of a Ball Valve

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 263
Author(s):  
Donghua Peng ◽  
Shaohua Dong ◽  
Zhiqiang Wang ◽  
Dongying Wang ◽  
Yinuo Chen ◽  
...  
Keyword(s):  
Erosion Rate ◽  
Cfd Simulation ◽  
Two Phase Flow ◽  
Simulation Analysis ◽  
Impact Angle ◽  
Ball Valve ◽  
Phase Flow ◽  
Two Phase ◽  
Valve Sealing ◽  
The Impact

The ball valve is an essential piece of equipment in an oil and gas pipeline. The sand particles transported through the pipeline can cause erosion and wear to the ball valve, thus causing it to fail, leading to serious safety hazards. In this paper, the self-designed erosion experiment method was combined with computational fluid dynamics (CFD), while the Euler-Lagrange method was also introduced to optimize the Oka erosion model and Ford particle-wall rebound model. The erosion mechanism and characteristics of the ball valve sealing surface in gas-solid two-phase flow were simulated, while the erosion condition of the specimen was analyzed and compared when exposed to different factors, such as different particle velocities, impact angle, particle size, and specimen materials. The experimental data conformed well to the CFD erosion simulation data, verifying the accuracy of the CFD simulation analysis. The results indicated that the worn surface was caused by various wear mechanisms, while a “stagnation zone” was identified at the center of the specimen. The maximum erosion area, which was U-shaped, was also located at the center. The erosion rate increased in conjunction with an increase in the particle velocity and size, both of which failed to affect the erosion pattern. The erosion rate initially increased, after which it decreased with the impact angle, reaching the maximum value at an impact angle of 30°. This paper summarizes the erosion failure mechanism and characteristics in gas–solid two-phase flow and provides both technical support and a theoretical basis for the on-site maintenance of essential vulnerable parts in the pipeline, such as ball valves.

scholarly journals High Temperature Coatings for Protection Against Turbine Deterioration

1993 ◽  
Author(s):  
W. Tabakoff ◽  
M. Metwally ◽  
A. Hamed
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
High Temperatures ◽  
Erosion Rate ◽  
Wind Erosion ◽  
Protective Coatings ◽  
Impact Angle ◽  
Steam Turbines ◽  
Erosion Behavior ◽  
The Impact

In this research, an investigation was conducted to study the fly ash particles associated with the erosion behavior of alloys and coatings which are widely used in gas and steam turbines. The erosion behavior of many alloys and protective coatings has been investigated experimentally at high temperatures using a specially designed wind erosion tunnel. The erosion results show the effect of velocity, temperature and the impact angle on the erosion rate.

Optimization of erosion wears of Al–Mg–Si–Cu–SiC composite produced by the PM method

2020 ◽  
Vol 39 (1) ◽  
pp. 63-75
Author(s):  
Rajesh Kumar Behera ◽  
Birajendu Prasad Samal ◽  
Sarat Chandra Panigrahi ◽  
Sudhansu Ranjan Das
Keyword(s):  
Design Of Experiments ◽  
Impact Velocity ◽  
Metal Matrix ◽  
Erosion Rate ◽  
Desirability Function ◽  
Impact Angle ◽  
Experimental Results ◽  
Function Approach ◽  
The Impact ◽  
Desirability Function Approach

Abstract Metal matrix composites are expanding their range every day due to their various industrial applications in manufacturing sectors, to attain high performance and favorable characteristics such as light weight, more excellent corrosion as well as wear resistance, high specific strength and high temperature-resistance than conventional materials. This study deals with analysis on erosion wear characteristic and corrosion behavior of newly-engineered aluminum metal–matrix composite (Al–0.5Si–0.5Mg–2.5Cu–5SiC) developed by powder metallurgy method. Solid particle erosion test was conducted on the newly developed AMMC product and the execution of design of experiments through Taguchi and statistical techniques demonstrates the feasibility of investigating the erosion characterization and behaviors of the composites. Sixteen set of experimental trials were performed by considering three process parameters (impact angle, stand-off distance, and impact velocity) associated with four levels each. Experimental results in accordance of Taguchi’s orthogonal array design of experiments are analyzed by employing analysis of variance (ANOVA), response surface methodology (RSM) and desirability function approach for analysis, predictive modeling and optimization of erosion rate, respectively. Thereafter, an observation on eroded surface morphology is performed under the influence of impact velocity by employing scanning electron microscope (SEM) to entrench the process. Result shows that, the impact velocity followed by impact angle have significant contribution (80.42 and 8.71%, respectively) in improvement of erosion rate. The methodology proposed in this study collects the experimental results and builds a mathematical model in the domain of interest and optimized the process model. Under the highest desirability (1), desirability-function approach of RSM presented the optimal manufacturing conditions at impact velocity of 18 m/s, stand-off distance of 26 mm and impact angle of 67° with estimated erosion rate of 65.155 mg/kg. The experimental data generated for Al–0.5Si–0.5Mg–2.5Cu–5SiC AMMC will be useful for the industry.

scholarly journals Study on the Influence of Sand Erosion Process on the Wear and Damage of Heat-Treated U75V Rail Steel

2020 ◽  
Vol 143 (8) ◽  
Author(s):  
Kang Shu ◽  
Wen-Jian Wang ◽  
Enrico Meli ◽  
Hao-Hao Ding ◽  
Zhen-Yu Han ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Velocity ◽  
Erosion Rate ◽  
Rail Steel ◽  
Impact Angle ◽  
Sand Particle ◽  
Erosion Wear ◽  
Heat Treated ◽  
Impact Angles ◽  
The Impact

Abstract Usually, rail materials are exactly affected by the erosion of windblown sand in the desert environment. For this reason, the influence of impact angle, particle velocity, and particle size on the erosion wear behavior of the U75V heat-treated rail steel, a material frequently employed in Chinese railways, were studied in this work. The results showed that, with increasing impact angle, the erosion rate increased between 15 deg and 45 deg, decreased between 45 deg and 75 deg, and then increased again between 75 deg and 90 deg. The highest erosion rate occurred at about 45 deg. When the particle velocity increased, the erosion rate increased approximately in a quadratic way. As the sand particle size increased, the erosion rate presented a decreasing trend. During the initial stage of erosion, shear craters, indentation craters, and ploughing craters were the main surface damage features. The shear craters predominated at the impact angle of 45 deg whereas the indentation craters predominated at 90 deg. During the steady-state of erosion, the rail damage was mainly composed of craters, platelets, and cracks. Both the length and depth of craters increased almost linearly with increasing particle velocity, whereas the increased rate of length was significantly higher than that of depth. The length and depth of craters increased with increasing particle size at 90 deg, whereas only the length increased with increasing particle size at 45 deg. The microstructure evolution and the formation mechanism of platelet at low impact angles were different from those at high impact angles. Platelet formation was the main erosion wear mechanism.

FEM Investigation of Phase Transformation in Vibration Assisted Nano Impact Machining by Loose Abrasives (VANILA)

2018 ◽  
Author(s):  
Nick H. Duong ◽  
J. Ma ◽  
Muhammad P. Jahan ◽  
Shuting Lei ◽  
Murali Sundaram
Keyword(s):  
Phase Transformation ◽  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Numerical Study ◽  
Impact Angle ◽  
Machining Parameters ◽  
Phase Volume ◽  
Impact Speed ◽  
Afm Probe ◽  
The Impact

In this paper, a numerical study of a nanomachining process, Vibration Assisted Nano Impact machining by Loose Abrasives (VANILA), has been conducted. In the VANILA process, an atomic force microscope (AFM) is used as a platform and the nano abrasives (diamond particles) are injected in slurry between the silicon workpiece and the vibrating AFM probe. The vibration of the AFM probe generates kinetic energy for the abrasives to impact the silicon workpiece and result in nanoscale material removal. In addition, silicon usually experiences phase transformation when subject to high pressure at nano-scale. The commercial Finite Element Method (FEM) software package Abaqus is employed to simulate the phase transformation experienced by the silicon workpiece in this VANILA process under different machining parameters such as impact speed, impact angle and coefficient of friction between the nano-abrasive and silicon workpiece. It is found that the machining parameters (impact speed, impact angle, and coefficient of friction) have substantial influence on the phase transformation of silicon workpiece in the nanomachining VANILA. Phase volumes for Si-VII, Si-VIII, and Si-X increase as the impact speed increases from 100 m/s to 200 m/s. Phase volume of Si-X increases as the friction coefficient increases. For Si-VII and Si-VIII, the phase volumes decrease as friction coefficient increases from 0.05, 0.3 and 0.5. In addition, the phase volumes for Si-VII, Si-VIII, and Si-X usually increase as the impact angles increases from 20° to 90°. However, for impact speed of 150 m/s and frictional coefficient of 0.05, the Si-VII phase volume increases first as impact angle increases from 20° to 70° and then decreases as the impact angle increases from 70° to 90°.

The JHUAPL Planetary Impact Lab (PIL): Capabilities and initial results

2019 ◽  
Author(s):  
R. Terik Daly ◽  
Olivier S. Barnouin ◽  
Andrew M. Lennon ◽  
Angela M. Stickle ◽  
Emma S. Rainey ◽  
...  
Keyword(s):  
Ambient Pressure ◽  
Cost Savings ◽  
Target Surface ◽  
Impact Angle ◽  
Planetary Science ◽  
Coarse Grained ◽  
Direction Parallel ◽  
Oblique Impacts ◽  
The Impact ◽  
Initial Results

Abstract The Planetary Impact Lab (PIL) at the Johns Hopkins University Applied Physics Laboratory (JHUAPL) includes a single-stage, compressed inert gas gun that can be used for impact experiments. The impact angle can be varied from 15° to 90° with respect to horizontal, a capability which enables oblique impacts into unconsolidated or granular materials (e.g., regolith analogs). The gun currently achieves impact velocities up to 400 m/s, although future enhancements could increase the maximum projectile velocity. Experiments can be done with atmospheric pressures ranging from ambient pressure down to ~75 Pa. The gun uses sabots produced with state-of-the-art additive manufacturing techniques (AM). Several engineering challenges had to be overcome to create a reliable AM sabot; however, AM sabots are ~45% lighter than and provide substantial cost savings over machined sabots. The PIL gun is currently being used to investigate impact processes on sloped coarse-grained surfaces, with application to planetary science and, specifically, rubble-pile asteroids. In contrast to previous studies of impacts onto slopes, we kept the projectile trajectory perpendicular to the target surface, thereby disentangling the effects of oblique impacts from the effects caused by a sloped surface. Initial results show enhanced crater collapse in the sloped target, with most of the collapse occurring in the direction parallel to the surface gradient. Consequently, final craters on sloped targets have smaller volumes and reduced depth-to-diameter ratios.

Fractal Characterization of Slurry Eroded Surfaces at Different Impact Angles

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Abouel-Kasem ◽  
M. A. Al-Bukhaiti ◽  
K. M. Emara ◽  
S. M. Ahmed
Keyword(s):  
Erosion Rate ◽  
Impact Angle ◽  
Oblique Impact ◽  
Slurry Erosion ◽  
Normal Impact ◽  
Power Spectral ◽  
Impact Angles ◽  
The Impact ◽  
The Relationship

In the present work, the topographical images of slurry erosion surfaces at different impact angles were quantified using fractal analysis. The study showed that the variation of fractal value of slope of linearized power spectral density with the impact angle is largely similar to the relationship between the erosion rate and the impact angle. Both the fractal value and erosion rate were maximum at 45 deg and 90 deg for ductile and brittle materials, respectively. It was found also that the variation of fractal values versus the impact angle has a general trend that does not depend on magnification factor. The fractal features to the eroded surfaces along different directions showed high directionality at oblique impact angle and were symmetrical at normal impact.

Experimental Investigation on the Solid Particle Erosion in the Control Stage Nozzles of Steam Turbine

2007 ◽  
Author(s):  
Shunsen Wang ◽  
Guanwei Liu ◽  
Jingru Mao ◽  
Zhenping Feng
Keyword(s):  
Life Cycle ◽  
Steam Turbine ◽  
Solid Particle ◽  
Erosion Rate ◽  
Impact Angle ◽  
Solid Particle Erosion ◽  
Particle Erosion ◽  
Control Stage ◽  
Profile Characteristic ◽  
The Impact

This study is concerned with experiments for the relation of solid particle erosion (SPE) and the nozzle profiles. The exfoliated scale from boiler tubing results in hard particles that erode steam turbine components, especially on the control stage nozzles of high parameters turbine. To characterize SPE, solid particle trajectory is measured using particle image velocimetry (PIV) and its relation with the erosion rate of the nozzle surfaces is correlated. In addition, erosion characteristic of nozzle material is investigated by experiments and results reveal that the erosion rate is directly proportional to the impacting velocity of particles with the power of 2.31 and the maximum erosion rate is taken place at the impact angle of 20–25 degree. Furthermore, 0.5% increase in the erosion rate for every one degree of steam temperature rise is observed in the range of 839K∼883K. The erosion rate of front-loaded nozzle A is 2∼3 times higher than that of conventional design nozzle B. The life cycle of nozzle is determined by the erosion of outlet edge, and the life of nozzle B is about 5 times as long as the life of nozzle A. Based on the relation of erosion rate and nozzle profile characteristic, it can be inferred that a aft-loaded nozzle with a contoured endwall substituting a planar endwall may outperform over other nozzle profiles in anti-SPE, prolonging the life cycle of the nozzle.

Erosion and accretion by cratering impacts on rocky and icy bodies: Formulation of scaling relations for high-speed ejecta

2021 ◽  
Author(s):  
Hidenori Genda ◽  
Ryuki Hyodo
Keyword(s):  
Point Source ◽  
Numerical Simulations ◽  
High Speed ◽  
Scaling Law ◽  
Large Body ◽  
Target Material ◽  
Target Surface ◽  
Impact Angle ◽  
Material Strength ◽  
The Impact

<p>Numerous small bodies inevitably lead to cratering impacts on large planetary bodies during planet formation and evolution. As a consequence of these small impacts, a fraction of the target material escapes from the gravity of the large body, and a fraction of the impactor material accretes onto the target surface, depending on the impact velocities and angles. Here, we study the mass of the high-speed ejecta that escapes from the target gravity by cratering impacts when material strength is neglected. We perform a large number of cratering impact simulations onto a planar rocky and icy targets using the smoothed particle hydrodynamics method. We show that the escape mass of the target material obtained from our numerical simulations agrees with the prediction of a scaling law under a point-source assumption when <em>v</em><sub>imp</sub> > ~ 10 <em>v</em><sub>esc</sub>, where <em>v</em><sub>imp</sub> is the impact velocity and <em>v</em><sub>esc</sub> is the escape velocity of the target. However, we find that the point-source scaling law overestimates the escape mass up to a factor of ~ 70, depending on the impact angle, when <em>v</em><sub>imp</sub> < ~ 10 <em>v</em><sub>esc</sub> (Figure 1). Using data obtained from numerical simulations, we derive a new scaling law for the escape mass of the target material

Sign in / Sign up

Export Citation Format

Share Document