Investigation of Particle Size Effects on Solid Particle Erosion of Elbows in Series for Liquid-Solid Flows

2021 ◽  
Author(s):  
Yeshwanthraj Rajkumar ◽  
Soroor Karimi ◽  
Siamack A. Shirazi

Abstract The entrainment of solid particles within the produced fluids can cause solid particle erosion by impacting the piping of production and transportation facilities. Liquid dominated flows are commonly encountered in deep water subsea pipelines while producing oil and gas fluids. It is of great importance to predict the erosion pattern and magnitude for elbows in series in liquid-solid flows as in the oil and gas productions, liquids tends to produce more solid particles compared to gas-solid flows. In the current work, erosion of elbows in series for different particle sizes are investigated by using computational fluid dynamics (CFD) and compare the erosion pattern results with the results of paint removal experiments using a 76.2 mm diameter acrylic elbows, qualitatively. CFD simulations have been performed to study the particle size effects on erosion using Reynolds stress turbulence model (RSM) and Low-Reynolds number K-ε model. Grid refinement studies have been performed and particles are rebounded at the particle radius to accurately examine the effects of particle sizes on solid particle erosion of these elbows. The CFD results shows that significant erosion is observed at the inner wall of the first elbow for larger particles, and the maximum erosion can be seen towards the end of the second elbow for 300 μm particle size.

Author(s):  
Risa Okita ◽  
Yongli Zhang ◽  
Brenton S. McLaury ◽  
Siamack A. Shirazi ◽  
Edmund F. Rybicki

Although solid particle erosion has been examined extensively in the literature for dry gas and vacuum conditions, several parameters affecting solid particle erosion in liquids are not fully understood and need additional investigation. In this investigation, erosion ratios of two materials have been measured in gas and also in liquids with various liquid viscosities and abrasive particle sizes and shapes. Solid particle erosion ratios for aluminum 6061-T6 and 316 stainless steel have been measured for a direct impingement flow condition using a submerged jet geometry, with liquid viscosities of 1, 10, 25, and 50 cP. Sharp and rounded sand particles with average sizes of 20, 150, and 300 μm, as well as spherical glass beads with average sizes of 50, 150 and 350 μm, were used as abrasives. To make comparisons of erosion in gas and liquids, erosion ratios of the same materials in air were measured for sands and glass beads with the particle sizes of 150 and 300 μm. Based on these erosion measurements in gas and liquids, several important observations were made: (1) Particle size did not affect the erosion magnitude for gas while it did for viscous liquids. (2) Although aluminum and stainless steel have significant differences in hardness and material characteristics, the mass losses of these materials were nearly the same for the same mass of impacting particles in both liquid and gas. (3) The most important observation from these erosion tests is that the shape of the particles did not significantly affect the trend of erosion results as liquid viscosity varied. This has an important implication on particle trajectory modeling where it is generally assumed that particles are spherical in shape. Additionally, the particle velocities measured with the Laser Doppler Velocimetry (LDV) near the wall were incorporated into the erosion equations to predict the erosion ratio in liquid for each test condition. The calculated erosion ratios are compared to the measured erosion ratios for the liquid case. The calculated results agree with the trend of the experimental data.


Author(s):  
G. Haider ◽  
A. Asgharpour ◽  
J. Zhang ◽  
S. A. Shirazi

Abstract During production of oil and gas from wells, solid particles such as removed scales or sand may accompany petroleum fluids. These particles present in this multiphase flow can impact inner walls of transportation infrastructure (straight pipelines, elbows, T-junctions, flow meters, and reducers) multiple times. These repeated impacts degrades the inner walls of piping and as a result, reduce wall thickness occur. This is known as solid particle erosion, which is a complex phenomenon involving multiple contributing factors. Prediction of erosion rates and location of maximum erosion are crucial from both operations and safety perspective. Various mechanistic and empirical solid particle erosion models are available in literature for this purpose. The majority of these models require particle impact speed and impact angle to model erosion. Furthermore, due to complex geometric shapes of process equipment, these solid particles can impact and rebound from walls in a random manner with varying speeds and angles. Hence, this rebound characteristic is an important factor in solid particle erosion modeling which cannot be done in a deterministic sense. This challenge has not been addressed in literature satisfactorily. This study uses experimental data to model particle rebound characteristics stochastically. Experimental setup consists of a nozzle and specimen, which are aligned at different angles so particles impact the specimen at various angles. Information regarding particle impact velocities before and after the impacts are obtained through Particle Tracking Velocimetry (PTV) technique. Distributions of normal and tangential components of particle velocities were determined experimentally. Furthermore, spread or dispersion in these velocity components due to randomness is quantified. Finally, based on these experimental observations, a stochastic rebound model based on normal and tangential coefficients of restitutions is developed and Computational Fluid Dynamics (CFD) studies were conducted to validate this model. The model predictions are compared with experimental data for elbows in series. It is found that the rebound model has a great influence on erosion prediction of both first and second elbows especially where subsequent particle impacts are expected.


Author(s):  
Yeshwanth R. Rajkumar ◽  
Siamack A. Shirazi ◽  
Soroor Karimi

Abstract Solid particle erosion is one of the most commonly encountered problems faced by the oil and gas industries during production and transportation processes. The severity of solid particle erosion is affected by multitude of factors such as particle properties, fluid flow properties and flow geometry, flow regime, and target material properties. The present work investigates the effect of particle size on solid particle erosion in gas flows. Sharp quartz particles with nominal sizes of 75, 150, 300 and 600 μm are used in this work. Particle Image Velocimeter (PIV) is used to measure the particles velocities distributions for various particle flow rates. An average particle velocity of 24 m/s is used to conduct erosion experiments for various particle sizes and two particle rates on Stainless Steel 316 at two different impact angles of 15 and 90 degrees. Comparison of measurements for two particle flow rates of approximately 0.02% and 0.002% by volumes demonstrates that increased particle flow rate can affect the carrier fluid’s flow field and change particle velocities within the carrying fluid. In the erosion experiments, the magnitude of erosion ratio increases as there is an increase in particle size. A preliminary erosion model is developed that can be used in CFD simulations of solid particle erosion for various particle sizes.


Author(s):  
Frederic N. Felten

Erosive wear due to solid-particle impact is a complex phenomenon where different parameters are responsible for causing material removal from the metal surface. Some of the most critical parameters regarding the solid particles are the size, density, roundness, and volume concentration. The properties of the carrying fluid (density, dynamic viscosity, bulk modulus…), the geometry of the flow path (straight or deviated), and the surface material properties are also major contributors to the overall severity of the solid-particle erosion process. The intent of this paper is to focus on the impact of the flow path geometry on surface erosion for a specific carrier fluid, flow rate, sand type and sand-volume concentration. A numerical approach using the commercial CFD code FLUENT is applied to investigate the solid particle erosion in two 90° pipe elbows mounted in series. The distance between the two elbows is varied, as is the angle between them. A total of 16 cases are analyzed numerically. The relationships between the parameters pertinent to the two elbows and the erosion pattern, erosion intensity, and location of maximum erosion are presented. Prior to the analyses for the two elbows mounted in series, an in-depth validation effort for a single elbow geometry is undertaken to determine the appropriate mesh requirement, turbulence model, and to calibrate the inputs to the erosion model.


Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 921
Author(s):  
Alicja Krella

Due to the increasing maintenance costs of hydraulic machines related to the damages caused by cavitation erosion and/or erosion of solid particles, as well as in tribological connections, surface protection of these components is very important. Up to now, numerous investigations of resistance of coatings, mainly nitride coatings, such as CrN, TiN, TiCN, (Ti,Cr)N coatings and multilayer TiN/Ti, ZrN/CrN and TN/(Ti,Al)N coatings, produced by physical vapor deposition (PVD) method using different techniques of deposition, such as magnetron sputtering, arc evaporation or ion plating, to cavitation erosion, solid particle erosion and wear have been made. The results of these investigations, degradation processes and main test devices used are presented in this paper. An effect of deposition of mono- and multi-layer PVD coatings on duration of incubation period, cumulative weight loss and erosion rate, as well as on wear rate and coefficient of friction in tribological tests is discussed. It is shown that PVD coating does not always provide extended incubation time and/or improved resistance to mentioned types of damage. The influence of structure, hardness, residence to plastic deformation and stresses in the coatings on erosion and wear resistance is discussed. In the case of cavitation erosion and solid particle erosion, a limit value of the ratio of hardness (H) to Young’s modulus (E) exists at which the best resistance is gained. In the case of tribological tests, the higher the H/E ratio and the lower the coefficient of friction, the lower the wear rate, but there are also many exceptions.


2018 ◽  
Vol 5 (5) ◽  
pp. 1174-1179 ◽  
Author(s):  
Pingping Song ◽  
Hui Xu ◽  
Bo Yan ◽  
Jin Wang ◽  
Fei Gao ◽  
...  

The electrocatalytic oxidation of ethylene glycol and glycerol in the presence of PtAg NPs catalyst showed a linear decrease with the increasing particle sizes, providing new clues and hypotheses on how quantum confinement phenomena affect the electrocatalytic performances.


Author(s):  
Bijan Mohammadi ◽  
AmirSajjad Khoddami

Solid particle erosion is one of the main failure mechanisms of a compressor blade. Thus, characterization of this damage mode is very important in life assessment of the compressor. Since experimental study of solid particle erosion needs special methods and equipment, it is necessary to develop erosion computer models. This study presents a coupled temperature–displacement finite element model to investigate damage of a compressor blade due to multiple solid particles erosion. To decrease the computational cost, a representative volume element technique is introduced to simulate simultaneous impact of multiple particles. Blade has been made of Ti-6Al-4V, a ductile titanium-based alloy, which is impacted by alumina particles. Erosion finite element modeling is assumed as a micro-scale impact problem and Johnson–Cook constitutive equations are used to describe Ti-6Al-4V erosive behavior. In regard to a wide variation range in thermal conditions all over the compressor, it is divided into three parts (first stages, middle stages, and last stages) in which each part has an average temperature. Effective parameters on erosive behavior of the blade alloy, such as impact angle, particles velocity, and particles size are studied in these three temperatures. Results show that middle stages are the most critical sites of the compressor in terms of erosion damage. An exponential relation is observed between erosion rate and particles velocity. The dependency of erosion rate on size of particles at high temperatures is indispensable.


Author(s):  
Alireza Asgharpour ◽  
Peyman Zahedi ◽  
Hadi Arabnejad Khanouki ◽  
Siamack A. Shirazi ◽  
Brenton S. McLaury

Solid particle erosion in elbows is of great importance in the pipeline design process. In many situations, elbows are mounted in series with small distances between each other. Due to changes in flow direction and particles concentration after the first elbow, a significant change in erosion magnitude and pattern in the downstream elbows (second elbow) might be expected. The aim of this study is to investigate the solid particle erosion behavior in the second elbow. In the experimental study using a state-of-art ultrasonic technique, erosion magnitudes in two standard 4-inch elbows separated by a distance of 10 pipe diameter have been measured. Experiments have been conducted in single and two-phase flow regimes for different particle sizes and gas and liquid velocities. In most of the cases, the maximum erosion in the second elbow was less than the first elbow, and the erosion pattern in the second elbow was slightly different than the first elbow. Comparison of single and two-phase flow results for both elbows revealed that in two-phase flow regime a major reduction in erosion magnitude happens as a results of the presence of liquid in the pipe. Additionally, for further considerations, the experimental conditions have been simulated numerically using ANSYS FLUENT software. Simulations have been performed for different mesh grids and turbulence models to examine how they influence the erosion in the second elbow as both can affect the particles trajectories. The accuracy of the numerical results are evaluated with available experimental data. For most of the cases, the erosion predictions are in a good agreement with experimental results. For both elbows by increasing the gas velocity and particle size, the maximum erosion increased.


Sign in / Sign up

Export Citation Format

Share Document