Improvements of Particle Near-Wall Velocity and Erosion Predictions Using a Commercial CFD Code

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Yongli Zhang ◽  
Brenton S. McLaury ◽  
Siamack A. Shirazi
Keyword(s):  
Solid Particle ◽  
Turbulent Velocity ◽  
Particle Impact ◽  
Solid Particle Erosion ◽  
Wall Region ◽  
Wall Function ◽  
Particle Erosion ◽  
Before And After ◽  
Simulation Results ◽  
Near Wall

The determination of a representative particle impacting velocity is an important component in calculating solid particle erosion inside pipe geometry. Currently, most commercial computational fluid dynamics (CFD) codes allow the user to calculate particle trajectories using a Lagrangian approach. Additionally, the CFD codes calculate particle impact velocities with the pipe walls. However, these commercial CFD codes normally use a wall function to simulate the turbulent velocity field in the near-wall region. This wall-function velocity field near the wall can affect the small particle motion in the near-wall region. Furthermore, the CFD codes assume that particles have zero volume when particle impact information is being calculated. In this investigation, particle motions that are simulated using a commercially available CFD code are examined in the near-wall region. Calculated solid particle erosion patterns are compared with experimental data to investigate the accuracy of the models that are being used to calculate particle impacting velocities. While not considered in particle tracking routines in most CFD codes, the turbulent velocity profile in the near-wall region is taken into account in this investigation, and the effect on particle impact velocity is investigated. The simulation results show that the particle impact velocity is affected significantly when near-wall velocity profile is implemented. In addition, the effects of particle size are investigated in the near-wall region of a turbulent flow in a 90 deg sharp bend. A CFD code is modified to account for particle size effects in the near-wall region before and after the particle impact. It is found from the simulations that accounting for the rebound at the particle radius helps avoid nonphysical impacts and reduces the number of impacts by more than one order-of-magnitude for small particles (25 μm) due to turbulent velocity fluctuations. For large particles (256 μm), however, nonphysical impacts are not observed in the simulations. Solid particle erosion is predicted before and after introducing these modifications, and the results are compared with experimental data. It is shown that the near-wall modification and turbulent particle interactions significantly affect the simulation results. Modifications can significantly improve the current CFD-based solid particle erosion modeling.

Simulations of Particle-Wall-Turbulence Interactions, Particle Motion and Erosion in With a Commercial CFD Code

2006 ◽  
Author(s):  
Yongli Zhang ◽  
Brenton S. McLaury ◽  
Siamack A. Shirazi ◽  
Ronnie D. Russell
Keyword(s):  
Solid Particle ◽  
Particle Motion ◽  
Solid Wall ◽  
Turbulent Velocity ◽  
Particle Impact ◽  
Solid Particle Erosion ◽  
Wall Region ◽  
Particle Erosion ◽  
Before And After ◽  
Near Wall

Calculation of a representative particle impacting velocity is an important component in calculating solid particle erosion inside a pipe geometry. Experiences in calculating erosion for solid-gas systems indicate that gases normally do not affect particle motion near a solid wall. However, solid particles that are entrained in a liquid system tend to undergo a considerable momentum exchange before impacting the solid wall. Currently, most commercial CFD codes allow the user to calculate particle trajectories using a Lagrangian approach. Additionally, the CFD codes calculate particle impact velocities with the pipe walls. However, these commercial CFD codes normally use a wall function to simulate the turbulent velocity field in the near wall region. This wall-function velocity field near the wall can affect the small particle motion in the near wall region. Furthermore, the CFD codes assume particles have zero volume when particle impact information is being calculated. In this investigation, particle motions that are simulated using a commercially available CFD code are examined in the near wall region. Calculated solid particle erosion patterns are compared with experimental data to investigate the accuracy of the models that are being used to calculate particle impacting velocities. While not considered in particle tracking routines in most CFD codes, the turbulent velocity profile in the near-wall region is taken into account in this investigation and the effect on particle impact velocity is investigated. The simulation results show that the particle impact velocity is affected significantly when near wall velocity profile is implemented. In addition, effects of particle size are investigated in the near wall region of a turbulent flow in a 90 degree sharp bend. A CFD code is modified to account for particle size effects in the near wall region before and after the particle impact. It is found from the simulations that accounting for the rebound at the particle radius helps avoid non-physical impacts and reduces the number of impacts by more than one order-of-magnitude for small particles (25 μm) due to turbulent velocity fluctuations. For large particles (256 μm), however, non-physical impacts were not observed in the simulations. Solid particle erosion is predicted before and after introducing these modifications and the results are compared with experimental data. It is shown that the near wall modification and turbulent particle interactions significantly affect the simulation results. Modifications can significantly improve the current CFD-based solid particle erosion modeling.

A Statistical Approach for Modeling Stochastic Rebound Characteristics of Solid Particles

2019 ◽  
Author(s):  
G. Haider ◽  
A. Asgharpour ◽  
J. Zhang ◽  
S. A. Shirazi
Keyword(s):  
Experimental Data ◽  
Solid Particle ◽  
Oil And Gas ◽  
Great Influence ◽  
Solid Particles ◽  
Process Equipment ◽  
Particle Impact ◽  
Solid Particle Erosion ◽  
Contributing Factors ◽  
Particle Erosion

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.

Response of CVD Boron Carbide to Repetitive Indentation Cycles to Simulate Solid Particle Impact Erosion Mechanisms

2005 ◽  
Author(s):  
K. Bose ◽  
R. J. K. Wood
Keyword(s):  
Boron Carbide ◽  
Solid Particle ◽  
Time Dependent ◽  
Particle Impact ◽  
Solid Particle Erosion ◽  
Degradation Mechanisms ◽  
Particle Erosion ◽  
Contact Loads ◽  
Erosion Mechanisms ◽  
Impact Erosion

Repetitive nanoindentation tests offer a method to examine the time-dependent degradation mechanisms in coatings. In the case of coated systems for tribological and more specifically for erosion resistant applications, repeated indentation cycles can characterise their durability to repeated erodent impact. This paper reports preliminary observations on the response of 13–18 μm thick CVD boron carbide on tungsten carbide substrates to repetitive indentation cycles, at contact loads similar to those generated in previously reported solid-particle erosion tests on these coatings conducted by this laboratory [1].

Numerical Simulation Study of Erosion for Fracturing Sandblasting in Elbow

2014 ◽  
Vol 1065-1069 ◽  
pp. 1911-1915
Author(s):  
Bao Rui Xu ◽  
Ming Hu Jiang ◽  
Li Xin Zhao ◽  
Fang Tan ◽  
Xiao Guang Zhang
Keyword(s):  
Numerical Simulation ◽  
Solid Particle ◽  
Solid Particle Erosion ◽  
Adjacent Area ◽  
Erosion Wear ◽  
Particle Erosion ◽  
Factors Affecting ◽  
Fluent Software ◽  
Simulation Results ◽  
The Right

Elbow as common components in the gas pipeline fails easily to natural gas carrying solid particle erosion in the process of practical work. From the viewpoint of hydromechanics, the paper analyses the flow field distribution of manifold pressure and gas-solid trajectory by using the Gambit model and Fluent software in view of the right-angle elbow and numerical simulation of the adjacent manifold. The result obtains the situation about the manifold inner wall by the solid particle erosion wear. The simulation results show more intuitively the elbow, the most prone to erosion part in the manifold adjacent area and shape in erosion. Meanwhile, the paper analyses the factors affecting the occurrence and development of erosion.

scholarly journals Predicting Solid Particle Erosion in Multiphase Flow: Challenges and Success Stories (Keynote Paper)

2009 ◽  
Author(s):  
Siamack A. Shirazi ◽  
Brenton S. McLaury
Keyword(s):  
Multiphase Flow ◽  
Solid Particle ◽  
Flow Patterns ◽  
Particle Impact ◽  
Solid Particle Erosion ◽  
Particle Erosion ◽  
Erosion Rates ◽  
Severe Erosion ◽  
Fluid Properties ◽  
Sand Particles

Solid particle erosion is a major problem in many industrial applications where solids are entrained in gas and/or liquid flows. For example, erosion of production equipment, well tubing and fittings is a major operating problem that costs the petroleum industry millions of dollars each year. Entrained sand particles in the oil/gas production fluid impinge on the inner surfaces of the pipes, fittings, and valves that result in solid particle erosion. In certain production situations with corrosive fluids, erosion is compounded with corrosion causing severe erosion-corrosion. Even in situations when sand control means are utilized such as gravel packing and sand screens, small sand particles can plug sand screens promoting higher flow velocities through other portions of the screens causing failure and allowing sand production. Erosion can cause severe damage to the piping and equipment wall, resulting in loss of equipment and production downtime. Solid particle erosion is a mechanical process by which material is removed gradually from a solid surface due to repeated impingement of small solid particles on the metal surface. The erosion phenomenon is highly complicated due to the number of parameters affecting the erosion severity, such as production flow rate, sand rate, fluid properties, flow regime, sand properties, sand shape and size, wall material of equipment, and geometry of the equipment. For ductile materials, erosion is caused by localized deformation and cutting action from repeated particle impacts. It is well known that solid particle erosion rates are a strong function of the impacting velocity of particles and also the mass of impacting particles. Predicting solid particle erosion in multiphase flow is a complex task due to existence of different flow patterns. The existence of different flow patterns and sand and liquid holdup in vertical and horizontal pipes means that a unique erosion model has to be developed for each flow regime if the model is to account for the number and velocity of impacting particles. The particle impact velocity is affected by the pipe geometry, carrying fluid properties and velocity, flow pattern, particle size and distribution in the flow. Among different multiphase flow patterns in horizontal and vertical flows, severe erosion damage can occur in annular and slug flows with high gas velocities and low liquid velocities. Although there is a lack of accurate mechanistic models to predict solid particle erosion, there is a need to develop engineering prediction models for multiphase flows. Earlier erosion calculation procedures in multiphase flow were primarily based on empirical data and the accuracy of those “empirical” models was limited to the flow conditions of the experiments. A framework for developing a model has been established for predicting erosion rates of elbows in multiphase flow. The model considers the effects of particle velocities in gas and liquid phases upstream of the elbow. Local fluid velocities in multiphase flow are used to determine representative particle impact velocities. Also based on data representing sand holdup for several flow regimes, the masses of impacting particles are estimated. Erosion experiments are also conducted on elbows in two-inch and three-inch large scale multiphase flow loops with gas, liquid and sand flowing in vertical and horizontal test sections. Based on the experimental data for different flow regimes including slug, wet gas and annular flow a method for improving a previous model is discussed and is being implemented to predict erosion rates in multiphase flow.

The Effect of Solid Particle Erosion on the Mechanical Properties and Fatigue Life of Fiber-Reinforced Composites

2006 ◽  
Author(s):  
N. H. Yang ◽  
H. Nayeb-Hashemi
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Solid Particle ◽  
Impact Angle ◽  
Fatigue Properties ◽  
Particle Impact ◽  
Solid Particle Erosion ◽  
Particle Erosion ◽  
Erosion Damage ◽  
Impact Angles

The effect of solid particle erosion on the strength and fatigue properties of E-glass/epoxy composite was investigated. Solid particle erosion with SiC particles of 400 μm to 500 μm in diameter was simulated on 12 ply [45°/-45°/0°/45°/-45°/0°]s E-glass/epoxy composites with a constant particle velocity of 42.5 m/s and solid particle to air volume ratio of 6 kg/m3 at impact angles of 90°, 60°, and 30° for 30, 60, 90 and 120 seconds. Damaged and undamaged specimens were subjected to tensile tests while monitoring their acoustic emission (AE) activity. An erosion damage parameter was defined as a function of the particle impact angle and erosion duration to determine the residual tensile strength of the composite. Scanning electron microscope (SEM) images of the erosion damaged specimens revealed the same damage mechanism occurred at different impact angles. The AE stress delay parameter was used to predict the residual tensile strength of erosion damaged composites. Tension-tension fatigue tests were performed on virgin specimens and specimens exposed to erosion damage of 60 seconds and 90 seconds at 90° particle impact angle to observe the effects of erosion damage on the fatigue life. A modified Basquin's equation was defined to predict the fatigue life of the erosion damaged specimens.

Uncertainty Estimation in CFD Simulations of Erosion for Elbows

2021 ◽  
Author(s):  
Elham Fallah Shojaie ◽  
Thiana A. Sedrez ◽  
Farzin Darihaki ◽  
Siamack A. Shirazi
Keyword(s):  
Solid Particle ◽  
Turbulence Models ◽  
Uncertainty Estimation ◽  
Solid Particles ◽  
Solid Particle Erosion ◽  
Particle Erosion ◽  
Cfd Simulations ◽  
Erosion Prediction ◽  
Erosion Models ◽  
Near Wall

Abstract Computational Fluid Dynamics (CFD) is used extensively in the industry and academia for analyzing the motion of solid particles and the associated solid particle erosion that may occur in various pipe components. However, CFD simulations always carry levels of inherent uncertainties due to the numerical approximations of governing equations, generated grid, and turbulence models. Also, because of the complex nature of solid particle erosion, additional uncertainties are added to erosion prediction simulations. Aspects such as particle size, number of impacts, particles’ initial condition, near-wall mesh effects, forces considered in particle tracking procedures, particle-particle interaction, and near-wall particle-fluid interactions are all possible sources of uncertainties associated with erosion prediction in CFD. Furthermore, unique problems that accompany discrete phase handling and erosion calculation needed for the industrial applications magnify the importance of uncertainty estimation in erosion calculations. Commercially available CFD codes are used with user-developed subroutines to investigate particle erosion prediction uncertainties, numerically in elbows, by considering gas and liquid flow for several pipe sizes. Moreover, different particle sizes, inlet flow velocities, turbulence models, wall functions, and erosion models are examined. According to the ASME’s Verification and Validation (V&V) standard, uncertainties are divided into 3 categories; input, numeric, and modeling. Thus, it is possible to utilize the ASME’s standard as guidance to predict uncertainty for erosion simulations. Furthermore, an extra parameter was considered for uncertainties to account for the uncertainties induced by different simulation procedures and erosion models. The current investigations resulted in developing a framework for estimating uncertainties of erosion simulation. For each simulation result, two bounds (upper and lower) were predicted for erosion. The results show that the Reynolds Stress turbulence model (RSM) and Arabnejad’s erosion model usually predict results corresponding to the lowest uncertainties.

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