Elbow Erosion Research Articles

A study of asymmetric guided wave propagation mechanism in elbow and prediction of elbow erosion degree based on SAFE and GA-LSSVM methods

Aiming at the problems of complex sensor layout, low detection accuracy when using guided wave to detect the elbow’s erosion degree, this research presents a new approach based on asymmetric guided wave and Genetic Algorithm-Least Support Vector Machine (GA-LSSVM). The program for calculating elbow’s dispersion curve was compiled using the semi-analytical finite element (SAFE) method. Through numerical simulation, it is found that the bending mode in the guided wave signal at the outer arch back position of the receiving end decreases with the increase of the erosion degree, which leads to the decrease of the signal’s time domain energy. Finally, The GA-LSSVM model were used to predict various elbow specimens’ residual wall thickness, and the results shows the high prediction accuracy. The average accuracy of predicting the new elbows is 87.63%. This research provides a feasible scheme for detecting elbow’s erosion degrees in engineering.

Simulation of Elbow Erosion of Gas–Liquid–Solid Three-Phase Shale Gas Gathering Pipeline Based on CFD-DEM

Shale gas gathering pipelines often contain liquid water and solid sand in the early stage of production, which leads to the failure of pipeline components easily under the action of gas–liquid–solid three phases. A computational fluid dynamics (CFD) model based on the fluid volume method (VOF) and discrete element method (DEM) was established to study the flow law of gas–liquid–solid three-phase flow in the elbow of shale gas gathering pipeline and the erosion law of the inner surface of the elbow was studied by coupling the Oka erosion prediction model. By comparing the experimental results of erosion damage of the elbow, it is found that the model established can well predict the erosion characteristics and erosion amount under the action of three phases. Combined with the field pipeline parameters and operating conditions, the paper further simulates the elbow erosion behavior under relevant working conditions. The results show that the particles rotate clockwise from the outer wall of the pipe through the bottom of the pipe when passing through the elbow under the action of gas and water phases. When the gas velocity increases, the particles at the elbow mainly gather at the bottom of the elbow and the wall of the outer arch. When the water content increases gradually, the particles gathered on the outer arch wall of the elbow move along the outer arch wall of the elbow and face the inner arch surface gradually, and the erosion area is mainly concentrated on the outer arch wall of the elbow and the outlet horizontal pipe. Under the condition of the liquid phase, the movement characteristics of the water phase and particles in the elbow of the gas gathering pipeline and the erosion characteristics of the pipeline surface are obviously different from those under the condition of the gas–solid two-phase. The model and simulation results established in this paper provide a reference for the erosion damage protection of shale gas gathering pipeline elbow.

Erosion Analysis and Optimal Design of Sand Resistant Pipe Fittings

Erosion of solid particles in a pipe elbow containing a 90° angle is investigated by simulation methods. In the process of shale gas exploitation, the impact of solid particles carried by fluid on the inner surface wall of pipes, as well as the turbulent flow, cause the erosion of pipes, which brings about heavy economic losses for the oil and gas industry. In the impact erosion of the inner surface wall of the pipe, the worst erosion occurs at the elbow. In this study, the erosion of a pipe elbow which has been widely used in actual production is analyzed, and the influence of the fluid velocity, the solid particle size, and the wall roughness on the erosion is investigated. Additionally, the simulation results of the erosion with the rebound and freeze boundary conditions are compared, indicating that setting the freeze boundary condition could significantly improve the computational efficiency by 74% with the acceptable accuracy. In order to reduce the impact erosion in the pipe elbow containing a 90° angle, an optimal design is proposed that can reduce the maximum erosion rate by 52.4%. These results complement the research of elbow erosion and provide ideas for the optimization problem of a pipe elbow containing a 90° angle.

The erosion rate prediction for the elbow in shale gas gathering and transportation system: RSM and GA-BP-ANN modeling

Elbow erosion caused by sand mixed in shale gas is a significant issue faced by shale gas gathering and transportation systems, posing a serious threat to the safe and stable production of shale gas. In this paper, the factors affecting elbow erosion in the shale gas gathering and transportation system are identified. The computational fluid dynamics (CFD) two-way coupling Euler-Lagrange method is used to investigate the single-action of various parameters on particle trajectory, erosion morphology, and maximum erosion rate, including pipe inner diameter, pipe R/D ratio, pipe bending angle, pipe bending orientation, solid particle velocity, solid particle size, and solid particle mass flow rate. Subsequently, the response surface methodology (RSM) is employed to quantitatively explore the synergistic interactions between these factors that affect the maximum erosion rate of the elbow, and a surrogate model for simple and rapid evaluation of the maximum erosion rate for elbows at the engineering level is proposed. Finally, the backpropagation artificial neural network (BP-ANN) optimized by genetic algorithm (GA) is used to train the samples obtained by Latin hypercube sampling (LHS) in the multi-factor range. By comparison, the RSM surrogate model and the GA-BP-ANN model reveal a favorable level of agreement with the experimental data, while considering various influential factors. It is important to note that each method possesses distinct advantages, limitations, and specific application environments. This research can provide quantitative references for preventing and controlling erosion within the shale gas gathering and transportation system.

Numerical simulation of water-slag elbow erosion-inhibiting by regulating the slag injection position with a novel preceding rotating sheet structure

The elbow erosion seriously jeopardizes the safe and stable operation of water–slag discharge pipeline of the coal gasification system. This work simulated water–slag elbow characteristics with various slag injection positions by simulating five simplified and representative erosion categories, including A-type horizontal-vertical elbow with an upstream flow, B-type horizontal-vertical elbow with a downstream flow, C-type vertical-horizontal elbow with an upstream flow, D-type vertical-horizontal elbow with a downstream flow and E-type horizontal-horizontal elbow. Compared with the C/D-type elbow, where particles were injected uniformly, the A-type elbow and E-type elbow were found to increase erosion rate, while the B-type elbow decreases erosion rate. An interesting discovery is that the elbow erosion rate is relatively low for small particles when particles are injected from the middle and bottom positions of the inlet section of the elbow. Based on the observation, a novel preceding rotating sheet structure was developed to regulate the particle injection position. It shows an excellent anti-erosion performance by reducing the maximum erosion rate of particles with diameters of 50, 100, and 200 μm by 23%, 35%, and 43%, respectively.

A novel AI-driven model for erosion prediction for elbow in gas-solid two-phase flows

Erosion is inevitable in pipeline gathering and transportation systems. Predicting erosion in typical pipe fittings is pivotal to ensure the safety and efficiency of the equipment. This work develops a novel predictive model for erosion in elbows under gas-solid flow conditions. The proposed model employs the Deep Belief Network (DBN) for feature extraction from the input parameters. Meanwhile, Kernel Extreme Learning Machine (KELM) is implemented to deeply analyze correlation between the eigenvalues and the erosion rate, thus improving the model's generalization performance. Furthermore, the Improved Coati Optimization Algorithm (ICOA) is utilized to optimize the model's hyperparameters, contributing to increased accuracy. To validate the reliability of the ICOA - DBN - KELM model, it was applied to both the experimental and simulated datasets. The outcomes demonstrate that the proposed model attains the highest prediction precision in both datasets compared to other models. Additionally, the model was assessed for reasonableness concerning trend consistency and dimensionless numbers.

An improved method combined modified drag model and modified erosion model based on LES for solid-liquid multiphase flow and erosion with application in a 90° elbow

In various industrial processes, solid-liquid multiphase flows involving continuous carrier and discrete particle phases have erosion challenges. In this work, a modified drag model that considers the influence of turbulence intensity and a modified erosion model that considers the effect of low-angle impact are developed. An improved method combined modified drag model and modified erosion model based on LES is proposed for numerical simulation of solid-liquid multiphase flow and erosion. The commercial software ICEM for grid generation and ANSYS FLUENT for LES are used in the present work. In validation test of velocity distribution of solid-liquid multiphase flow in a vertical pipe, the mean relative error of the liquid phase pulsation velocity is 10.01 % for modified drag model, whereas the mean relative error is 16.11 % for original drag model. In validation test of the maximum erosion depth from a submerged impact test at a tilt angle of 45°, the relative error is 0.23 % for modified erosion model, while the relative error is 13.39 % for original erosion model. Then, the improved method is employed to compute the characteristics of solid-liquid flow and erosion in a 90° elbow. Particles have a significant influence on liquid flow in the shear layer area where the inner arch separation zone interacts with the main flow, and this influence is most pronounced at the position of r* = 0.3 at yd = 0.4D. At this position, particles result in 15.27 % reduction in liquid velocity and 8.75 % increase in turbulence intensity. The mean relative error of the elbow erosion rate by using the improved method is 16.95 %, whereas it is 31.34 % of the reference work. The erosion is affected by impact velocity, angle, and particle number, and the most significant parameter is the particle number in the severe erosion area.

Experimental and Numerical Simulation Analyses of Elbow Erosion in Surface Process of Deepwater Gas Well Testing

Experimental and Numerical Simulation Analyses of Elbow Erosion in Surface Process of Deepwater Gas Well Testing

Study on the Erosion Characteristics of Non-spherical Particles in Liquid-solid Two-phase Flow

Elbow erosion, defined as wall thinning due to the continuous interactions between solid particles and surface, is a common phenomenon in catalyst addition/withdrawal pipeline systems used in residual oil hydrogenation units. This form of erosion can seriously affect the reliable pipeline operation. The present paper describes the construction of realistic cylindrical catalyst particles using the multi-sphere clump method and computational fluid dynamics/discrete element model simulations to study the erosion of pipe walls under different inlet velocities and particle aspect ratios. An optical shooting experiment is carried out to ensure the accuracy of the calculation method, and the model performance is compared using several existing drag models. The results show that the drag model of Haider & Levenspiel is more accurate than the others in revealing the actual cylindrical particle flow. A higher inlet velocity is observed to increase the kinetic energy of the particles and affect their spatial distribution. Specifically, when the Stokes number is greater than 113.7, the position of the maximum erosion rate shifts from the elbow’s outer wall to the inner wall. Cumulative contact energy is introduced to quantify two different types of particle-wall contacts. With a growing particle aspect ratio, the proportion of tangential energy gradually increases, which indicates that sliding is the main contact mode. The results presented in this paper provide a reference for engineering erosion calculations.

A New Method for Erosion Prediction of 90° Elbow Based on Non-Axisymmetric Ultrasonic-Guided Wave and the PSO-LSSVM Algorithm.

The non-axisymmetric exciting guided wave can detect the thinning section of the elbow, and the time domain energy value of the signal collected at the outer arch position of the receiving end displays a downward trend as the remaining thickness of the erosion area decreases. To address the difficulty in detecting the erosion degree of the elbow with high accuracy, this paper uses the linear frequency modulation (LFM) signal to excite a non-axisymmetric guided wave that propagates in the 90° elbow and collects signals through four PZT receivers. To predict the erosion degree, the corresponding relationship between the energy value of the four signals after fractional Fourier filtering and the degree of elbow erosion is established through the particle swarm optimization (PSO)-least squares support vector machine (LSSVM) algorithm. The results show that the method proposed has an average accuracy rate of 98.1864%, 94.7167%, 99.119%, and 99.9593% for predicting the erosion degree of four elbow samples, and 94.0039%. and 81.2976% for two new erosion degrees, which are higher than the nonlinear regression model, LSSVM algorithm, and BP neural network algorithm. This study has guiding significance for real-time monitoring of elbow erosion.

Detection of the pipeline elbow erosion by percussion and deep learning

Elbows are commonly used in pipelines to change the direction of flow, and the pipeline elbows are prone to erosion caused by the transported medium. Detection of the pipeline elbow erosion is critical to the health of the pipeline system. Currently, most of the detection methods of the pipeline elbow erosion level require the installation of the constant-contact sensor, which are constrained under certain environments. This paper proposes a novel detection method for the pipeline elbow erosion, which is easy-to-implement, low-cost, and free of the installation of a constant-contact-sensor. The proposed method combines percussion, variational mode decomposition (VMD), and deep learning. The percussion-induced audio signal (single-hit) is decomposed into seven modes using VMD, and the multiple random convolutional kernel transform (Multi-Rocket), a machine learning method, is used to select the most representative mode for the single-hit audio signal. Finally, the capsule neural networks, a deep learning method, is utilized to classify the most representative mode under six levels of erosion severity (six classes). To verify the effectiveness of the proposed method, two case studies are conducted under three pipeline elbows with similar structure and dimension. In case study I, all the methods achieve similar classification accuracy (around 100%) under six erosion levels. In case study II, the proposed method (>90%) is far more effective than other shallow learning and deep learning methods (all < 80%) in terms of the classification accuracy. The results demonstrate the superiority of the proposed method in the detection of pipeline elbow erosion levels. To the best of our knowledge, this paper is the first attempt to study the detection of pipeline elbow erosion levels by combining the percussion method and deep learning.

An algorithm combining sedimentation experiments for pipe erosion investigation

Hydraulic fracturing is an essential technology for continuously developing non-renewable energy, such as oil and gas. The erosion of solid-liquid two-phase flow in hydraulic fracturing is a theoretical problem that needs to be solved urgently. In the current computational fluid dynamics-discrete element method (CFD-DEM) research, we present calculation methods for the collision restitution coefficients of quartz particle in Newtonian fluids (1 mPa s) and non-Newtonian fluids (10 mPa s and 20 mPa s). The influence of power-law fluid is considered in the algorithm, and the problem of particle penetration in the CFD-DEM method is optimized. These experimentally obtained collision restitution coefficients are incorporated into the optimized CFD-DEM method to consider the influence of fluid viscous forces on particle collisions. The accuracy of the numerical simulation method in this paper is verified by particle settlement and erosion experiments. The elbow erosion experiment is then used to validate the correctness of the erosion simulation. Finally, the erosion behavior of the fracturing pipe (elbow and tee junction) under different conditions is analyzed.

CFD–DEM investigation of gas-solid flow and wall erosion of vortex elbows conveying coarse particles

Vortex elbows are generally used to mitigate erosive wear while conveying fine particles. This paper presents a modified vortex elbow designed to handle coarse particles. Gas–solid flows and wall erosion of the modified vortex elbow are studied by the combined approach of discrete element model for particles and computational fluid dynamics for the gas phase. The validity of the model is first examined by comparing the predicted pressure drop and wall erosion with experimental measurements for a standard elbow. Then, via the model, the effects of particle size on the flow characteristics and elbow erosion of the modified vortex elbow are quantified and compared with those of the standard elbow. The results show that the vortex elbow decreases the maximum penetration ratio and total penetration depth for all the particle sizes considered. These effects become more significant for larger particles. The wall erosion is also elucidated using flow characteristics.

Experimental and numerical assessments on solid particle erosion in upward vertical-horizontal and horizontal-vertical downward elbows for multiphase and gas-sand flows

Solid particle erosion is unavoidable in the pipeline fitting components in different engineering applications, such as in the oil and gas industry. Elbows have been used as an efficient fitting component to change the flow direction in pipeline systems. They are commonly fitted in series. Thus, it is valuable to examine the effect of distance between two elbows in series on solid particle erosion of elbows. In the presented work, flow visualizations, paint removal tests, and erosion measurements were conducted on two test configurations of standard 50.8 mm elbows in vertical-horizontal flow. The distance between the two elbows to the pipe diameter ratio (L/D) are 1 and 5 to investigate the distance effect on erosion on the elbows. The multiphase flow regime is churn/annular flow with superficial gas and liquid velocity of 16 m/s and 0.5 m/s, respectively, and 300 μm sand size. The results of the flow visualizations showed a thin liquid film covering the inside wall of the elbows. Liquid patches or portions were flowing and covering the outer wall of the first and second elbows for the L/D = 1 test configuration. The paint removal experiment results showed that the paint started to remove at around 45° in the first elbow and about 60° in the second elbow of both test configurations with the 1D and 5D distance between the two elbows. The erosion measurement results showed a good agreement concerning the location of the maximum erosion compared to the paint removal tests. In addition, the erosion measurement results showed that the maximum erosion magnitude in the first elbow with the L/D = 1 and L/D = 5 test configurations is higher than the second elbow by a factor of 1.35 and 3.14, respectively. In addition, Computational Fluid Dynamics (CFD) approach was used to study the effect of distance between two standard 76.2 mm elbows in series with 31 m/s gas velocity and 300 and 75 μm sand sizes. The CFD results showed agreements with the available experimental data. The CFD results showed that the maximum erosion ratio in the second elbow is lower than the first elbow in the gas-solid flow condition.

Effect of pipe size on erosion measurements and predictions in liquid-dominated multiphase flows for the elbows

Solid particle erosion in pipelines and pipe fittings occurs when solids are produced in the oil and gas industries during transporting fluids. Erosion of elbows in series for liquid-dominated flows has gained recognition as many oil fields operate in deep-water subsea flow lines and also in conventional wells onshore. Although significant data is available for gas-dominated flows, the data for liquid-dominated flows are scarce and limited to 50.8 mm pipe elbows in dispersed bubble flow only. Thus, it is essential to determine erosion for different pipe sizes to investigate the pipe size effect and for different flow regimes. This work conducts experiments in vertical liquid-solid flows, and liquid-gas-solid churn flows to examine erosion using 340 μm sand particles in 50.8 mm and 76.2 mm standard SS316 elbows in series separated at a distance of three diameters between them. In addition, flow visualization and paint-removal experiments are conducted to predict the erosion patterns in the elbows. Furthermore, Computational Fluid Dynamics (CFD) simulations are performed to simulate the experimental conditions. Eulerian and VOF multiphase models with different turbulence models are used in CFD simulations to predict erosion on the elbows in series and compare with the experimental results. The CFD results, when modified to account for the lubrication effects of the liquid, can predict the experimentally observed erosion pattern and the magnitudes.

Modeling of sand transport and elbow erosion in horizontal two-phase slug flow

Horizontal wells play an important role in maximizing the recovery of hydrocarbons from oil and gas reservoirs. During production, if the rate of production of produced fluids with sand particles is low, the deposition of sand particles in horizontal flow lines can wreak havoc on production systems in such a way as to cause increased pressure loss and reduction or loss of production when the pipe is partially or completely blocked. On the other hand, if the production rate of fluids is high, the impact of sand particles on the wall of the pipe will erode the inner surface of the pipe fittings. In this case, erosion can be severe enough to cause a hazardous spill and complete shutdown of systems. Therefore, it is important to quantify the sand transport and erosivity of different flow regimes. Under moderate velocities, there exists a flow regime which is called slug flow which is characterized by the intermittent appearance of liquid slugs propagating through the pipe. Studying the sand deposition and erosion due to sand particles entrained in intermittent flows is extremely difficult since the solid particle velocity magnitudes are coupled with several multiphase flow parameters such as phase distribution and slippage between the phases. This work focuses on the improvement of mechanistic models for predicting critical deposition of sand particles in horizontal pipes and erosion in horizontal-horizontal elbows. In this investigation, a modified model is proposed to better predict the critical deposition velocity and the characteristic particle velocity as a function of the slug flow characteristics. The model predictions are compared with the sand transport and erosion data collected at the University of Tulsa and other research institutions. The results show that the new approach provides improved predictions for sand transport and maximum erosion in standard elbows when compared with existing models.

Study Investigates Multiphase Flow in Circular and Triangular Pipes

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 208101, “Multiphase Flow in Circular and Triangular Pipes: Examining Flow Characteristics, Sand Erosion, and Heat Transfer Through Computational Fluid Dynamics and Experimental Work,” by Ronald E. Vieira, Thiana A. Sedrez, and Siamack A. Shirazi, SPE, The University of Tulsa, et al. The paper has not been peer reviewed. _ The authors present a survey of air/water and air/water/sand flow through circular and triangular pipes. The main objective of this investigation is to study the potential effects of triangular pipe geometry on flow patterns, slug frequency, sand erosion in elbows, and heat transfer in multiphase flow. Introduction The complete paper summarizes several important benefits of triangular pipes as compared with circular pipes in multiphase flow. First, a survey of horizontal multiphase air/water flow through circular and triangular pipes is presented. Second, the erosion patterns in triangular elbow geometry are examined experimentally and predicted computationally using existing erosion models. The results are compared with circular elbows for steel materials. Initially, an experimental investigation was performed using flow visualization with a paint-removal study to determine the location where particles impinge and lead to erosion. Erosion-measurement experiments are also conducted in a flow loop containing liquid and 300-µm sand particles. The experimental studies were followed by computational fluid dynamics (CFD) erosion modeling for liquid/sand and liquid/gas/sand flows in circular and triangular elbows. Third, an attempt is made to analyze the effect of circular and triangular pipe configurations on heat transfer at constant wall temperature and under the influence of different Reynolds number values. The analysis was performed numerically using CFD for turbulent and laminar flow with water at two different viscosities. Experimental Setups The main objective of the first set of experiments was to study the potential effects of triangular pipe geometry on flow patterns and slug frequency in gas/liquid flows. The experimental facility and methodology are detailed in the complete paper. The setup consisted mainly of a pump, tank, separator, and test-loop section (pipes). The water flow rate (containing particles) was measured by timing the liquid volume loss from the tank. Measurements were repeated three times, and the averaged measured time was used. The gas-flow rate was measured using a digital vortex flowmeter. Experiments were performed horizontally and near atmospheric pressure conditions. The circular test section consisted of a 2-in.-inner diameter, 28-ft-long clear acrylic pipe. The triangular test section was formed from three 7-ft-long, 2.7-in.-wide sheets of cast acrylic. The effect of corners of the triangular pipe on the liquid distribution compared with round tubes was investigated using two different orientations of triangular pipe, apex upward and downward. Detailed videos and slug-frequency measurements were collected for horizontal air/water flow through the round and the triangular clear pipes to identify flow patterns. The slug frequency was measured by analyzing the videos.

Solid particle erosion prediction in elbows based on machine learning and swarm intelligence algorithm

Continuous impact of solid particles causes severe pipeline wear, and may result in leakage in directional change areas such as elbows. Accurate prediction of erosion is essential in the petroleum industry. In this study, a new machine learning (ML)-based model for predicting elbow erosion was established. Seven parameters were selected as feature inputs from the fluid characteristics, particle characteristics, and pipe characteristics. The maximum erosion rate was used as the predicted output. Based on the gas–solid flow data, the prediction accuracy of different ML models was compared. The kernel extreme learning machine (KELM) model was considered as the optimal model. For gas–liquid–solid flow, incorporating swarm intelligence (SI) algorithms, the whale optimization algorithm–hybrid kernel extreme learning machine (WOA–HKELM) erosion prediction model was proposed; the predictions were compared with the experimental values. The root mean square error (RMSE) of the prediction was 0.82 × 10−3, which is consistent with the experimental results. It was also demonstrated that the model can capture the trend of the influence of mixed dimensionless inputs on the prediction results in churn and annular flow.

Numerical prediction of solid particle erosion in angle-cutting elbows with gas–solid flow

Angle-cutting elbows (ACEs) are important components of pipelines for fluid diversion and distribution. Severe erosion may occur on the internal walls of ACEs used to transport solid–gas/liquid flow. Erosion may cause pipeline failures. Therefore, the ACE erosion is a fundamental problem. However, the literature on the erosion characteristics and structural optimization of ACEs is rarely reported. This study conducts a numerical prediction of solid particle erosion in ACEs with gas–solid flow. Simulation models based on the two-way coupled Eulerian–Lagrangian approach and the E/CRC model are combined with particle-wall rebound models and a user defined function in the dispersed phase model. Simulation results are verified through a comparison with previously reported experimental results. The findings show that serious erosion occurs in the downstream part of the concave wall of ACE, whereas only slight erosion occurs on the convex wall of ACE. Therefore, anti-erosion measures should be adopted for the concave wall of ACEs. In addition, structural optimization of ACEs for erosion reduction is conducted. The optimal cutting angle is 40° &gt; 50°, and the optimal non-dimensional cutting length is &lt;1.05. The influence of fluid parameters on erosion characteristics is also determined. The erosion rate on the concave wall increases linearly with particle diameter and exponentially with inlet velocity.

Numerical Simulation of Viscosity Effects on Carbon Steel 90° Elbow Erosion due to Sand-Liquid Flow

Elbow pipes are important pipeline components in hydrocarbon transportation systems, and they were prone to erosive wear by the impact of abrasive particles. A discrete phase modeling (DPM) and numerical simulation of the liquid-sand transportation process was carried out focused on the investigation into the influence of carrier fluid viscosity on erosion distribution of carbon steel 90° elbows. The accuracy of the predicted results was validated by comparison with experimental data. CFD simulations have been carried out by combining DPM to predict the erosion rate and particle impaction regions in carbon steel 90° elbow with a diameter of 50.8 mm. The fluid viscosity is set for 1cP, 5cP, and 15 cP with an inlet velocity of 8 m/s, and the size of sand particles is 200 μm. While the maximum erosion rates enhance with an increase in fluid viscosity, the location of maximum particle impaction has been specified to be adjacent to the outlet for 1 cP and 5 cP carrier fluid viscosity. It is also found that increasing the viscosity does not considerably alter the average erosion rate. Moreover, the increase in carrier fluid viscosity with the same flow velocity influences maximum erosion rate and yields 1.45 times higher erosion rates at 15 cP compared to 5cP and 1cP. This is mainly due to severe sand impaction at the side of the elbow wall.