Erosion Experiments Research Articles

Effect of solution aging treatment on corrosion resistance and erosion resistance of laser metal deposition 17-4PHss

Slurry erosion and cavitation erosion are the primary causes of failure in pass flow components, and preventive maintenance can effectively extend their service life. In this paper, 17-4PH stainless steel was prepared using laser metal deposition (LMD) technology and aged to investigate the effect of solution treatment on its microstructural transformations. The microhardness, electrochemical corrosion behavior, slurry erosion resistance, and cavitation erosion behavior of the as-built and solution-treated, aged samples were analyzed, with traditional forged specimens used as controls. During heat treatment, the microstructure fully transformed to martensite, and NbC precipitated as a second phase. Solution treatment led to microstructural coarsening, while aging significantly refined the microstructure and produced partial reverted austenite. Microhardness analysis showed that the microhardness of the solution-treated and aged samples increased to 465.5 ± 8.6 HV0.2 due to the combined effects of finer and more uniformly distributed NbC precipitation and grain refinement. The solution aging samples exhibited the lowest corrosion current density and the highest corrosion potential, influenced by the presence of reverted austenite. Slurry erosion results indicated that the corrosive environment accelerated mass loss due to the synergistic effects of mechanical abrasion from gravel and brine corrosion. Meanwhile, the solution aging samples demonstrated superior resistance to slurry erosion, with mass losses in clear water and brine slurry of only 69 % and 63 % of those observed in the traditional forged samples. In the cavitation erosion experiment, the solution aging sample showed the lowest cumulative mass loss (3.54 ± 0.18 mg), and the work-hardening of the reverted austenite further enhanced the cavitation erosion resistance of the solution aging sample.

Effects of jet impact angle on cavitation erosion intensity and cavitation cloud dynamics

Cavitation water jet technology has been widely used in industrial production, but the effects of cavitation cloud evolution and erosion patterns at different impact angles remain to be determined. To study the erosive effects of cavitation jets at different impact angles, this study conducted erosion experiments with different impact angles. The flow conditions are varied at 45°, 60°, 75°, and 90°, four different jet impact angles on the target surface at the optimal standoff distance. The influence of impact angle on the erosion effect was explored by erosion morphology and erosion quality. Larger mass loss occur under erosion conditions at larger impact angles (75° and 90°), while relatively less mass loss occurs at smaller impact angles (45° and 60°). Furthermore, the evolution of cavitation clouds at different impact angles is illustrated through high-speed visualization experiments. The changing of cavitation jet structures is investigated by Proper Order Decomposition(POD) analysis. The smaller the impact angle, the closer the position of the re-entrant jet is to the nozzle, which leads to an increase in the frequency of cavitation cloud shedding. Meanwhile, cavitation bubbles don't have enough time to develop, resulting in reduced erosion capacity. The behaviour of the cavitation jet impinging on the target at different impact angles is simulated by the Large Eddy Simulation (LES) turbulence model. As the angle decreases, the pressure fluctuation caused by the cavitation cloud on the target surface decreases, and the duration also decreases accordingly. The results of this study provide technical support for the application of cavitation jets under different impact angle conditions and also help to understand the cavitation erosion mechanism under different impact angles.

Experimental study and analysis of the static and dynamic mechanical properties of graphene oxide cement soil under composite salinity erosion

In coastal and saline-alkali regions, cement soil materials face significant challenges from salt erosion and both dynamic and static loads, threatening their structural stability. To enhance the mechanical properties of cement soil, this study explores the incorporation of graphene oxide (GO). We subjected GO cement soil specimens to various concentrations of a composite salt solution (with a NaCl to Na2SO4 mass ratio of 1:1) in erosion experiments lasting 7 and 30 days. The specimens were analyzed through unconfined compressive strength tests, split Hopkinson pressure bar (SHPB) tests, and scanning electron microscopy (SEM) to examine changes in stress-strain curves, peak stress, and energy dissipation. The results indicate that the dynamic and static peak stresses, energy absorption, and energy absorption efficiency of the GO cement soil specimens are inversely related to the concentration of the mixed salt solution. Notably, in a 4.5 g/L erosion environment after 7 days, an increasing trend was observed in static peak stress, energy absorption, and energy absorption efficiency. Additionally, when the salt concentration was fixed, these properties showed a positive correlation with impact gas pressure. SEM analysis revealed that the nucleation effect of GO and its strong bonding with the cement matrix significantly improved the microstructure of the specimens by reducing pores and defects, thus enhancing density and overall performance. Furthermore, in an 18 g/L erosion environment, a notable presence of ettringite (AFt) was identified in the GO cement soil specimens.

An investigation on the mechanical, thermal and tribological properties of newly developed polyester composites made with Pistachio shell particles for industrial applications

The drive for sustainability and addressing environmental concerns has led to the productive use of bio-waste. This research investigates the potential of pistachio (Pistacia vera) nut shell particles as a novel filler in polyester composites. The study explores the use of these nut shells as a reinforcing material in polyester-based composites to evaluate their mechanical and thermal properties. Pistachio shell particles (PSP) are mixed with polyester resin in varying weight fractions (0%, 1%, 3%, and 5%) to create a new type of composite. The impact of filler content, impingement angle and striking velocity on the erosive wear behavior of these composites are also studied. The mechanical results for the composites revealed that incorporating PSP filler resulted in the maximum rise in tensile (96.61%), impact strength (66.66%), micro-hardness (52.94%), under loading of 5 wt% of PSP filler. However, the composite with 3 wt% of PSP filler, resulted in the maximum rise of flexural strength (135.65%) and flexural modulus (45.28%). Results showed that, composites with 5 wt% of PSP filler exhibited superior erosive resistance. An optimal parameter setting is determined for minimum erosion rate and subsequently validated by conducting confirmation experiment as per Taguchi methodology. Different modes of material removal, wear craters and other qualitative attributes are examined by a scanning electron microscopy during erosion experiment of the samples. Thus, the utilization of agro/food wastes in the development of bio-based products holds significant potential and offers the possibility of replacing conventional materials in various industrial applications.

Influence of Pseudomonas aeruginosa-based biopolymer on mitigating soil erosion and heavy metal dispersion

Extreme weather phenomena caused by climate change have exacerbated soil erosion and the subsequent dispersion of pollutants. Pseudomonas aeruginosa is known to contribute to the remediation of polluted water and reduce the geochemical mobility of heavy metals in contaminated soil. However, studies on the influence of biopolymers produced by soil microbes and P. aeruginosa on physical soil properties and soil erosion are limited. We aimed to investigate the influence of soil microbes on the mitigation of soil erosion and geochemical dispersion of heavy metals using a naturally occurring microbial substance, P. aeruginosa-based biopolymer (PBB). The PBB comprised carboxyl, hydroxyl, and amine surface functional groups; consequently, the biopolymer effectively sequestered Cd (maximum sorption capacity qm = 45.7 mg/g), Cu (qm = 26.7 mg/g), Pb (qm = 64.9 mg/g), and Zn (qm = 26.1 mg/g) in the solution. The PBB amendment of the soil improved the physical properties associated with soil erosion, increasing soil aggregation stability and shear strength by 41.6% and 36.8%, respectively. The extraction of heavy metals from soil via synthetic precipitate leaching decreased by 54.2% following the PBB amendment, and a negative correlation was observed between soil aggregate stability and heavy metal extraction, indicating that this microbial substance could immobilize pollutants by adsorbing cationic metal ions and inhibiting water-induced disaggregation. In the soil erosion experiments, soil loss and heavy metal extraction decreased by 70.9% and 43.8%, respectively, following the PBB amendment. These aggregation and sorption effects of the PBB underscore the potential of soil microbes to mitigate soil erosion and immobilize the geochemical dispersion of heavy metals, thereby contributing to the conservation of soil and water quality in areas surrounding contaminated slopes and heavy metal-contaminated areas, such as cut slopes, agricultural fields, mine dumps, and dams.

Dynamic interaction between refractory and low‐carbon low‐silicon Al‐killed steel

AbstractTo investigate the dynamic interaction between refining refractory and low‐carbon low‐silicon Al‐killed steel, the “refractory‐molten steel‐inclusion” system was analyzed using dynamic erosion experiments and the FactSage database. This study discussed the formation of interfacial layers between various refining refractories and molten steel, as well as the transformation of nonmetallic inclusions in steel. The findings indicate that the interaction between refractories and molten steel produces a distinct interface layer. The influence of various refining refractories on inclusions varies significantly. MgO‐C refractory promotes the formation of MgO·Al2O3 inclusions in steel, while Al2O3‐MgO refractory leads to the formation of SiO2‐MnO‐Al2O3 inclusions. Both Al2O3‐SiC refractory and Al2O3‐MgO‐C refractory result in Al2O3 inclusions with trace levels of MgO. Steel refined with Al2O3‐MgO‐C refractory has increased MgO content within Al2O3 inclusions but still does not reach the stoichiometric ratio of MgO·Al2O3. As the initial Al content increases, the influence of MgO‐C refractory inclusions becomes increasingly noticeable. The average MgO content within the inclusions rises with the reaction duration, achieving as high as 62.9%. The transition path of Al2O3 inclusions in molten steel follows “Al2O3→MgO·Al2O3→MgO.”

Preparation of protective coatings for the leading edge of wind turbine blades and investigation of their water droplet erosion behavior

The damage caused by rain droplet erosion to the leading edge of wind turbine blades is extremely severe. To reduce this issue, in this study, hydroxyl-terminated polybutadiene (HTPB) and isophorone diisocyanate (IPDI) were used as the polyurethane (PU) polyol and curing agent, respectively, to prepare a PU coating with a high resistance to water droplet erosion (WDE) for the protection of the leading edge of wind turbine blades. The effect of n (–NCO):n (–OH) (R-value, n is the molar ratio) on the mechanical properties and WDE resistance of PU coatings, the relationship between the two performances, and the influence of the erosion conditions on the WDE behavior were investigated for the first time. The results show the existence of a correlation between the mechanical properties (hardness, impact, flexibility, and tensile strength) and WDE resistance of the coating. While, a better abrasion resistance is found not to result in a better WDE resistance. The PU coating with an R-value of 1.2 shows an optimal WDE resistance in both atomization and jet erosion experiments. In atomized droplet erosion (ADE) experiments, the change in erosion velocity accelerates the incubation period of coating erosion damage and increases the erosion rate. In jet droplet erosion (JDE) experiments, the damage to the coating is closely related to the erosion angle, reaching a maximum at an impact angle of 60°. Furthermore, in the ADE experiments, various erosion morphologies, such as pits, grooves, cracks, and stepped texture, are observed on the damaged coating surface. While, regarding the JDE experiments, holes, grooves, and cracks are observed. Such damage is caused by the combined effects of water hammer pressure, lateral jets, and local permeation.

CAVITATION EROSION IN FRANCIS TURBINES

The phenomenon of secondary flow is a global problem that causes cavitation erosion in hydraulic equipment. Cavitation is a phenomenon of localised corrosion of the metal surface leading to instability and highly uneven flow behaviour with a consequent excessive noise, vibration, and decreased efficiency in Francis, Kaplan, and other turbines. Both Kaplan and Francis turbines are reaction turbines. Francis turbines (FT) are used worldwide due to their relatively compact design, high efficiency, and operation underwater at heights ranging from 100 to 300 m with an efficiency ranging from 90% to 95%. The article analyses the latest relevant research conducted by various researchers on different turbine components. The analysis shows that this type of erosion depends on flow characteristics, surface, and properties of the material eroding. Tools for design optimisation, cavitation erosion, and well-conducted experiments will provide results for identifying and reducing erosion. Although some researchers conducted experimental work to study the effect of cavitation erosion, literature on computational fluid dynamics (CFD) is very scarce. Over the past two decades, experts have been applying CFD methods to detect cavitation by examining areas where the pressure is below the vapour pressure with a single-phase model. Most studies do not consider the impact of cavitation bubbles on the flow field. However, these methods cannot provide detailed information, such as the impact of cavitation on efficiency or a more accurate prediction of the cavitation bubble size. Some researchers use cavitation inducers and some of the latest visualisation methods as experimental tools to study cavitation phenomena. In the last decade, a numerical methodology has been widely used in research and experiments, yielding significant results. Studying cavitation erosion in hydroelectric turbine systems presents a complex challenge for future research. Many parameters and features still require further investigation. All the discussed studies have established that cavitation phenomena require state-of-the-art equipment for their detection and visualisation. Moreover, more work is necessary for the numerical assessment of cavitation. Keywords: hydroelectric turbine, cavitation erosion, computational fluid dynamics.

Evaluating Vegetation Effects on Wave Attenuation and Dune Erosion during Hurricane

This study employs the XBeach surfbeat model (XBSB) to explore the effects of vegetation on wave attenuation and dune erosion in a case study of Mexico Beach during Hurricane Michael. The XBSB model was validated against laboratory experiments of wave-induced dune erosion and wave attenuation by vegetation. In the case study of vegetation on dunes in Mexico Beach during Hurricane Michael, different vegetation drag coefficients were evaluated to investigate the effects of vegetation on wave attenuation and dune erosion. LiDAR data of dune profiles before and after Hurricane Michael were used for model validation. The findings reveal that vegetation on dunes significantly affects wave attenuation and dune erosion. Under vegetated conditions, as the vegetation drag coefficient value increases, wave attenuation also increases, leading to a reduction of dune erosion. An increase in vegetation density enhances wave attenuation in the vegetated area, including reductions in significant wave height and flow velocity. However, the rate of change in attenuation decreases as the vegetation density increases. Through simulations under regular wave condition on Mexico Beach, an optimal vegetation density was identified as 800 units/m2. Beyond this density, additional vegetation does not substantially improve wave attenuation. Furthermore, the position of the dune crest elevation is related to the location where the alongshore flow velocity begins to decrease. The findings highlight the essential role of coastal vegetation in enhancing coastal resilience against hurricanes.

Soil Erosion Thickness and Seasonal Variations Together Drive Soil Nitrogen Dynamics at the Early Stage of Vegetation Restoration in the Dry-Hot Valley.

By changing the physicochemical and biological properties of soil, erosion profoundly affects soil nitrogen levels, but knowledge about the erosion impact on soil nitrogen (N) dynamics is still rather incomplete. We compared soil N contents at the early stage of vegetation self-restoration in response to soil erosion thickness (0, 10, 20, 30 and 40 cm), by conducting a simulated erosion experiment on sloping arable land in the dry-hot valley of Yunnan Province, southwestern China. The results showed total nitrogen (TN), ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) contents reduced with increasing soil erosion thickness and decreased significantly at the soil erosion thickness of 10, 40 and 10 cm in the rainy season and 30, 10 and 10 cm in the dry season compared with 0 cm. Structural equation modeling (SEM) indicated that soil erosion thickness and seasonal variation were the important drivers of mineral nitrogen (NH4+-N and NO3--N) content. Soil erosion thickness indirectly affected mineral nitrogen through negative on TN, carbon content and Diazotrophs (nifH genes). Dry-wet season change had an effect on mineral nitrogen mediated by arbuscular mycorrhizal fungi (AMF) and nifH genes. We also found AMF had a promotion to nifH genes in eroded soil, which can be expected to benefit nitrogen fixing. Our findings highlight the importance of considering soil erosion thickness and sampling time for nitrogen dynamics, in particular, the investigation of nitrogen limitation, in the early stage of vegetation self-restoration.

A novel strategy for design of mechanically robust antifouling coatings via bifunctional domain engineering

The issue of biofouling on marine structures carries significant economic and ecological implications, necessitating the development of effective and durable antifouling coatings. Traditional organic antifouling coatings often struggle with mechanical robustness in harsh marine environments, making them fragile and highly susceptible to abrasion. To address these challenges, we propose a novel “bifunctional domain engineering” strategy for designing robust antifouling coatings that combines excellent mechanical strength of a Fe-based amorphous layer and high antifouling efficacy of an incorporated organics. The hard domains consist of Fe-based amorphous micro humps, providing a sturdy framework that enhances the coating's mechanical durability. In contrast, the soft domains comprise epoxy resin infused with Cu2O and 4,5-Dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), offering a dual-action antifouling function via controllable antifouling agent release. Evaluation of antifouling performance by lab tests against Pseudomonas aeruginosa, Staphylococcus aureus, and Chlorella algae and practical marine field tests (for 150 days) demonstrates significant reductions in bacterial and algal adhesion (nearly 100 % resistance) with the bifunctional domain engineered coating (referred to as HSR coating), compared to pure amorphous coating. Mechanical durability tests, including abrasion and erosion experiments, underscore the HSR coating's excellent wear resistance. Importantly, the HSR coating maintains its outstanding antifouling properties even after 1000 abrasion cycles, highlighting its potential for long-term marine applications in harsh conditions. This study lays the groundwork for design of robust antifouling coatings capable of withstanding the harsh operating environments while effectively combating biofouling.

Improving the reliability of using rare earth elements as soil erosion tracers

Rare earth elements (REEs) have been successfully used as tracers in field-scale erosion experiments to provide spatially distributed erosion data for process-based soil erosion models. This study aimed to demonstrate how differences in the erodibility of individual REEs naturally present in the soil affect the evaluation of data from such experiments.A four-year field experiment was carried out at an experimental site used for arable farming to investigate soil erosion. The concentrations of tracer REEs (Pr, Sm, Gd, Ho, Er, and Yb) and reference REEs (all other REEs) were evaluated and compared both in the soil and eroded sediment.The tracer REE concentrations in the eroded sediments were consistently significantly higher than the average background soil concentrations. Even when compared with the maximum values of background soil concentrations, enrichment of Er, Sm, and Ho in the sediment was still evident. However, in some cases, the reference REE concentrations in the sediment were often higher than the maximum soil background concentrations by more than 10%. These enrichment differences indicate the varying erodibility of individual REEs during erosion. The elements chosen as tracers could also be enriched in the sediment from their natural background sources, thus influencing the measured concentration values in the sediment after tagging.This study demonstrated that different REEs naturally present in soil exhibit varying degrees of erodibility, which affects data evaluation in soil erosion tracing experiments using REE oxides as tracers. Therefore, the reliable application of the REE tracer method can only be suggested under certain requirements defined in this study.

A Study of Cavitation Erosion in Artificial Submerged Water Jets

The artificially submerged cavitation water jet is effectively utilized by ejecting a high-pressure water stream into a low-pressure water stream through concentric nozzles and utilizing the cavitation phenomenon generated by the shear layer formed between the two streams. In this study, we investigated the cavitation characteristics of artificially submerged cavitation water jets by combining numerical simulations and erosion experiments. The results indicate that an appropriate standoff distance can generate more cavitation clouds on the workpiece surface, and the erosion characteristics of the artificially submerged cavitation water jet are most pronounced at a dimensionless standoff distance of SD = 30. The shear effect formed between the two jets plays a crucial role in generating initial cavitation bubbles within the flow field of the artificially submerged cavitation water jet. Moreover, increasing the convergent angle between the two jets can significantly enhance the cavitation effect between them and lead to a more substantial cavitation effect. Simultaneously, increasing the pressure of the high-pressure inner nozzle also contributes to enhancing the cavitation effect of the artificially submerged cavitation water jet.

Investigation on critical erosion of gas production channel for sand carrying during injection and production process in gas storage

Gas wells on underground gas storage typically are operated in high-load mode, with a large working displacement injection and high-strength production. Erosion-corrosion caused by solid particles could cause serious damage to the gas well, leading to tubing column failure and security risks. The influence factors on the tubing column geometry, the fluid properties and particle properties were investigated by the indoor erosion experiments and numerical simulation respectively. Five different erosion models were applied to predict the erosion rate. The Generic model was selected to calculate the influencing value by a range of parameters after comparing the predicted results with the experimental data. The results indicated that the sand production rate, the gas production rate and the production pressure played a crucial role on the tubing column erosion. The error of Generic model is less than 20%. The product of the quadratic power of daily gas production, the negative quadratic power of production pressure and the first power of sand production rate was directly proportional to the erosion rate of tubing column. The sequence of the maximum erosion rate on different sites from high to low was obtained: No-Go Landing Nipple, Safety Valve, integral Y-type wellhead. The erosion effect on Y-type wellhead should be considered emphatically considering the long-term operation. The chart of Critical Erosion Coefficient (C value) was established according to the design criterion of API RP 14E, which is suitable for gas storage production channel. The reasonable C value should be set as 180.0 to ensure the gas storage to meet the service life. Meanwhile, the recommendatory C value range was set between 175.0 and 200.0 for considering the maximum productivity of gas storage. The research results provided a key guidance for judging the service safety of injection-production channel in gas storage.

Prediction of gas–solid erosion wear of bionic surfaces based on machine learning and unimodal intelligent optimization algorithm

Solid particle erosion wear is an inevitable phenomenon in industrial production, with erosion removal mass serving as a crucial metric for assessing the wear rate per unit area on the impacted surface. Developing predictive models to estimate the degree of mass removal is crucial for effectively controlling, evaluating, and preventing severe damage resulting from solid particle erosion wear. In this study, we constructed a comprehensive dataset comprising smooth and bionic surfaces, encompassing inner, outer, and planar surfaces. The dataset was used in a multifactorial erosion experiment, considering adjustable erosion angles, solid particle incident gas velocities, and solid particle diameter sizes. Through visualization and analysis of the obtained dataset, we identified optimal scenarios for bionic surface erosion resistance, offering insights for structural design against bionic erosion resistance. Furthermore, we compared machine learning algorithms to address the prediction problem, resulting in the selection of the best-performing regression algorithm, SVR (Support Vector Regression). Additionally, we compared the performance of other advanced intelligent optimization algorithms using unimodal benchmark functions, finding that HHO (Harris Hawks Optimization) emerged as the optimal choice for unimodal optimization. Building on HHO, we developed the IHHO (Improved Harris Hawks Optimization)-SVR model, using experimental data from erosion tests as the training dataset. This model can predict gas–solid two-phase flow erosion patterns, encompassing various wall types, solid particle sizes, solid incident gas velocities, and impact angles. Due to its robustness and rapid prediction capabilities, the model is expected to serve as a cost-effective tool for predicting erosion removal mass in gas–solid two-phase flow scenarios.

The soft overcoming the hard-an erosion control method for elbow: Experiments and numerical simulations

A novel approach to alleviate erosion by adding water, based on the principle of the soft overcoming the hard, was investigated through self-designed erosion experiments and computational fluid dynamics (CFD) simulations. The results demonstrate that adding a liquid phase to the elbow significantly reduces the erosion rate. The erosion inhibition efficiency is positively correlated with the liquid phase content, reaching 81.56 % in the most severe erosion zone during the experiments. The liquid film can increase the drag force and reduce the particles' impact velocity. Rather than exacerbating erosion, the liquid film enables easier particle accumulation and mitigates erosion instead.

A comprehensive investigation of uncertainties in cavitating waterjet experiments

This paper systematically examines the sources of uncertainty in cavitating waterjet test setups and provides illustrative case studies to conduct thorough uncertainty analyses for erosion tests using cavitating waterjet method. Within this study, utilizing examples of uncertainty analysis presented by the International Towing Tank Conference (ITTC) for various testing techniques, a novel uncertainty analysis implementation suitable for cavitating waterjet tests has been conducted. Firstly, cavitation erosion experiments were carried out on samples aluminum (Al 6063) material under cavitation number conditions (σ = 0.02 to σ = 0.033 range) as part of the validation study. Subsequently, within the scope of uncertainty analysis calculations, five erosion tests were conducted for each of the two different cavitation numbers (σ = 0.03 and σ = 0.05). The study aims to examine the bias and precision uncertainty components separately for the test results of erosion rate and establish a reliable and repeatable procedure for predicting the uncertainty level of cavitating waterjet tests. For the first time in the literature, the uncertainty components of cavitating waterjet tests were investigated in detail and the uncertainty level in cavitating waterjet tests, including bias and precision errors, was predicted in accordance with specific ITTC guidelines and procedures. Based on the results, the primary bias error source was identified as the pressure inside the cavitation chamber, with the nozzle pressure being the second most significant bias error source. Consequently, it is recommended to perform the bias error prediction based on the ratio of these two, known as the cavitation number. Precision error, crucial for uncertainty, was estimated using five sets of erosion rate values, emphasizing its importance in cavitating waterjet tests. It is anticipated that the suggested methodology will serve as a benchmark for predicting uncertainty levels in cavitating waterjet tests.

Parametric appraisal and wear prediction of hybrid composites using an integrated soft computing approach

AbstractThis article reports on the implementation of artificial neural network (ANN) and statistical methods to analyze and predict the erosion performance of titania (TiO2) filled ramie‐epoxy based composites. These hybrid composites are prepared by conventional hand lay‐up route and subjected to solid particle erosion tests as per Taguchi's L27 orthogonal array. The effects of different control factors on erosion rate of these composites are studied using Taguchi method. It reveals that impact velocity and filler content have significant effect on the erosion wear rate followed by other least significant factors. The individual effect of each control factor while keeping other factors constant is ascertained by performing steady state erosion experiments. Further, a computational model based on ANN is used as a tool to effectively predict the erosion rates of the composites. The results show that the predicted values are in reasonably good agreement with the experimental ones with an accuracy of 90% and relative error lying within a range of 1%–10%. Further, the trained ANN model is validated by considering the erosion rates obtained during steady state erosion process as the input parameter. The possible mechanisms causing the wear loss are identified using electron microscopy.Highlights Successful fabrication of titanium oxide reinforced hybrid composites. Steady state erosion experiments are performed. Erosion rates are predicted using ANN and compared with the experimental data. Wear loss mechanisms are identified using electron microscopy.

Study on Dynamic Evolution and Erosion Characteristics of Cavitation Clouds in Submerged Cavitating Water Jets

The dynamic evolution behavior of submerged water jet cavitation clouds was studied by combining experiments and simulation. The formation, development, shedding, and collapsing process of a void cloud was analyzed by high-speed camera technology, and the influence of jet pressure was studied. Cavitation water jet erosion experiments were carried out on AL6061 specimens with standard cylindrical nozzles, and the correlation between cavitation cloud evolution and material erosion was studied by surface analysis. The results showed that the evolution of a cavitation cloud has obvious periodicity, that one period is about 0.8 ms, and its action region can be divided according to the attenuation rate of the jet velocity of the nozzle axis. The attenuation rate of the jet velocity at the nozzle axis in the central jet action zone is less than or equal to 82.5%, in the mixed action zone greater than 82.5% and less than 96%, and in the cavitation action zone greater than or equal to 96%. The erosion damage characteristics in different regions of the mixed action zone are significantly different.

Research on the solid particle erosion wear of pipe steel for hydraulic fracturing based on experiments and numerical simulations

Erosion wear is a common failure mode in the oil and gas industry. In the hydraulic fracturing, the fracturing pipes are not only in high-pressure working environment, but also suffer from the impact of the high-speed solid particles in the fracturing fluid. Beneath such complex conditions, the vulnerable components of the pipe system are prone to perforation or even burst accidents, which has become one of the most serious risks at the fracturing site. Unfortunately, it is not yet fully understood the erosion mechanism of pipe steel for hydraulic fracturing. Therefore, this article provides a detailed analysis of the erosion behavior of fracturing pipes under complex working conditions based on experiments and numerical simulations. Firstly, we conducted erosion experiments on AISI 4135 steel for fracturing pipes to investigate the erosion characteristics of the material. The effects of impact angle, flow velocity and applied stress on erosion wear were comprehensively considered. Then a particle impact dynamic model of erosion wear was developed based on the experimental parameters, and the evolution process of particle erosion under different impact angles, impact velocities and applied stress was analyzed. By combining the erosion characteristics, the micro-structure of the eroded area, and the micro-mechanics of erosion damage, the erosion mechanism of pipe steel under fracturing conditions was studied in detail for the first time. Under high-pressure operating conditions, it was demonstrated through experiments and numerical simulations that the size of the micro-defects in the eroded area increased as the applied stress increased, resulting in more severe erosion wear of fracturing pipes.