Erosion Damage Research Articles

Machine learnt prediction method for rain erosion damage on wind turbine blades

AbstractThis paper proposes a paradigm shift in the numerical simulation approach to predict rain erosion damage on wind turbine blades, given the blade geometry, its coating material, and the atmospheric conditions (wind and rain) expected at the installation site. Contrary to what has been done so far, numerical simulations (flow field and particle tracking) are used not to study a specific (wind and rain) operating condition but to build a large database of possible operating conditions of the blade section. A machine learning algorithm, trained on this database, defines a prediction module that gives the feature of the impact pattern over the 2‐D section, given the wind and rain flow. The advantage of this approach is that the prediction becomes much faster than using the standard simulations; thus, the study of a large set of variable operating conditions becomes possible. The module, coupled with an erosion model, is used to compute the erosion damage of the blade working on specific installation site. In this way, the variations of the flow conditions due to dynamic effects such as variable wind, wind turbulence, and turbine control can be also considered in the erosion computation. Here, we describe the method, the database creation, and the development of the prediction tool. Then, the method is applied to predict the erosion damage on a blade section of a reference wind turbine, after one year of operation in a rainy onshore site. Results are in good agreement with on field observations, showing the potential of the approach.

Chemical characterization and anti-arthritic appraisal of Monotheca buxifolia methanolic extract in Complete Freund's Adjuvant-induced arthritis in Wistar rats.

The current study was designed to evaluate the anti-oxidant and anti-arthritic potential of a traditionally used herb, Monotheca buxifolia. The M. buxifolia methanolic extract (MBME) was prepared from the aerial parts of the plant followed by chemical characterization with GC-MS. The anti-oxidant potential of the MBME was demonstrated by DPPH scavenging activity. The effects of MBME on protein denaturation and membrane stabilization were determined by inhibition of egg albumin denaturation and RBC membrane stabilization assays, respectively. The in vivo anti-arthritic potential of the MBME at 50, 100, and 150mg/kg/day was evaluated in Complete Freund's Adjuvant-induced polyarthritis in Wistar rats treated for 21days. Phytochemicals, such as linolenic acid methyl ester, n-hexadecanoic acid, vitamin E, α-amyrin, and β-amyrin were detected in the GC-MS analysis. The plant extract exhibited a 55.20 ± 0.69% scavenging of free radicals at 100µg/ml concentration. It significantly (p < 0.05) stabilized human RBC membrane (65.06 ± 0.22%) and inhibited protein denaturation (70.53 ± 0.34%) at 100mg/ml concentration. The diclofenac sodium (DS) and MBME at 150,100, and 50mg/kg reduced the paw edema, restored the body weight, and altered blood parameters including CRP. The MBME significantly reduced the MDA and increased the SOD, CAT, and GSH levels in liver tissue homogenate in treated rats. The serum concentration of TNF-α and PGE2 was remarkably (p < 0.01-< 0.0001) restored by the DS and MBME dose dependently. The histopathological study showed that MBME 150mg/kg commendably restored the ankle joint inflammation, bone erosion, and cartilage damage in polyarthritic rats. It was concluded that the anti-oxidant, anti-inflammatory and anti-arthritic effects of MBME might be attributed to phenols, flavonoids, triterpenoids, vitamin E, phytol, and other fatty acids. This study showed the anti-arthritic potential of Monotheca buxifolia and thus validates its traditional claim.

Quantifying erosion hazards and economic damage to critical infrastructure in river catchments: Impact of a warming climate

Climate change is projected to cause considerable pressure on our environment and communities. In particular, an increase in flooding and extreme erosion events is foreseeable as a result of an anticipated increase in the frequency and severity of storms. In the absence of timely and strategic intervention, climate change is taking us closer to more uncertain (non-linear, stochastic) and potentially more catastrophic climatic impacts. This paper develops a state-of-the-art modelling framework to assess the economic impact of erosion hazards on critical infrastructure and evaluate their vulnerability and resilience to differing storm regimes. This framework is trialled on a UK town (Cockermouth, NW England) that has experienced significant storm-related erosion and flood damage in recent years, highlighting its ability to determine current and future erosion hazard to critical infrastructure. A hydro-sedimentary model is used to simulate fluvial and hillslope sediment erosion and deposition caused by extreme storms within river catchments (sheet, rill, gully and channel bank and bed erosion). The model is applied for current climate conditions and for two future epochs (2021–2040 & 2061–2080) to assess changing erosion hazard to critical infrastructure. Climate conditions for the two epochs are obtained using the UKCP18 high resolution realisation projections under emission scenario RCP8.5. The economic loss caused by these hazards is projected based on new, non-linear depth-cost curves derived from previous assessments. The results show that: 1) due to a warming climate, total rainfall in the Cockermouth area (and likely across the UK) may be higher for all storm durations and annual exceedance probabilities, until epoch 2061–2080 when the rainfall regime may shift towards shorter duration events with higher rainfall and longer duration events with less rainfall; 2) the total area that undergoes flooding, erosion and sediment deposition, and the magnitude of the hazard, may increase as the climate shifts; 3) the economic damage caused by erosion and deposition is positively related to rainfall total, and the highest costs are likely to be associated with damage caused to bridges (£102-130 million), followed by sediment deposition in the urban fabric (£9-82 million), and erosion damage to agricultural land (£16-26 million), buildings (£0.4-18 million) and roads (£0.4-4 million); and 4) the Estimated Annual Damage costs suggest that investment in bridges (£4-6 million) in the Cockermouth area is required now to ensure their resilience to extreme storm events, and interventions are likely to be needed within the next 20 years to prevent high economic costs associated with significant sediment deposition in the urban fabric (£0.3-4 million) and damage to roads (£0.08-0.1 million) and agricultural land (£0.6-2 million). This new framework can help support operational (immediate) and strategic (medium to long term i.e. 10+ years) erosion control decision making through the provision of an assessment of the scale and consequences of erosion.

Repair of Turbine Components by Abrasive-Jet Machining

In the operation of modern gas and steam turbines, the amount of deposits on the aggregate surfaces inevitably increases (mainly in the form of amorphous silicon), which leads to metal corrosion and erosion damage. The relevance of solving the problem of removing technological pollution in the process of repairing gas and steam turbines in order to restore the design capacity of the equipment is shown in this paper. The efficiency of using hydroabrasive treatment for performing repair operations on turbine components (rotors, blades, etc.) has been established. The method developed is an alternative to the chemical cleaning processes and mechanical surface abrasion. The technology does not have a negative effect on the environment and has an isolated system of using technological components. The technology (composition of the technological medium) and equipment (high speed and density of particles) provide cleaning of deposits from the gas and steam turbine components, in particular, turbine blades, with a high quality of the resulting surface and the required productivity.

Microwave cladding for slurry erosion resistance applications: A review

With the growing energy need, hydro power becomes the most outstanding source of renewable, clean and affordable energy. However, slurry erosion of underwater components reduce the overall efficiency of the power generating system, thus, fails to fulfil energygoalsentirely. To prevent erosion damage, protective coatings are highly recommended. In present study, response of microwave cladding against slurry erosion wear is reviewed. The effects of process parameters such as microwave power and exposure time are discussed in detail. Microwave cladding of different material systems and their slurry erosion performance are also summarized.

Research on the Mechanism Model of Carbon Composite Material Damaged by Erosion in the Thermal Field of Single Crystal Silicon Furnace

Aiming at the problem of the short service life of the carbon/carbon pot wall caused by continuous silicification during the pulling process of single crystal silicon, the paper analyzes the failure mode of the carbon/carbon pot wall and analyzes the influence of the pot wall in the single crystal silicon furnace thermal field. The mechanism of erosion damage. It is concluded from the use situation that the carbon/carbon composite crucible can be used in the field of Czochralski single crystal silicon, and its performance is far better than that of the graphite crucible, and the destruction mechanism of the carbon/carbon composite crucible is analyzed, and solutions are proposed. Through the analysis of the entire industry, carbon/carbon composite crucibles will replace graphite crucibles and become the preferred material for the thermal field of Czochralski silicon single crystals in the future.

Electrochemical Characteristics with Cavitation Amplitude under Cavitation Erosion of 6061-T6 in Seawater

Generally, Al alloys of 5000 and 6000 series show excellent weldability, workability, and specific strength, and are widely used in ship building. A combined experiment via cavitation erosion and corrosion damage involving 6061-T6 Al alloy was performed using potentiodynamic polarization under cavitation erosion (hybrid experiments) with amplitude (cavitation strength). The corrosion current density was approximately 52-fold higher at 30 μm than under static conditions, suggesting that the amplitude greatly affected the damage. The degree of damage increased with increasing cavitation amplitude. After the hybrid experiment, the corrosion rate was compared according to the weight loss and damage depth, and the relationship between the two values was expressed as alpha value. The alpha (α) values at amplitudes of 5 μm, 10 μm and 30 μm were 5.11, 12.81 and 8.74, respectively, suggesting that the α value at 10 μm was greater than at 5 μm, and indicating local corrosion damage. However, the α value at 30 μm was smaller than that of 10 μm, which is attributed to higher damage via uniform corrosion than damage induced by local corrosion.

Investigation of the Erosion Damage Mechanism and Erosion Prediction of Boronized Coatings at Elevated Temperatures.

In this study, the high temperature erosion mechanisms and damage characteristics of a boronized coating have been systematically studied by employing an improved high-temperature accelerated erosion test bench and impact contact theory analyses. Within the scope of the experimental parameters, the erosion rate of the boronized coating under the same erosion conditions was observed to be only one half to one-twelfth of the erosion rate of the substrate. Furthermore, the boronized coating was noted to be less sensitive to the speed of the erosion particles than the plastic substrate, thus, indicating superior and more stable erosion resistance than the base material. The boronized coating exhibited typical brittle fracture characteristics under impact by the high-speed particles. When the particle impact normal stress exceeded the critical stress for crack propagation owing to the coating defects, the surface and subsurface layers of the coating initially formed horizontal and vertical micro-cracks, followed by their gradual expansion and intersection. After destabilization, the brittle coating material was peeled layer-by-layer from the surface of the test piece. At the same incident speed, as the particle size was increased from 65 μm to 226 μm and 336 μm, the size (width) of the erosion cracks on the coating surface increased from 1 μm to 30 μm and 100 μm respectively. Correspondingly, the erosion damage thickness of the coating was enhanced from 15 μm to 50 μm and 100 μm. In the case of the quartz sand particle size exceeding 300 μm, the dual-phase boronized coating did not provide effective protection to the substrate. Furthermore, based on the elastoplastic fracture theory, a prediction model for the erosion weight loss of the boronized coatings within the effective thickness range has been proposed in this study.

COMPENSATION AND COASTAL PROTECTION

In this presentation, the authors examine the circumstances in which public bodies and professionals retained by them can be liable to pay monetary compensation for erosion damage. Coastal engineering, together with the analysis of coastal processes, play an important role in this legal landscape. Public bodies may come under a duty to implement defensive works; but equally they may be responsible for adverse impacts from them, such as end effects erosion. Coastal engineers may be engaged to provide critical protective works; but they may be liable where works are not designed or built to required standards or for stipulated purposes. Difficulties in assessing likely risk due to changes associated with climate change add an additional dimension with the increased risk of failure of protective works facing conditions which may not have previously been considered in the design criteria. Drawing from a decade of experience acting for litigants and property owners in erosion hotspots in New South Wales, the authors identify the key principles that apply in Australia and other common law jurisdiction and discuss how these rules can apply to scenarios where a disaster arises on any coastline. Some of the cases covered were included in the 2017 review by the United Nations entitled "The Status of Climate Change Litigation".

Indolent T-cell lymphoproliferative disorder of the gastrointestinal tract managed conservatively with corticosteroids

An 82-year-old female presented with a 4-week history of abdominal pain, weight loss, diarrhea, and nausea. A complete infectious workup was negative. Her computed tomography (CT) scan showed no pathologic changes and her esophagogastroduodenoscopy (EGD) showed erosive damage in the duodenum. Her duodenal biopsy showed inflammation with a marked increase in intra-epithelial lymphocytes and her immunohistochemistry was consistent with indolent T-cell lymphoproliferative disorder of the gastrointestinal tract. She was started on high dose steroids three months after the onset of her symptoms. She gradually improved with complete resolution of erosive changes on her repeat EGD.

Prediction of crater depth, surface roughness and erosion rate during abrasive jet machining of glass

Understanding the mechanism for brittle material removal via solid particle impact is important for various areas such as energy and aerospace industries. The existing analytical formulation of erosion damage, consistent with indentation fracture theory, overestimates actual erosion by over 200%. This study complements an existing analysis by prescribing a realistic shape and mechanical properties to the impinging particle. We quantitatively show that a lateral crack in glass does not nucleate at the indenter's tip or the theoretical plastic depth, but at an intermediate depth. This depth can be found by implementing the actual particle penetration depth into Hill's ratio. Several new geometries of the particle's impacting tip are proposed as ways to achieve adequate particle penetration depth instead of an expanding hemispherical cavity. The crater depth, surface roughness, and erosion efficiency of borosilicate glass are predicted with 10%, 24%, and 23% error, respectively, using a simple analytical routine.

Cavitation erosion behavior of GH 4738 nickel-based superalloy

Cavitation erosion is a form of wear damage, and reduces the performance and lifetime of the components that used in aerospace, power and nuclear industries, etc. The cavitation erosion behavior of GH 4738 nickel-based superalloy was investigated using an ultrasonic vibratory device and compared with that of Inconel 601 alloy. The results show that GH 4738 exhibited better cavitation erosion resistance than Inconel 601. The selective cavitation erosion and cavitation-induced nanometer-scaled precipitates were found on the eroded surface of GH 4738. The erosion damage might be slowed down through the bubbles collapse energy absorption by the formation of precipitates and the pinning effect of precipitates, which will be helpful to understand the effect of precipitates on materials cavitation erosion resistance.

Modelling and prediction of cavitation erosion in GDi injectors operated with E100 fuel

Ethanol (E100) can be utilised in spark ignition engines for passenger car vehicles. This brings a challenge to the durability of the fuel injection system components since its use can result in corrosion, further enhanced by cavitation-induced erosion. This work reports computational fluid dynamics (CFD) predictions for both the flow development and the locations prone to cavitation erosion in multi-hole gasoline direct injection (GDi) injectors operated with E100. The compressible form of the Navier–Stokes equations is solved numerically considering the motion of the injector’s needle valve. Thermodynamic and mechanical equilibrium is assumed between the liquid, vapour and non-condensable gas; E100 liquid and vapour are considered as a barotropic fluids where the corresponding variation in density with pressure and the speed of sound are estimated via a relevant equation of state; an additional transport equation is solved for simulating the non-condensable air entrainment into the injector during the dwell time between successive injections. Turbulence is modelled using both large eddy simulation (LES) and Unsteady Reynolds-averaged Navier–Stokes (URANS) considering a sector and the full nozzle geometry, respectively. Various cavitation erosion indices reported in the literature are evaluated against new durability tests of surface erosion damage obtained after 400 M injection cycles. The relevant nozzle wall erosion images are found to correlate well with the accumulated erosive power predicted from the computational model.

Experimental study on erosion behavior of fracturing pipeline involving tensile stress and erosion prediction using random forest regression

Damage induced by erosion wear is an inevitable problem in the oil and gas industry. During the hydraulic fracturing operation, the fracturing pipeline is not only subjected to tensile stress caused by the high internal pressure, but it also inevitably suffers from erosion damage from solid particles carried by the fracturing fluid. Due to the lack of accurate erosion prediction methods for fracturing pipelines in operation conditions, it is difficult to prevent the failure of pipe fittings caused by erosion wear. Therefore, in this paper, erosion wear experiments of fracturing pipelines under varying conditions (including impact angle, tensile stress, target material, flow velocity and particle concentration) were carried out. Results indicate that the tensile stress plays a crucial role in affecting the erosion wear rate. Furthermore, erosion wear prediction models were proposed on basis of the sufficient experimental data by using different machine learning algorithms. The prediction results were validated in comparison with experiments via error analysis. A good performance in prediction accuracy and generalization ability was observed in the random forest regression (RFR) approach, making it a potential solution in predicting the slurry erosion wear of fracturing pipelines and may be developed to all the high-pressure pipelines.

15928 Reduced time to onset of psoriatic arthritis is associated with specific phenotypes and psoriatic characteristics

Psoriatic arthritis (PsA) is a chronic inflammatory condition characterized by joint damage in approximately 20% of psoriasis (Ps) patients. Delaying treatment as little as six months after PsA onset can result in irreversible, erosive joint damage. The study objective was to identify factors associated with early onset PsA in people with psoriasis. Using data from November 2002 through January 2019 in the Utah Psoriasis Initiative (UPI) registry, we searched for patient characteristics associated with shorter latency periods between Ps and PsA onset. Our dataset includes 342 patients with rheumatologist-diagnosed PsA either prior to or subsequent to enrollment and 692 with cutaneous Ps without PsA until the last recorded follow-up time. Using a Cox regression model, we identified features associated with a shorter latency period between Ps and PsA onset. FDR-adjusted P values are reported here. There is an association between higher scores of three key clinical indicators of psoriasis severity and reduced latency period to PsA onset: erythema (P = .012, HR 1.179 [95% confidence interval 0.07-0.26]), induration (P < .001, HR 1.206 [010-0.27]), and desquamation (P = .019, HR 1.145 [0.05-0.22]). Other associated phenotypic features included fingernail involvement (P < .001, HR 1.904 [0.43-0.86]), any nail involvement (P < .001, HR 1.710 [0.31-0.77]), pustular psoriasis (P = .006, HR 2.026 [0.31-1.10]), psoriasis in the groin (P = .043, HR = 1.389 [0.09-0.57]), palmar plantar pustular psoriasis (P = .022, HR 2.299 [0.29-1.38]), higher body mass index (BMI) at age 18 (P = .024, HR 1.035 [0.01-0.06]), and depression (P = .013, HR 1.486 [0.16-0.63]). These phenotypic and demographic features may be indicators for an elevated risk of early onset PsA, and could be considered for PsA screening and referral strategies to a rheumatologist.

Studies on solid particle erosion by HVOF sprayed 25% (Cr3C2-25 (Ni20Cr)) + 75% NiCrAlY on Ti-31

Solid particle erosion is an important material degradation mechanism occurs in thermal power plants, aircraft gas turbine engines. When gas turbine components like compressors, blades and vanes working under high temperature, Erosion wear occurs by impact of solid particles like coal ash and unburnt carbon particles. In this present research work the solid particle erosion studied on uncoated samples (Ti-31), and HVOF sprayed 25% (Cr3C2-25 (Ni20Cr)) + 75% NiCrAlY powder on Ti-31. Erosion studies are done with impact angles of 30°, 60° and 90°. Solid particle erosion studies were carried out using air jet erosion test rig as per ASTM G76-02 standard. All the three angles of uncoated alloys exhibit erosion damage under ductile mode and less amount of erosive loss compared HVOF coated samples. The HVOF sprayed coated Ti-31 at various impact angles is brittle mode. The mechanism of material removal during erosion of brittle materials is explained by using SEM micrographs. Erosion is controlled by using selected coating powder.

Effect of radiographic disease severity in high-resolution quantitative computed tomography assessment of metacarpophalangeal joint erosion and cysts.

Bone erosions are the hallmark of rheumatoid arthritis (RA). High-resolution peripheral quantitative computed tomography (HR-pQCT) enables 3-dimensional visualization of arthritic bone erosions at a high resolution. However, the degree of erosive disease could influence the reliability of HR-pQCT evaluation. We aim to assess the intra- and inter-reader variability of identification of erosions in the metacarpophalangeal (MCP) joints using HR-pQCT in healthy controls and patients with RA, stratified according to van der Heijde-modified Sharp Score (HSS) of radiographic erosions. We analyzed HR-pQCT images from 78 patients with RA and 25 healthy controls. Patients were allocated to one of three groups of mild, moderate or severe disease according to HSS of MCP joints 2 and 3. Total HR-pQCT scans were analyzed twice in random order by three experienced readers, blinded to group distribution. The number of cortical interruptions and their classification as either erosions or cysts according to predefined criteria were recorded. Intraclass correlation coefficients (ICC) for cortical interruptions, erosions and cysts were calculated for each group using a 2-way random-effects model for inter-reader ICC and a 2-way mixed-effects model for intra-reader ICC. The intra- and inter-reader ICC were good to moderate for cortical interruptions and moderate for erosions throughout disease severity groups. The ICCs for the identification of cysts decreased with increasing degree of erosive disease. The detection of cortical interruptions is only minimally affected by the degree of erosive damage, whereas the distinction between erosions and cysts is more complex in patients with extensive erosive disease.

CFD numerical simulation of standalone sand screen erosion due to gas-sand flow

Solid particles entrained in produced gas cause erosive damage in production and transportation facilities, that may eventually impact any process safety. The main purpose of this research is to determine the point on the Standalone screen (SAS) surface, where erosion rate is critical and to evaluate the uncertainties in the calculations and predictions of sand screen erosion utilizing CFD numerical simulation. A k-epsilon model was implemented to solve gas flow behavior and Discrete Phase Model (DPM) was used to track solid particles. The results of DPM were then introduced to conduct erosion simulation on the SAS utilizing four erosion equations. A full presentation of particle velocity vectors, particle velocity streamlines, total pressure contours and wall shear stress contours on the screen surface are presented and discussed. Additionally, the particle traces and path-lines are also demonstrated based on particles residence time as part of the particles’ trajectories. The erosion rates and erosion patterns from the four erosion equations, have shown similarities in their response to the change of sand characteristics. Considering the change in solid particles properties, a good agreement between CFD predictions and published data is achieved. This research can be used as a basis to offer safe operating guidelines for wells that are completed using standalone sand screens (SAS).

Assessment of Freeze–Thaw Hazards and Water Features along the China–Russia Crude Oil Pipeline in Permafrost Regions

The China–Russia crude oil pipeline (CRCOP) traverses rivers, forests, and mountains over permafrost regions in northeastern China. Water accumulates beside the pipe embankment, which disturbs the hydrothermal balance of permafrost underlying the pipeline. Ground surface flows along the pipeline erode the pipe embankment, which threatens the CRCOP’s operational safety. Additionally, frost heave and thaw settlement can induce differential deformation of the pipes. Therefore, it is necessary to acquire the spatial distribution of water features along the CRCOP, and analyze the various hazard probabilities and their controlling factors. In this paper, information regarding the permafrost type, buried depth of the pipe, soil type, landforms, and vegetation were collected along the CRCOP every 2 km. Ponding and erosive damage caused by surface flows were measured via field investigations and remote sensing images. Two hundred and sixty-four pond sites were extracted from Landsat 8 images, in which the areas of 46.8% of the ponds were larger than 500 m2. Several influential factors related to freeze–thaw hazards and erosive damage were selected and put into a logistic regression model to determine their corresponding risk probabilities. The results reflected the distributions, and forecasted the occurrences, of freeze–thaw hazards and erosive damage. The sections of pipe with the highest risks of freeze–thaw and erosive damage accounted for 2.4% and 6.7%, respectively, of the pipeline. Permafrost type and the position where runoff encounters the pipeline were the dominant influences on the freeze–thaw hazards, while the runoff–pipe position, buried depth of the pipe, and landform types played a dominant role in erosive damage along the CRCOP. Combined with the geographic information system (GIS), field surveys, image interpretation and model calculations are effective methods for assessing the various hazards along the CRCOP in permafrost regions.

Numerical Modeling of the Effects of Leading-Edge Erosion and Trailing-Edge Damage on Wind Turbine Loads and Performance

Abstract Wind turbines operate in challenging environmental conditions. In hot and dusty climates, blades are constantly exposed to abrasive particles that, according to many field reports, cause significant damages to the leading edge. On the other hand, in cold climates similar effects can be caused by prolonged exposure to hail and rain. Quantifying the effects of airfoil deterioration on modern multi-MW wind turbines is crucial to correctly schedule maintenance and to forecast the potential impact on productivity. Analyzing the impact of damage on fatigue and extreme loading is also important to improve the reliability and longevity of wind turbines. In this work, a blade erosion model is developed and calibrated using computational fluid dynamics (CFD). The Danmarks Tekniske Universitet (DTU) 10 MW Reference Wind Turbine is selected as the case study, as it is representative of the future generation wind turbines. Lift and Drag polars are generated using the developed model and a CFD numerical setup. Power and torque coefficients are compared in idealized conditions at two wind speeds, i.e., the rated speed and one below it. Full aero-servo-elastic simulations of the turbine are conducted with the eroded polars using NREL's BEM-based code OpenFAST. Sixty-six 10-min simulations are performed for each stage of airfoil damage, reproducing operating conditions specified by the IEC 61400-1 power production DLC-group, including wind shear, yaw misalignment, and turbulence. Aeroelastic simulations are analyzed, showing maximum decreases in CP of about 12% as well as reductions in fatigue and extreme loading.