Showing papers on "Turbine blade published in 2018"
TL;DR: In this paper, the authors investigate the impact of these parameters on the simulation results to guide the execution of accurate CFD simulations of VAWTs at different tip speed ratios (λ) and solidities (σ).
143 citations
TL;DR: In this paper, the performance of three wind-lens configurations with different diffuser types is investigated (i.e., flat-panel, curved-surface, and cycloidal-surface).
116 citations
TL;DR: The computational results prove the capability of the proposed monitoring approach in identifying impending blade breakages and validated by blade breakage cases collected from wind farms located in China.
Abstract: Monitoring wind turbine blade breakages based on supervisory control and data acquisition (SCADA) data is investigated in this research. A preliminary data analysis is performed to demonstrate that existing SCADA features are unable to present irregular patterns prior to occurrences of blade breakages. A deep autoencoder (DA) model is introduced to derive an indicator of impending blade breakages, the reconstruction error (RE), from SCADA data. The DA model is a neural network of multiple hidden layers organized symmetrically. In training DA models, the restricted Boltzmann machine is applied to initialize weights and biases. The back-propagation method is subsequently employed to further optimize the network structure. Through examining SCADA data, we observe that the trend of RE will shift by the blade breakage. To effectively detect RE shifts through online monitoring, the exponentially weighted moving average control chart is deployed. The effectiveness of the proposed monitoring approach is validated by blade breakage cases collected from wind farms located in China. The computational results prove the capability of the proposed monitoring approach in identifying impending blade breakages.
105 citations
TL;DR: Results indicate that the proposed Physics of failure-based reliability prediction method using multi-source information fusion has been developed and it can predict the reliability of aero engine turbine blades to be an interval by utilizing the proposed linear fusion algorithm.
103 citations
TL;DR: In this paper, a combination of CFD and Taguchi method is applied to optimize the aerodynamic performance of a typical three-bladed VAWT at a low TSR of 2.
98 citations
TL;DR: In this paper, the single-crystal nickel-based superalloys for high-pressure turbine blades and the γ-TiAl-based alloys for low pressure turbine blades are presented.
95 citations
TL;DR: In this article, a fault detection and diagnosis system that combines ultrasonic techniques with wavelet transforms for detecting ice on the blades was presented, where Lamb waves were generated with Macro Fibre Composites (MFC) and collected with MFC.
90 citations
TL;DR: In this paper, the authors assess the fatigue properties of Ti-6Al-4V samples designed with internal axial channels featuring a rough as-built surface and find that a relatively low scatter of fatigue lives is attributed to rapid crack initiation and, thus, the dominant influence of the (micro-) crack growth regime.
90 citations
TL;DR: In this paper, light and electron micrographs illustrating microstructures, which describe metallurgical phenomena in 3D printing/additive manufacturing of metal and alloy products and components, are presented along with extensive process and processing parameter descriptions and review.
Abstract: Applications and examples of light and electron micrographs illustrating microstructures, which describe metallurgical phenomena in 3D printing/additive manufacturing of metal and alloy products and components, are presented along with extensive process and processing parameter descriptions and review. Examples include microstructures that have defined turbine blade fabrication and optimization over the past half century, including contemporary electron beam melting fabrication of turbine blade alloys and other novel microstructures and architectures, which result from layer by layer, non-equilibrium melt solidification and epitaxial growth involving powder bed laser and electron beam fabrication. Phase transformations and second-phase formation by rapid cooling in metal and alloy components fabricated by laser and electron beam melting technologies are illustrated for a range of high-temperature materials. Using a range of examples, the advantages of fabricating complex (especially porous) biomedical and related commercial products are described. Prospects for future developments of direct 3D metal and alloy droplet printing, as a key component of the digital factory of the future, are described. This technology is compared with more conventional solidification and powder bed layer building thermo-kinetics, especially in the context of large structure and component fabrication.
89 citations
TL;DR: In this paper, the authors present a review of basic gas turbine heat transfer issues with advanced cooling technologies and documents important relevant relevant references for future research references, and propose a turbine blade cooling system with efficient cooling strategies under new harsh working environments.
Abstract: Gas turbines have been extensively used for aircraft engine propulsion, land-based power generation, and industrial applications. Power output and thermal efficiency of gas turbines increase with increasing turbine rotor inlet temperatures (RIT). Currently, advanced gas turbines operate at turbine RIT around 1700 °C far higher than the yielding point of the blade material temperature about 1200 °C. Therefore, turbine rotor blades need to be cooled by 3–5% of high-pressure compressor air around 700 °C. To design an efficient turbine blade cooling system, it is critical to have a thorough understanding of gas turbine heat transfer characteristics within complex three-dimensional (3D) unsteady high-turbulence flow conditions. Moreover, recent research trend focuses on aircraft gas turbines that operate at even higher RIT up to 2000 °C with a limited amount of cooling air, and land-based power generation gas turbines (including 300–400 MW combined cycles with 60% efficiency) burn alternative syngas fuels with higher heat load to turbine components. It is important to understand gas turbine heat transfer problems with efficient cooling strategies under new harsh working environments. Advanced cooling technology and durable thermal barrier coatings (TBCs) play most critical roles for development of new-generation high-efficiency gas turbines with near-zero emissions for safe and long-life operation. This paper reviews basic gas turbine heat transfer issues with advanced cooling technologies and documents important relevant papers for future research references.
80 citations
TL;DR: This article designs the shroud and turbine shape as well as flange height through an optimization process that seeks to maximize the power while minimizing drag and thrust forces and demonstrates that the resulting optimal designs yield significant improvements in the output power coefficient.
TL;DR: In this article, the characteristics of stainless steel 316L (UNS S31603) parts produced using a selective laser melting machine were investigated based on experimental observations, including geometrical errors, surface microstructures, material compositions, material phases, and residual stresses of the samples produced.
Abstract: Metal additive manufacturing has employed several technologies and processes to advance from rapid prototyping to rapid manufacturing. Additive manufacturing technologies compete with traditional manufacturing methods through their ability to produce complex structures and customized products. This paper aims to study the characteristics of stainless steel 316L (UNS S31603) parts produced using a selective laser melting machine. In the aerospace industry, turbine blades are typically manufactured from nickel-based alloys, titanium alloys, and stainless steels. Several geometries typical of airfoil blades were examined. The main goal is to investigate the material characteristics and surface features of the airfoil blades. The study included the geometrical errors, surface microstructures, material compositions, material phases, and residual stresses of the samples produced. The characteristics of the parts produced were investigated based on experimental observations. The paper also discusses the influence of the part dimension and orientation on the profile error, surface microstructure, and residual stress.
TL;DR: In this article, the effect of volumetric heating on condensing steam flow in the stationary cascade of turbine blades and the losses associated with wetness was analyzed, and the numerical results showed that by applying VOLUMetric heating to the convergent section, the wetness fraction in the turbine blades can be reduced which prevent corrosion losses.
19 Oct 2018
TL;DR: In this article, the authors support the hypothesis that the vast majority of the damage accumulated in the leading edge is imposed during extreme precipitation condition events, which occur during a very small fraction of the turbine's operation life.
Abstract: . Impact fatigue caused by collision with rain droplets, hail stones
and other airborne particles, also known as leading-edge erosion, is a severe
problem for wind turbine blades. Each impact on the leading edge adds an
increment to the accumulated damage in the material. After a number of
impacts the leading-edge material will crack. This paper presents and
supports the hypothesis that the vast majority of the damage accumulated in
the leading edge is imposed at extreme precipitation condition events, which
occur during a very small fraction of the turbine's operation life. By
reducing the tip speed of the blades during these events, the service life of
the leading edges significantly increases from a few years to the full
expected lifetime of the wind turbine. This life extension may cost a
negligible reduction in annual energy production (AEP) in the worst case, and
in the best case a significant increase in AEP will be achieved.
TL;DR: In this article, an overview of the commonly used models, techniques, tools, and experimental approaches applied to increase the efficiency of the wind turbines is presented, with particular emphasis on approaches used to design wind turbine blades both experimental and numerical.
Abstract: Among renewable sources of energy, wind is the most widely used resource due to its commercial acceptance, low cost and ease of operation and maintenance, relatively much less time for its realization from concept till operation, creation of new jobs, and least adverse effect on the environment. The fast technological development in the wind industry and availability of multi megawatt sized horizontal axis wind turbines has further led the promotion of wind power utilization globally. It is a well-known fact that the wind speed increases with height and hence the energy output. However, one cannot go above a certain height due to structural and other issues. Hence other attempts need to be made to increase the efficiency of the wind turbines, maintaining the hub heights to acceptable and controllable limits. The efficiency of the wind turbines or the energy output can be increased by reducing the cut-in-speed and/or the rated-speed by modifying and redesigning the blades. The problem is tackled by identifying the optimization parameters such as annual energy yield, power coefficient, energy cost, blade mass, and blade design constraints such as physical, geometric, and aerodynamic. The present paper provides an overview of the commonly used models, techniques, tools and experimental approaches applied to increase the efficiency of the wind turbines. In the present review work, particular emphasis is made on approaches used to design wind turbine blades both experimental and numerical, methodologies used to study the performance of wind turbines both experimentally and analytically, active and passive techniques used to enhance the power output from wind turbines, reduction in cut-in-speed for improved wind turbine performance, and lastly the research and development work related to new and efficient materials for the wind turbines.
TL;DR: In this article, the authors developed a new class of actuator surface models for turbine blades and nacelle to take into account more geometrical details of turbine blades, and include the effect of turbine naceelle.
Abstract: Actuator line model has been widely employed in wind turbine simulations. However, the standard actuator line model does not include a model for the turbine nacelle which can significantly impact turbine wake characteristics as shown in the literature. Another disadvantage of the standard actuator line model is that more geometrical features of turbine blades cannot be resolved on a finer mesh. To alleviate these disadvantages of the standard model, we develop a new class of actuator surface models for turbine blades and nacelle to take into account more geometrical details of turbine blades and include the effect of turbine nacelle. In the actuator surface model for blade, the aerodynamic forces calculated using the blade element method are distributed from the surface formed by the foil chords at different radial locations. In the actuator surface model for nacelle, the forces are distributed from the actual nacelle surface with the normal force component computed in the same way as in the direct forcing immersed boundary method and the tangential force component computed using a friction coefficient and a reference velocity of the incoming flow. The actuator surface model for nacelle is evaluated by simulating the flow over periodically placed nacelles. Both the actuator surface simulation and the wall-resolved large-eddy simulation are carried out. The comparison shows that the actuator surface model is able to give acceptable results especially at far wake locations on a very coarse mesh. It is noted that although this model is employed for the turbine nacelle in this work, it is also applicable to other bluff bodies. The capability of the actuator surface model in predicting turbine wakes is assessed by simulating the flow over the MEXICO (Model experiments in Controlled Conditions) turbine and a hydrokinetic turbine.
TL;DR: In this article, the authors provide a more comprehensive description of dynamic stall in vertical axis wind turbines, with an emphasis on understanding its parametric dependence and scaling behaviour, and a scaling incorporating the dimensionless pitch rate is proposed.
Abstract: Vertical axis wind turbine blades are subject to rapid, cyclical variations in angle of attack and relative airspeed which can induce dynamic stall. This phenomenon poses an obstacle to the greater implementation of vertical axis wind turbines because dynamic stall can reduce turbine efficiency and induce structural vibrations and noise. This study seeks to provide a more comprehensive description of dynamic stall in vertical axis wind turbines, with an emphasis on understanding its parametric dependence and scaling behaviour. This problem is of practical relevance to vertical axis wind turbine design but the inherent coupling of the pitching and velocity scales in the blade kinematics makes this problem of more broad fundamental interest as well. Experiments are performed using particle image velocimetry in the vicinity of the blades of a straight-bladed gyromill-type vertical axis wind turbine at blade Reynolds numbers of between 50 000 and 140 000, tip speed ratios between to , and dimensionless pitch rates of . The effect of these factors on the evolution, strength and timing of vortex shedding from the turbine blades is determined. It is found that tip speed ratio alone is insufficient to describe the circulation production and vortex shedding behaviour from vertical axis wind turbine blades, and a scaling incorporating the dimensionless pitch rate is proposed.
TL;DR: In this paper, the authors investigated the relationship with aerodynamic properties and vortex shedding from suction surface and wake of wind turbine blade at low Reynolds numbers. And they found that the location and formation of Laminar separation bubbles were affected by variety of both Reynolds number and angle of attack.
TL;DR: In this paper, the authors developed a fully numerical model of wind turbine wakes using CFD by means of a Large Eddy Simulation (LES) model, which is tested against experimental data, showing very good agreement.
TL;DR: Photothermal thermal-wave radar (TWR) nondestructive imaging (NDI) is introduced to IIT, based on cross-correlation (CC) pulse compression and matched filtering and TWR principles are applied to CFRP imaging inspection and diagnosis and TWRI will play an important role in the OCM of the wind turbine blade.
Abstract: Condition monitoring, nondestructive testing, and fault diagnosis are currently considered crucial processes for on-condition maintenance (OCM) to increase the reliability and availability of wind turbines and reduce the wind energy generation cost. Carbon fiber reinforced plastics (CFRPs) have been increasingly used to fabricate wind turbine blades. Delamination-type damage is inevitable during manufacture or in-service of a CFRP blade. This inner (subsurface) flaw, usually difficult to be detected by artificial visual inspection or machine vision based on CCD or CMOS, severely degrades the load-bearing capacity of a blade. Induction infrared thermography (IIT) is an emerging infrared machine vision inspection technology, which has the capability of insight to CFRP based on electromagnetic induction and heat conduction. This paper introduces photothermal thermal-wave radar (TWR) nondestructive imaging (NDI) to IIT, based on cross-correlation (CC) pulse compression and matched filtering and applies TWR principles to CFRP imaging inspection and diagnosis. The experimental studies carried out under the transmission mode have shown that TWR B-scan and phasegram can be used to inspect and diagnose subsurface delaminations in CFRP with improved signal-to-noise ratio (SNR) and shape identification. As a new machine vision inspection method, TWRI will play an important role in the OCM of the wind turbine blade.
TL;DR: Detailed analysis of the best compromise blade design showed that the output of the design methodology is feasible for manufacturing, using for that purpose stochastic multi-objective optimization methods.
17 Jan 2018
TL;DR: In this article, the authors discuss conceptual architectural and structural options for recycling these blades by reusing parts of wind turbine blades in new or retrofitted housing projects, focusing on large-sized FRP pieces that can be salvaged from the turbine blades and can potentially be useful in infrastructure projects where harsh environmental conditions (water and high humidity) exist.
Abstract: The very rapid growth in wind energy technology in the last 15 years has led to a rapid growth in the amount of non-biodegradable, thermosetting fiber reinforced polymer (FRP) composite materials used in wind turbine blades. This paper discusses conceptual architectural and structural options for recycling these blades by reusing parts of wind turbine blades in new or retrofitted housing projects. It focuses on large-sized FRP pieces that can be salvaged from the turbine blades and can potentially be useful in infrastructure projects where harsh environmental conditions (water and high humidity) exist. Since reuse design should be for specific regional locations and architectural characteristics the designs presented in this paper are for the coastal regions of the Yucatan province in Mexico on the Gulf of Mexico where low-quality masonry block informal housing is vulnerable to severe hurricanes and flooding. To demonstrate the concept a prototype 100 m long wind blade model developed by Sandia National Laboratories is used to show how a wind blade can be broken down into parts, thus making it possible to envision architectural applications for the different wind blade segments for housing applications.
TL;DR: In this article, the truncated ribs are employed in internal cooling passages of turbine blades to augment heat transfer with cooling air flowing through the internal ribbed passages, and they generate transverse vortices at the truncation gaps and reduce the recirculating flow behind the ribs.
TL;DR: In this paper, the authors introduce a radica-based approach for wind turbine health monitoring with respect to wind turbine blades, which is challenging due to its large dimensions, as well as the complex and heterogeneous material system.
Abstract: Structural health monitoring of wind turbine blades is challenging due to its large dimensions, as well as the complex and heterogeneous material system. In this article, we will introduce a radica...
TL;DR: In this article, a micro wind turbine blade for low average wind speed regions like the Arabian Peninsula, Jordan Desert and United Arab Emirates is designed and implemented using 3D printer and tested in open air environment to validate the simulation results.
TL;DR: In this paper, the application of natural fibres reinforced polymer composites in wind turbine, requirements to the composites, their properties, constituents, manufacturing technologies, and defects are reviewed; promising future directions of their developments also will be discussed.
TL;DR: In this paper, the wake meandering characteristics of four different wind turbine designs with diameters ranging from a few centimetres (wind tunnel scale) to a hundred metres (utility scale) are investigated using large-eddy simulation with the turbine blades and nacelle parametrised using a new actuator surface model.
Abstract: The wake meandering characteristics of four different wind turbine designs with diameters ranging from a few centimetres (wind tunnel scale) to a hundred metres (utility scale) are investigated using large-eddy simulation with the turbine blades and nacelle parametrised using a new actuator surface model. Different velocity fields and meandering behaviours are observed at near-wake locations. At far-wake locations, on the other hand, the mean velocity deficit profiles begin to collapse when scaled by the centreline velocity deficit based on the incoming wind speed at turbine hub height, suggesting far-wake similarity across scales. The turbine-added turbulence kinetic energy profiles are shown to also nearly collapse with each other in the far wake when normalised using a velocity scale defined by the thrust on the turbine rotor. Moreover, we show that at far-wake locations, the simulated flow fields for all four turbine designs exhibit similar wake meandering characteristics in terms of (1) a Strouhal number independent of rotor designs of different sizes and (2) the distributions of wake meandering wavelengths and amplitudes when normalised by the rotor diameter and a length scale defined by the turbine thrust respectively.
TL;DR: In this article, the authors present an investigation on different methods for the calculation of the angle of attack and the underlying induced velocity on wind turbine blades using data obtained from three-dimensional Computational Fluid Dynamics (CFD).
TL;DR: This study looks at ice detection on wind turbine blades using supervisory control and data acquisition (SCADA) data and thereafter a model based on the random forest classifier is proposed, indicating that it has high accuracy and good generalization ability verified with the data from the China Industrial Big Data Innovation Competition.
Abstract: When wind turbine blades are icing, the output power of a wind turbine tends to reduce, thus informing the selection of two basic variables of wind speed and power. Then other features, such as the degree of power deviation from the power curve fitted by normal sample data, are extracted to build the model based on the random forest classifier with the confusion matrix for result assessment. The model indicates that it has high accuracy and good generalization ability verified with the data from the China Industrial Big Data Innovation Competition. This study looks at ice detection on wind turbine blades using supervisory control and data acquisition (SCADA) data and thereafter a model based on the random forest classifier is proposed. Compared with other classification models, the model based on the random forest classifier is more accurate and more efficient in terms of computing capabilities, making it more suitable for the practical application on ice detection.