Design Of Turbine Blades Research Articles

Crack Propagation and Fatigue Life Analysis of Wind Turbine Blades

This dissertation investigates the fatigue and fracture behaviour of wind turbine blades exposed to varying wind speeds and load intensities, aiming to enhance their durability and operational lifespan in sustainable energy systems. The increasing reliance on wind energy underscores the need for durable blades that can withstand cyclic loads and extreme environmental conditions, as fatigue and fracture failures significantly impact maintenance costs and reliability. This research specifically examines fatigue life and fracture initiation at wind speeds of 15 m/s and 60 m/s, analysing the effects of increased load intensities (30 MPa and 62 MPa). Finite Element Analysis (FEA) through ANSYS is employed to model fatigue and fracture dynamics, incorporating fatigue life prediction using S-N curves, stress analysis with von Mises stress, and crack propagation simulation via fracture mechanics principles, such as Paris’ Law. Results reveal a notable reduction in fatigue life with increased loads, evidenced by a drop from 9e09 to 7.9e08 cycles at 15 m/s, with comparable fatigue cycle reductions at 60 m/s. Fracture analysis identifies critical crack initiation points in high-stress areas, and simulations indicate the progressive nature of crack propagation under cyclic loads. These findings underscore the importance of integrating fatigue and fracture assessments in the design and maintenance strategies of wind turbine blades to enhance resilience and support the sustainable advancement of wind energy systems.

Geometric and Flow Characterization of Additively Manufactured Turbine Blades With Drilled Film Cooling Holes

Abstract As designers investigate new cooling technologies to advance future gas turbine engines, manufacturing methods that are fast and accurate are needed. Additive manufacturing facilitates the rapid prototyping of parts at a cost lower than conventional casting but is challenged in accurately reproducing small features such as turbulators, pin fins, and film cooling holes. This study explores the potential application of additive manufacturing and advanced hole drill methods as tools to investigate cooling technologies for future turbine blade designs. Data from computed tomography scans are used to nondestructively evaluate each of the cooling features in the blade. The resulting flow performance of these parts is further related to the manufacturing through benchtop flow testing. Results show that while total blade flow is consistent for all additively manufactured cooled blades, flow through smaller regions of the blades shows variations. Shaped film cooling holes manufactured using a high-speed electrical discharge machining method are within tolerance in the metering section but do not expand at the specified angle in the diffuser even though design tolerances are met. In contrast to high-speed EDM, conventional EDM holes are undersized throughout the length of the hole. Due to the additive manufacturing process, the surface roughness was higher on the additively manufactured parts in the current study than has been previously reported for surface roughness of commonly used cast components. The roughness results show high levels on thin walls, particularly at the trailing edge as well as on downskin surfaces. Internal surface roughness is higher than external roughness at most locations on the blade. The results of this study confirm that additive manufacturing along with advanced hole drilling techniques offers faster development of blade cooling designs.

Fast CFD methodology for accurate prediction of wind turbine airfoil polars by means of Generalized k-omega turbulence model

Abstract Design and optimization of wind turbine blades still relies on 1D numerical codes such as the ones based on the Blade Element Momentum Theory (BEM). These simplified models, require accurate aerodynamics polars as input, for a wide range of Reynolds number conditions, in order to provide reliable predictions. Wind tunnel experimental measurements of lift and drag coefficients is very time consuming and expensive therefore the data available in the scientific literature are generally quite limited. Moreover, the data are often related to few limited operative conditions. On the other hand, the increase of computational power as well as the recent progresses of Computational Fluid Dynamics (CFD) in terms of accuracy and calculation speed have led to an ever wider use of CFD tools for the calculation of the airfoil polars. In this context, the authors developed a fast and accurate CFD methodology based on the use of the recently developed Generalized k-omega (GEKO) RANS turbulence model available in the Ansys Fluent solver. The new procedure to generate a suitable computational domain, the spatial discretization methods as well as Fluent solver settings and GEKO model calibration and optimization are described in detail. The methodology was validated on the basis of experimental data of the widely known S809 wind turbine airfoil, at different Reynolds numbers. Despite the use of a steady RANS turbulence modelling, the proposed CFD methodology demonstrated to accurately predict lift and drag coefficients in fully stalled conditions as well. Moreover, thanks to the automation of the entire CFD process, the methodology allowed to obtain full polars in very short times on a small HPC workstation. Thus, the results of the present work may represent an important step ahead to develop accurate databases of aerodynamic polars by means of a fast and easy but at the same time accurate approach.

A novel generative approach to the parametric design and multi-objective optimization of horizontal axis tidal turbines

As the demand for ocean energy continues to grow, the development of efficient design and optimization methods for tidal current turbines is crucial. Traditional approaches, often based on parameterized models, face challenges in fully capturing the intricate geometric features of turbine blades, limiting the optimization space and affecting convergence efficiency. In response, this study introduces a novel design methodology for horizontal axis tidal turbines (HATTs) using a variational autoencoder generative adversarial network (VAEGAN) model. This approach uses unsupervised learning from a custom dataset to generate new HATT designs, with the VAEGAN model encoding distinct geometric features of turbine blades within a compact latent space, enabling more efficient design space exploration and facilitating the discovery of innovative shapes. Furthermore, in the multi-objective optimization process targeting both hydrodynamic performance and structural strength, the reduced dimensionality of the design variables accelerates convergence while maintaining a broad and meaningful design space. The proposed methodology demonstrates the VAEGAN model's ability to generate diverse and effective turbine blade designs, highlighting its potential as a powerful tool in advancing HATT technology.

Investigating the Performance of Glass Fibre-Reinforced Polymer (GFRP) in the Marine Environment for Tidal Energy: Velocity, Particle Size, Impact Angle and Exposure Time Effects

Tidal energy, with its potential to provide a consistent energy output and reduce carbon emissions, has garnered significant interest. This study, which evaluates the performance of tidal turbine blades in seawater conditions and with sand particles, presents a novel approach. A slurry rig was developed to examine composite materials, and a glass fibre-reinforcement polymeric material was tested over a range of particle sizes, velocities, and impact angles. In addition, this paper used a new test protocol with 14 days (336 h) and 91 days (2184 h) of pre-exposure time of materials before testing. The results, which show significant changes in the erosive mechanisms of GFRP in short- and long-term pre-exposure time as a function of these variables, have profound implications for the design and performance of tidal turbine blades. The study also utilised scanning electron microscopy (SEM), depth profiling analysis, and erosion mapping techniques to compare the erosion behaviours of GFRP. These tools can be used to optimise such materials in tidal turbine conditions.

Aerodynamic performance characteristics of low Re airfoils: A parametric and multi criteria decision study

This research aims at investigating the aerodynamic performance of 51 low Re airfoils and applying a Multi Criteria Decision Making (MCDM) approach for selecting airfoils that align with the specific requirements of small wind turbines (SWTs). The study was carried out by varying the Re from 5 × 104 to 5 × 105; angle of attack (AOA) from −10° to 20°, thickness to chord ratio (0.1–0.9), camber ratio (0.1–0.9), and camber position (10 %–80 %) to evaluate the impact of these parameters on the airfoils’ performance. Furthermore, MCDM approach was applied to identify suitable airfoils optimized for their average lift to drag ratio, stall angle, operating range of AOA, strength, manufacturability, and material cost. The findings showed that of the teste parameters, the AOA and airfoil profile have the most pronounced effects on the airfoil performance. Among the tested airfoils, the E63 provided superior performance at 105 Re with LDR of 76.32, a 37.7 % improvement over that of NACA 4412 which is commonly used for wind turbine blade design. Furthermore, the MCDM results revealed that SG6043, FX63-137, E216 and E62 airfoils were the top-ranked airfoils suitable for SWTs application. These findings can help to produce optimized airfoil designs for increased performance and efficiency of SWTs.

COOLING INJECTION EFFECT ON THE SUCTION SIDE NEAR-TIP REGION OF TURBINE BLADE WITH HIGH-SPEED RELATIVE CASING MOTION

Abstract The high-speed relative casing motion between the casing and the turbine blade tip introduces significant complexities to the flow field near the tip, resulting in alterations to the heat transfer distribution on the suction surface of the blade near the tip, and further influence the arrangement of film cooling arrangements. However, due to the challenges associated with measuring heat transfer, the influence of cooling injection on the near-tip region of the suction side under high-speed relative casing motion still remains uncertain. This study aims to address this knowledge gap by conducting experiments on a high-speed disk rotor experimental rig. The heat transfer coefficient and cooling effectiveness are investigated for different cooling hole arrangements. Additionally, based on Computational Fluid Dynamic (CFD) method, the interaction mechanism of cooling injections under high-speed relative casing movement is comprehensively discussed. It is observed that the cooling effect, which would be effective under stationary conditions, is greatly diminished or even rendered ineffective when subjected to high-speed relative casing conditions. Furthermore, arranging the cooling holes at the location where the interaction between the Over-Tip-Leakage flow and the passage flow occurs would be an effective approach to enhance the cooling performance on blade near-tip suction side. The effect of different relative casing speed on suction side near-tip region cooling injection performances are also numerically investigated. These findings contribute to a better understanding of the considerations involved in the film cooling design of turbine blades.

Design and analysis of hundred-meter wind turbine blade trailing edge based on finite element method (FEM)

Abstract The trailing edge region of composite wind turbine blades usually has a large deformation under wind load and the accidents caused by the damage of blade trailing edge accounts for a large proportion among blade accidents. With the development of large blade size, higher requirements are put forward for the stability of wind turbine blade trailing edge. Therefore, the trailing edge region is critical in the design of blade. A detailed study of the design and analysis for wind turbine blade trailing edge region was carried out in which the structure stability was regarded as the key. The influence of auxiliary spar cap and auxiliary spar web on the stiffness distribution and stability of the trailing edge were studied based on focus and finite element method (FEM). The respiratory effect of different structures due to deformation were analyzed and compared. The results showed that the structure of the auxiliary spar cap and auxiliary spar web can significantly increase stiffness, stability and decrease respiratory deformation at the trailing edge of blade compared to the traditional three webs structure. The structure of auxiliary spar and auxiliary spar web is the best design scheme for hundred-meter composite blade trailing edge.

Investigation of Vertical-axis Tidal Turbine Mechanical Strength using FSI Analysis based on Blade Profile

Abstract Tidal energy, as a renewable energy source harnessed from the ocean, holds substantial promise owing to its heightened energy density, reliability, and longevity. An investigation encompassing the deployment of tidal stream electricity from 2003 through August 2020 revealed that blade malfunction was identified as the primary reason for system failures, with generator and monitoring system failures occurring subsequently. The majority of the research that has been done on the design of vertical-axis tidal turbine blades has focused on how well the blade performs in terms of power output without taking into account the generation of mechanical force. This force can potentially shorten the blade’s lifetime when implemented in a real-world scenario. By modelling a steady-state fluid-structure interaction (FSI) configuration, this study examines how the shape of the turbine blades affects the amount of mechanical force they generate, particularly in vertical-axis tidal turbines. The type of blade profile is the variable under consideration, and the stress levels experienced by a structure are influenced by the type of blade profile used. When comparing symmetrical and asymmetrical NACA straight blade types under similar climatic conditions, it has been found that the blade profile plays a significant role. Asymmetrical blade profiles, in particular, generate a higher lift force compared to symmetrical ones, thereby affecting stress levels more noticeably.

Bend-twist adaptive control for flexible wind turbine blades: Principles and experimental validation

This study proposes a new methodology for optimizing the power curve of a wind turbine at low wind speeds. The principles of bend-twist coupling and the mechanism of energy exchange between the structure and inflow are analyzed. For the blade’s geometric nonlinearity, the virtual displacements and strain fields are described using the Green-Lagrange strain theorem, retaining third-order terms in the energy expressions. The equations of motion are derived using Hamilton’s principle. The bend-twist coupling effects and large deformations of the blade are analyzed using the Updated Lagrange method. Notably, the angle of attack for a single blade section is influenced by bend-twist deformation, causing variations in the rotor’s maximum power coefficient from its optimal value. Additionally, the projection length of the blade, influenced by centrifugal forces, also affects the bend-twist deformation. Based on these findings, an aero-elastic coupling control strategy, termed “Bend-twist Adaptive Control”, is proposed and validated through experiments. The results demonstrate that the proposed control strategy could increase annual power production by 2.3 %. These conclusions offer a promising outlook for future wind turbine blade design and power optimization.

Experimental study and life prediction for aero-engine turbine blade considering creep-fatigue interaction effect

As an important failure form of the turbine blade, creep-fatigue interaction damage affects the safe operation and maintenance strategy of aero-engine, and has been the focus of scientific research and the academic community. Firstly, based on the Kachanov-Rabotnov-Lemaitre continuum damage mechanics theory and the nonlinear symmetry of creep damage and fatigue damage, a creep-fatigue life prediction model is constructed considering the interaction effect in this paper. Then, based on the thermal-fluid–solid multi-physical field coupling numerical simulation of the turbine blade, the equivalent method of creep-fatigue load spectrum was explored according to the equal damage criterion and linear damage rule, and the creep-fatigue interaction test of smooth samples of the blade material was conducted to analyze the creep-fatigue fracture morphology. Finally, the stress term in the creep-fatigue life prediction model of blade material is modified by the correction factor α, and the modified creep-fatigue life prediction model of the turbine blade is constructed considering the interaction effect. The results show that the modified creep-fatigue life prediction model considering the interaction effect has a high life prediction ability with an error of 3.9%. The above research has important scientific research value for the life extension design of turbine blades and the improvement of aero-engine maintenance strategy.

A comprehensive study of recent studies on the efficiency of axial flow turbines with an investigation on blade profile modifications in stator and rotor assemblies

Axial flow turbines are crucial in energy production and propulsion across diverse applications. As global energy needs rise, optimizing turbine efficiency is paramount. This review delves into the aerodynamic design of turbine blades, specifically examining blade profile modifications in both stator and rotor assemblies of state-of-the-art models proposed in the studies from 2019 to 2024. The focus is on mitigating performance discrepancies between idealized simulations and real-world applications, which present significant challenges such as inconsistencies in computational fluid dynamics (CFD) predictions and manufacturing constraints. Key findings from this review highlight a potential efficiency gain of 1%–3% through optimal blade designs that reduce incidence losses, secondary flows, and tip vortex formation. Advanced modeling techniques, including high-fidelity, multi-objective optimization with machine learning, are evolving to better predict and enhance turbine performance. However, gaps remain in system-level integration and the limited experimental data restricts comprehensive validation of these new designs. The insights from this review will aid the research community by identifying critical areas for future investigation, such as integrating blade aerodynamics with heat transfer and structural mechanics. Further, it emphasizes the need for exploring combinations of passive and active flow control strategies to fully harness the benefits of blade profile enhancements. These efforts are crucial for achieving substantial improvements in turbine efficiency, which are essential for meeting the growing demands for sustainable and efficient energy production.

Experimental and numerical study on integrated film cooling of turbine endwall by upstream slot leakage and blade showerhead jets

Prior emphasis on isolated turbine cooling structures resulted in low coolant utilization, but research on coolant interactions of different components remains scarce. This paper experimentally and numerically investigates the interaction effects between two inherent coolant jets from the endwall slot and blade showerhead. Their combined effect on endwall aero-thermal performance is measured by an Infrared camera, and the secondary flows under coolant mix are analyzed. The results show that blade showerhead coolant can play secondary cooling effects on endwall through reattachment, and it can also influence the endwall cooling distribution through altering the secondary flow development near leading edge. At high slot mass flow ratio (MFR) of 2.3%, the showerhead jets lead to secondary endwall cooling effectiveness of up to 0.2 in pressure side junction and suction side hot ring when showerhead MFR is 0.36%. With a further increase in the showerhead coolant MFR to 0.77%, the showerhead jets push the horseshoe vortex to reattach on pressure side endwall, and thus a high cooling region is formed on pressure side endwall near the slot edge. At low slot MFR of 1.5%, the slot leakage mainly covers the suction side endwall with a large hot ring. The reattachment of showerhead coolant on endwall is weak when the showerhead MFR is 0.36%. When showerhead MFR increases to 0.77%, the showerhead coolant has an ideal secondary cooling effect on endwall suction side hot ring, pressure side upstream part endwall, and pressure side junction. The heat transfer coefficient within the pressure side hot ring and pressure side junction both reaches 400. This paper can guide the joint design of turbine blade and endwall cooling layouts.

Industrial Metaverse: A proactive human-robot collaboration perspective

Human-centricity, sustainability, and resilience are becoming core values in modern manufacturing, with human–robot collaboration (HRC) in high demand for flexible automation. However, human–robotic swarms are typically designed to target one specific procedure and cannot fully share their autonomy. The Metaverse, characterized by socialized avatars in a virtual-physical fused world, holds the promise of Proactive HRC. In line with this evolutionary roadmap, this paper presents a futuristic perspective on the industrial Metaverse for Proactive HRC and identifies its six embodiments. A representative universe that supports online and offline human users/operators in the design, machining, and maintenance of aeroengine turbine blades is introduced to spark and accelerate future implementation of the industrial Metaverse for Proactive HRC. The current challenges and future opportunities of this paradigm are also highlighted. It is hoped that this work can attract further investigation and discussions, providing useful insights to both academic and industrial practitioners in smart manufacturing.

Can bird, cetacean, and insect inspired techniques improve the aerodynamic performance of DU 06 W 200 airfoil applied in vertical axis wind turbines?

ABSTRACT To achieve a better aerodynamic performance of wind turbines, the selection of a proper airfoil plays a crucial role. Generally, aviation airfoils (such as the NACA series) were widely used in the design of wind turbine blades due to their aerodynamic characteristics. However, several studies have shown that there are a number of defects in the application of aviation airfoils for blade design, such as poor stall characteristics or incompatible performance at different Reynolds numbers. The aerodynamic performance and lift force of newly developed airfoils inspired by cetaceans, birds, and insects were numerically investigated by CFD in the range of Reynolds number of 1.2 × 105 to 1.7 × 105 and a range of angles of attack (from 0° to 25°). ANSYS Fluent and the Shear Stress Transport (SST) k-ω turbulence models were selected to analyse the pressure and velocity distributions around the airfoils. In addition, the aerodynamic efficiency was calculated for all different cases. For verification and comparison, DU 06-W-200 airfoil was also simulated under the same operating conditions. Results revealed that several of these new bio-inspired designs can increase the aerodynamic performance of the DU 06-W-200 airfoil by up to 24.7%, with the bird-inspired airfoils presenting the best performance among all designs, and the best options for the design of vertical axis wind turbine (VAWT) blades.

In-Depth Study on the Application of a Graphene Platelet-reinforced Composite to Wind Turbine Blades.

Graphene platelets (GPLs) are gaining popularity across various sectors for enhancing the strength and reducing the weight of structures, thanks to their outstanding mechanical characteristics and low manufacturing cost. Among many engineering structures, wind turbine blades are a prime candidate for the integration of such advanced nanofillers, offering potential improvements in the efficiency of energy generation and reductions in the construction costs of support structures. This study aims to explore the potential of GPLs for use in wind turbine blades by evaluating their impact on material costs as well as mechanical performance. A series of finite element analyses (FEAs) were conducted to examine the variations of mechanical performances-specifically, free vibration, bending, torsional deformation, and weight reductions relative to conventional fiberglass-based blades. Details of computational modeling techniques are presented in this paper. Based on the outcomes of these analyses, the mechanical performances of GPL-reinforced wind turbine blades are reviewed along with a cost-benefit analysis, exemplified through a 5MW-class wind turbine blade. The findings affirm the practicality and benefits of employing GPLs in the design and fabrication of wind turbine blades.

The rapid improvement method of fatigue life reliability for single-crystal aeroengine turbine blades: Casting orientation design technology

The uncertainty in the casting orientation of single-crystal aeroengine turbine blades is an intractable engineering problem, and breaking through the crystal orientation design technology is vitally important to enhance the fatigue lifetime reliability of the blade. In this paper, a three-dimensional decoupling model for casting orientation is established according to the crystallographic characteristics of single-crystal blade, and the distribution information and statistical features of the orientation deviation angle of single-crystal turbine blades are obtained for the first time according to this decoupling model. Subsequently, the orientation-dependent models and generalized regression neural networks (GRNNs) analysis system of reliability are established, and the analysis of fatigue life response for single-crystal blades in four quadrants is carried out based on the neural network analysis system. Finally, three orientation design schemes are developed, and the improvement effect of each scheme on lifetime reliability are investigated. For the secondary orientation design scheme, the lifetime reliability is improved from 62 % to more than 95 % at the design life of 15,000 cycles; For the integrated orientation design scheme, the life reliability is improved from 50 % to more than 95 % at the design life of 20,000 cycles. The results show that the orientation design can effectively improve the fatigue life reliability of the product, especially in the long-life design interval of 10,000 to 20,000 cycles. Therefore, the orientation design should be highly emphasized in the design of single-crystal turbine blades for aeroengine.

Comparison of different cross-sectional approaches for the structural design and optimization of composite wind turbine blades based on beam models

Abstract. During the preliminary design phase of wind turbine blades, the evaluation of many design candidates in a short period of time plays an important role. Computationally efficient methods for the structural analysis that correctly predict stiffness matrix entries for beam models including the (bend–twist) coupling terms are thus needed. The present paper provides an extended overview of available approaches and shows their abilities to fulfill the requirements for the composite design of rotor blades with respect to accuracy and computational efficiency. Three cross-sectional theories are selected and implemented to compare the prediction quality of the cross-sectional coupling stiffness terms and the stress distribution based on different multi-cell test cross-sections. The cross-sectional results are compared with the 2D finite element code BECAS and are discussed in the context of accuracy and computational efficiency. The analytical solution performing best shows very small deviations in the stiffness matrix entries compared to BECAS (below 1 % in the majority of test cases). It achieved a better resolution of the stress distribution and a computation time that is more than an order of magnitude smaller using the same spatial discretization. The deviations of the stress distributions are below 10 % for most test cases. The analytical solution can thus be rated as a feasible approach for a beam-based pre-design of wind turbine rotor blades.

Multi-Objective Optimization Design of Dynamic Performance of Hydrofoil with Gurney Flap

The horizontal axis tidal turbine, as a crucial device for capturing tidal energy, has gained significant attention because it has better energy efficiency performance. Enhancing the performance of foils, a vital part of tidal turbine blades, can significantly improve tidal turbine performance. Among numerous methods to enhance the foil performance, the Gurney flap has gained significant attention due to its avoidance of complex structural design. Currently, there is limited research on optimizing the design of Gurney flaps while considering the dynamic performance of foils. In this study, the S809 foil with a blade cross-section was selected as the research subject, a multi-objective optimization design platform was created by integrating a multi-objective optimization algorithm with Computational Fluid Dy-namics (CFD) numerical simulation techniques. The objective of this platform is to enhance the dynamic performance of the hydrofoil by optimizing the geometric structure of the Gurney flap. The improvement of dynamic lift and the size of the dynamic stall hysteresis loop are used as objective variables in this study to evaluate the hydrofoil’s dynamic performance. The optimal Latin hypercube design method is used in the optimization process to choose sample locations, and the Kriging approximation model is used to determine the relationship between the design variables and the objective variables. Meanwhile, the Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) is used to create a multi-objective optimization platform for solving the optimization problem, and the optimized results are validated using CFD. Comparative validation results show that quantifying the dynamic performance during hydrofoil pitching oscillation and using the optimal Latin hypercube design method and Kriging approximation model for optimizing the Gurney flap structure is rational and accurate. This study explores the mechanism of the Gurney flap through in-depth CFD numerical simulations and finds that the Gurney flap affects the flow characteristics at the hydrofoil’s trailing edge, thereby influencing the performance. It increases the pressure difference between the pressure and suction surfaces, thus enhancing the hydrofoil’s lift. Finally, this article provides three recommended parameters to improve the dynamic performance of the hydrofoil. This research can serve as a reference for the application of Gurney flaps in tidal turbine blade design.

Optimized design of tidal current turbine blade at low current rate

Optimized design of tidal current turbine blade at low current rate