Blade Structure Research Articles

The mechanical characteristics and cooling performance of a turbine blade with non-homogeneous lattice structure

The turbine blade is working at a high rotation speed and under constant impact from the high-temperature and high-pressure mainstream, causing deformation and a reduction in working efficiency; at the same time, the mainstream temperature at the inlet is increasing to achieve a high heat efficiency. Therefore, there is a high demand for turbine blade cooling technology. In this study, the authors proposed replacing the traditional spoiler with a non-homogeneous lattice structure in the inner cavity of the high-pressure turbine blade. The turbine blade was then simulated and experimend in real-world conditions using numerical simulation software and manufactured actual blades, and the maximum deformation of the turbine blade was measured to assess the impact of the non-homogeneous lattice structure on the blade's strength. The findings are as follows: The maximum deformation of the turbine blade optimized with a non-homogeneous lattice structure is 9.91% less than that of the traditional turbine blade with a spoiler, and its deformation-weight ratio is 11.51% less than the latter; the optimized turbine blade has a large cooling area in the concave surface of the blade, which improves the air film cooling effect, the coverage area of gas film hole outlet flow rate has increased by 12.39%. Finally, the non-homogeneous lattice structure optimizes the inner cavity structure of the turbine blade and is useful for improving the turbine blade's structural design and air film cooling performance.

Glass Fibre Composites Recycling Using the Fluidised Bed: A Comparative Study into the Carbon Footprint in the UK

The UK has no established process for recycling waste glass fibre-reinforced thermosets that are widely used within wind blade structures. Consequently, these materials are typically disposed of in landfills or undergo energy recovery in waste facilities. This study investigates the carbon footprint of the fluidised bed process for recycling glass fibre composite waste, considering the present and future scenarios of composite waste management in the UK. The impact was compared to conventional disposal routes and other prominent recycling technologies, such as cement kiln co-processing and mechanical recycling, by developing energy and material flow models for each waste treatment strategy. Variables, such as the type of waste, the quantity of recycling facilities in the UK, and waste haulage distance, were examined to inform the lowest impact deployment of recycling technologies. Cement kiln co-processing, mechanical, and fluidised bed recycling technologies reduced the global warming potential of processing wind blade waste compared with conventional disposal routes, with impacts of −0.25, −1.25, and −0.57 kg CO2e/kg GRP waste, respectively. Mechanical recycling had the lowest global warming potential resulting from low greenhouse gas emissions associated with the process itself and potentially high offsets by replacing glass fibre in the production of moulding compound. Composite wind turbine blade waste was found to be a particularly promising feedstock for the fluidised bed process due to relatively low resin content diminishing direct greenhouse gas emissions during thermal decomposition, as well as high material recovery offsets due to the high glass fibre content of this waste stream.

Enhancing Epoxy Composite Performance with Carbon Nanofillers: A Solution for Moisture Resistance and Extended Durability in Wind Turbine Blade Structures.

The increasing prominence of glass-fibre-reinforced plastics (GFRPs) in the wind energy industry, due to their exceptional combination of strength, low weight, and resistance to corrosion, makes them an ideal candidate for enhancing the performance and durability of wind turbine blades. The unique properties of GFRPs not only contribute to reduced energy costs through improved aerodynamic efficiency but also extend the operational lifespan of wind turbines. By modifying the epoxy resin with carbon nanofillers, an even higher degree of performance can be achieved. In this work, graphene nanoplatelet (GNP)-enhanced GFRPs are produced through industrial methods (filament winding) and coupons are extracted and tested for their mechanical performance after harsh environmental aging in high temperature and moisture. GNPs enhance the in-plane shear strength of GFRP by 200%, while reducing their water uptake by as much as 40%.

Wakes and secondary structures past stator wheel in test turbine VT-400 observed by PIV

Flow inside the axial test turbine VT-400 is measured by using a standard methodology of Particle Image Velocimetry (PIV). The studied area lies between the stator and rotor wheel in meridional plane. This area covers both: the regular flow near hub and the endwall secondary structures as well. Regular structure of wakes and jets past stator blades is observed in terms of mean velocities and turbulence intensity. The fluctuations are close to isotropy and the energy distribution across length-scales exhibits almost Kolmogorov scaling. Near the hub, we observe secondary vortices. Despite the positive radial ejections in that regions, these secondary vortices drift towards the hub, they dissipate energy and circulation and their core grows in size.

Bilayer fiber membrane electrospun from polylactic acid/alginate/bromelain and polylactic acid for enhancing the functionality of tea bags

Tea bags have been extensively used in the food industry and daily life as an efficient way to pack tea. However, the large pores of the commercial tea bags not only lead to the inner contents of tea bag susceptible to bacteria and moisture but also result in the faster water infusion which is undesired during tea brewing. In this study, the polylactic acid (PLA)-PLA/sodium alginate (SA)/bromelain (BL) bilayer fiber membrane imitating the asymmetric wetting structure of lotus leaf blades was fabricated to avoid the above disadvantages of commercial tea bag. The PLA/SA/BL skin-core nanofiber membrane which imitating the skin-core structure of lotus leaf stems was first prepared as the hydrophilic and support layer, then a hydrophobic PLA layer was deposited on top via electrospinning. The PLA-PLA/SA/BL bilayer fiber membrane had a breaking strength of 5.5 MPa and started to decompose at 260 °C. Using this bilayer membrane, tea bags were designed with a novel structure where the hydrophobic PLA layer was placed in the same direction. The novel structure endow the those tea bags a slow and directional water transfer property. Therefore, the PLA-PLA/SA/BL bilayer fiber membrane has great potential for applications as tea bags.

Genetic algorithm based three-dimensional shape optimization of rotor blade for a Mars multi-rotor aircraft

In the context of Mars exploration, the Mars multi-rotor aircraft plays a significant role, with its blades being the key components for achieving flight. Due to the thin Martian atmosphere, conventional Earth blades struggle to generate the required thrust for comprehensive aerial missions on the Red Planet. To solve these challenging conditions, there arises a compelling need to refine the rotor’s design, optimizing it to provide sufficient thrust while minimizing power consumption. In this research, a novel method is introduced, combining genetic algorithms and computational fluid dynamics simulations. This approach focuses on enhancing the three-dimensional structure of the rotor blade. The results of this research are verified in experiments conducted within the Martain Atmosphere Simulator, where the blade after optimization demonstrated the ability to achieve the same level of thrust while significantly reducing power consumption. Consequently, this study represents a promising avenue for improving the efficiency of Mars multi-rotor aircraft.

Mechanical response analysis of the wide-chord hollow fan blade considering the fluid–structure interaction

The aero-engine wide-chord hollow fan blade with a cavity stiffener structure can effectively reduce the weight and greatly increase the rotational speed. However, during the high-speed rotation process of the hollow fan, there is a strong coupling effect between the solid domain of the blade and the incoming air. This effect leads to a certain deformation of the rotor blade, which has a large impact on the structural strength of the blade. Aiming at the problem of the fluid–structure interaction in its operation, the finite-element method was used to simulate the two-layer structure of the TC4 titanium alloy wide-chord hollow fan blade. The centrifugal force and fluid–structure coupling effect were considered when carrying out the research on the structural mechanical characteristics of the blade. The results show that the maximum equivalent stress of the blade considering the fluid–structure coupling effect is 508 MPa at the rotational speed of 2,900 r/min, which is approximately 18% higher than the maximum stress when only the centrifugal force is considered. This phenomenon indicates that the effect of aerodynamic force on the blade stress cannot be ignored. The stress concentration area of the blade is located in the third stiffener from the leading edge and near the root of the blade, and the aerodynamic force has a more significant effect on the radial stress distribution of the blade. Further analysis of the equivalent stress distribution along the blade tip direction shows a trend of first increasing and then decreasing. The maximum equivalent stress appears at a distance of 30 mm up to the bottom of the stiffener.

Influence of changes in tip structure on wind wheel vibration characteristics under wind wheel-tower coupling

This study conducted modal and vibration-characteristic tests using transient excitation and spectrum analysis methods to find the variation law of vibration characteristics of wind wheels with bifurcated tip structures as compared to wind wheels with unmodified tips when the coupling between a wind wheel and its tower is considered. Additionally, a finite element analysis was used to calculate the mechanical characteristics of wind power manoeuvres. The following are the major results of this study. As compared to the non-trailer state, the coupling action of the wind wheel and the tower reduced the static frequency of the unmodified wind wheel and the bifurcated blade tip structure wind wheel under the trailer state. The static frequency of the bifurcated blade tip structure wind wheel under the coupling action decreases more significantly. Compared with the single wind wheel which is not affected by coupling, the dynamic frequency of the whole machine decreases after being affected by coupling, and the bifurcated blade structure has less influence on the coupling effect. Compared with the non-trailer state, the dynamic frequency curves of the two blade tip structure wind wheels in the trailer state decrease, the speed range in the resonance area is shortened, and the corresponding speed in the resonance area is reduced. The results of this study provide data support and design reference for reliable design of wind turbines.

Anatomy, ploidy level, and essential oil composition of <i>Hyssopus officinalis</i> ʻNikitskiy Beliyʼ <i>in vitro</i> and <i>ex situ</i>

Background. Clonal micropropagation is a biotechnological method for plant multiplication. The existing data on the structure of organs in vitro, genetic stability, and essential oil composition are limited for Hyssopus officinalis L., so this study was aimead at investigating these aspects under a short period of in vitro culturing.Materials and methods. Plants of Hyssopus officinalis ʻNikitskiy Beliyʼ cultivated ex situ, in vitro and ex vitro were analyzed. Conventional methods were applied to study plant anatomy, ploidy level, and relative DNA content, as well as to extract and analyze essential oil. Statistical analysis was performed using the Past 4.03 software.Results. According to the results obtained, with 6-BAP introduced into MS nutrient medium in optimal concentrations (0.3– 0.5 mg/L), the general in vitro structure of leaf blades in the developed microshoots was similar to those in ex situ plants, while the qualitative and quantitative changes observed were induced by the effect of specific culturing conditions and plant rejuvenation. The analysis of the ploidy level and relative DNA content in the nuclei isolated from the leaf tissue cells of the microshoots ex vitro after adaptation revealed no changes compared to the ex situ leaf parameters. The mass fraction of essential oil and its component composition in the mother plants and ex vitro regenerants were similar.Conclusion. Cultivation of Hyssopus officinalis ʻNikitskiy Beliyʼ microshoots on MS nutrient medium with 6-BAP optimal concentrations promotes morphogenesis without significant deviations in the ploidy level, relative DNA content, essential oil yield, or its component composition. The developed protocol for clonal micropropagation of Hyssopus officinalis ʻNikitskiy Beliyʼ provides clones identical to the ex situ plants.

3D multiscale dynamic analysis of offshore wind turbine blade under fully coupled loads

Wind turbine blades are typically sophisticated structures with complex geometry and composite layup. The realistic loads acting on blades serviced in harsh offshore environments are fully coupled dynamic loads involving wind, wave, current, servo-control, gravity and other inertial loads. This work presents an easy-to-implement methodology for the time-domain detailed analysis of three-dimensional (3D) blade structure, by combining fully coupled dynamic simulator and general finite element program. As a practical example subjected to multiple marine environmental loadings, one of the rotating composite blades atop a 5-Megawatt (MW) monopile-supported offshore wind turbine (OWT) in soft clay is used for verifying this method step by step, and the effect of rotation and foundation flexibility on blade behaviours is explored. Good agreement between OpenFAST and proposed method in tip deflections and root reaction loads is visible from validation results, and the recommendations on how to further improve this method in future iterations are made. Subsequently, based on stress-time history of blade composite layups, time-domain 3D multiscale analysis including the failure evaluation for layers in outer shell and shear webs using Tsai-Wu strength criteria, as well as the fatigue damage assessment of carbon spar caps was performed.

An Efficient Computational Analysis and Modelling of Transferred Aerodynamic Loading on Direct-Drive System of 5 MW Wind Turbine and Results Driven Optimisation for a Sustainable Generator Structure

The study presents an efficient computational investigation on the behaviour of the direct-drive system integrated into the offshore 5 MW NREL wind turbine model under demanding aerodynamic loading conditions with the aim of optimising and developing more sustainable key structural components. The research was based on computational simulation packages in order to verify the use of real-world wind data and the loading conditions on the blade structures through aero-elastic simulation studies as well as analyse the behaviour of the drive system. Through the application of validated aerodynamic loading conditions, resulting normal forces on the blades structure were obtained and applied to a dedicated simplified model that was also previously validated to estimate the transferred loads into the powertrain. The adopted methodology allowed for the identification of shaft misalignment induced air gap eccentricity. The impact of shaft deflections on resulting magnetomotive force was considered by making use of the Maxwell stress distribution expression. By taking into account the resulting loading cases on the generator structure, as well as the inherent typical loads generated by the electrical machine, a procedure including structural parametric and topology optimisation was developed and performed, achieving a rotor mass reduction between 8.5 and 9.6% compared to the original model.

Evaluating Mechanical Strength in Vertical-Axis Tidal Turbines: A Comparative Study of Internal Blade Structure and Material Selection through CFD Simulation

Due to the density of water, tidal turbine blades are subject to significantly greater stresses than wind turbine blades. Multiple blade failures occurred during prototype testing as a result of loading conditions and protracted exposure to seawater, which created a severe work environment. The structural integrity of tidal turbine blades is essential for long-term reliability and performance. Numerous investigations into structural performance have been conducted. However, previous research has centred on horizontal-axis tidal turbines, while research on small-scale vertical-axis tidal turbines is limited. This paper aims to compare the Vertical-Axis Tidal Turbine (VATT) structural performance of hollow and solid blade structures in an identical NACA profile using three distinct materials. Finite element analysis (FEA) is employed to construct a model and simulate the mechanical characteristics of VATT blades. The use of static analysis simulation is employed in order to evaluate many parameters, including stress distribution and deflection. Parametric studies are conducted to explore the impact of internal blade structure and materials on mechanical strength. The use of computational fluid dynamics (CFD) simulations is employed for the purpose of analyzing the interaction between blades of vertical axis tidal turbines (VATT) and tidal currents, thereby enabling the assessment of structural loading. According to the simulation results, the hollow profile is subject to significant deflections and stresses. Other data indicates that the utilization of stiffeners in porous structures improves material efficiency and results in lighter blades, although further analysis is needed to investigate fatigue life prediction in optimizing structural design.

Influencing factor and cost optimization for service life of KR impeller

The service life of KR impeller for one steel plant in Southern China is investigated in this paper. It is shown by site investigation and comparison analysis that there is still improving potential for the service life of KR impeller, whose influencing factor includes hot water temperature, rotating speed, stirring duration, refractory of working lining, internal metal core structure, fabricating process, blade structure, hot repairing process and material, desulfurizer composition, interval time between stirrings. If technical optimization is conducted based on the influencing factor, it is predicted that the service life of KR impeller in this plant can be enhanced from 230 heats to 300 or 400 heats, saving 0.4~0.6 RMB/t hot metal.

IoT platform for offshore wind turbine blade structure health monitoring

Wind energy, as renewable energy, is critical in targeting carbon neutrality or net zero emissions in order to address global climate change. Compared with onshore wind turbines, offshore wind turbines enjoy generally higher wind speed, thus producing more electric energy. However, the harsh marine environment, including high winds, wave-induced vibrations and and sea and rain corrosion and erosion, can lead to structural damage, reduced operational efficiency and increased maintenance cost. This paper presents a novel Internet of Things (IoT) platform for structural health monitoring (SHM) of the offshore wind turbine’s key component, the wind turbine blades. This research focuses on developing a comprehensive, real-time monitoring system that utilises advanced sensor networks, edge computing, and advanced predictive algorithms to strengthen on-time maintenance of turbine blades, while avoiding unnecessary and costly regular maintenance.

Digital Strategies to Improve Product Quality and Production Efficiency of Fluorinated Polymers: 2. Heat Removal Performance of Reactor with Internal and External Cooling Systems

This work aims to study the heat transfer performance of a sophisticated industrial suspension polymerization reactor, which is distinguished by its complex blade structure and capability in efficient heat removal,...

Research on the design and application of wind turbine mechanical parts based on parametric modeling

Abstract Based on ANSYS finite element analysis software, a parametric modeling interface for wind turbine blades and pitch bearings is developed using parametric design language. The parametric modeling interface is used to quickly establish a simplified finite element model of the blade and pitch bearing so as to optimize the design of the blade structure, calculate the maximum tensile stress of the bearing and bolt connection, and analyze the relationship between the working stress of the bearing and bolt and the bolt preload. The analysis and calculation results guide the safety and reliability of wind turbine parts design. After analysis, the optimization of blade structure is mainly in the region of leaf root enhancement, the number of layers laid in the cross-section of No. 1-3 has no major modification, the bi-directional cloth in the cross-section of No. 3-6 is increased by 55 layers, 5 layers reduce the cross-section of No. 7-8, and the cross-section of No. 16-23, 1 layer of the bi-directional cloth is increased in order to improve the strength of the tip of the blade and the resistance to bending capacity. The preload force applied to the pitch bearing during the actual installation process is generally 50% to 70% of the yield limit of the bolt material. The pitch bearings have the best load-carrying capacity under ultimate loads, with the ditch curvature radius coefficient and clearance generally around 0.530 and −0.12mm.

Anatomical and morphological features, and productivity of six perennial wheat varieties in the agroecological conditions of the Almaty region, Kazakhstan

Wheat plays a leading role among cultivated crops. However, some anatomical features of the perennial wheat leaf blade structure, cell development, and metameric stem segmentation remain poorly understood. The object of the present study was six varieties of perennial wheat cultivated in the Almaty region of Kazakhstan. During the study, metameric features of the growth and development of the perennial wheat stem internodes were analyzed. The stems consisted of four internodes and very rarely of five. The variety No. 701 had the longest stem (119 ± 4 cm), while the variety Sova had the shortest one (106 ± 4 cm). The variety No. 701 also had the largest leaf blade with a length of 42 cm ± 2 cm and a width of 1.6 ± 0.09 cm, while the variety No. 704 had the smallest leaf blade with a length of 27 ± 1 cm and a width of 1.2 ± 0.06 cm. The average biological productivity of the Sova variety was 10.49 centners per hectare. The varieties No. 703, No. 704, and No. 801 demonstrated high productivity ranging from 26.08 to 28.8 centners per hectare.

Hybrid de-icing method combining electrothermal system and ultrasonic guided waves

A novel hybrid de-icing method combining an electrothermal system and ultrasonic guided waves is proposed for the leading edge structure of wind turbine blades. The adhesion strength between the ice layer and the leading-edge structure is reduced by the electrothermal system. Piezoelectric ultrasonic transducers are used to generate shear stresses to crack and remove ice. The heating resistance wires and transducers are pasted onto the inner surface of the leading-edge structure. The spacing of the resistance wires was calculated by a theoretical thermal model. A temperature recorder was used to measure the temperature changes at different measuring points on the leading-edge surface under electric heating. This study conducted ultrasonic guided waves de-icing, electrothermal de-icing, and combined electrothermal–ultrasonic de-icing experiments in a freezer with an airfoil leading edge model. The results reveal that the combined electrothermal–ultrasonic method is feasible and has great potential for ice shedding acceleration.

Sandwiched film of graphene/silver nanowire conductive layer reinforced by hydroxyethyl cellulose bond layer

Multilayer nanocomposite film made of different materials has multifunctional properties and is applied in the field of flexible electronic devices. Herein, hydroxyethyl cellulose (HEC) and boron nitride nanosheets (BNNS) were used as the matrix and thermal conductivity material of the HEC/BNNS (HB) insulation layer and were combined with conductive blade structure graphene/silver nanowires (GA) film to prepare a three-layer HB/GA20/HB film. Using the high mechanical properties of the HEC based film, the tensile strength of the three-layer film is increased to 22.0 MPa, 633 % higher than that of the pure conductive film. The sensor prepared by multilayer film has good bending sensing performance (1500 cycles) and electromagnetic shielding performance (29.3 dB). The heating temperature of HB/GA20/HB film heater is up to 107.9 °C at 20 V. In the HB/GA20/HB film, the external HB layer provides insulation, thermal conductivity and physical support, and the internal GA layer with good conductive and sensing properties is combined to build a multi-functional sensor, which can be applied as a mobile sensor, heater and electromagnetic shielding material in the flexible wearable field.

Peridynamics-based analysis on fracture behaviors of a turbine blade shroud

Fracture analysis of turbine blades is a critical aspect of turbomachinery design. However, direct numerical analysis of fractures on blades is limited by the complexity of blade structures and discontinuity-induced singularities it meets. Peridynamics (PD) methods are applied to describe discontinuous problems and thus promising for simulating blade fractures. In this paper, a PD method is used to numerically analyze a blade whose shroud is fractured. The established model effectively describes the cracking process and predicts the cracking path. Besides, corrosion-accelerated cracking behaviors are numerically examined, highlighting the ability of PD to solve multi-physical cracking problems in complex structures.