Probabilistic Multibody Modeling of Gearboxes for Wind Turbines

2011 ◽  
Author(s):  
Fisseha M. Alemayehu ◽  
Stephen Ekwaro-Osire
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Loading ◽  
Design Parameters ◽  
Probabilistic Design ◽  
Deterministic Approach ◽  
Early Failure ◽  
Multibody Modeling ◽  
Design Life ◽  
Multibody Dynamic

Gearboxes have been prone to early failure rather than any mechanical part of modern wind turbines, much earlier than their predicted design life. Some studies indicated that gearboxes of wind turbines fail during the first 3 to 5 years of operation of the system as opposed to the total design life of the wind turbine, which usually is 20 years. Consequently, such failures cause the highest down time and extremely expensive replacement activities. Gearboxes are subjected to torsional, bending and axial wind loads which are yet not fully defined. The uncertainty in loading conditions and system design parameters has brought about the importance of considering probabilistic design and modeling approach than the traditional deterministic approach. Accordingly, the motivation of this study is to improve the reliability of gearboxes for wind turbine applications. A probabilistic multibody dynamic modeling of the gearbox, that fully integrates uncertainties in wind loading and design parameters, is sought. This paper presents previous studies and finally proposes the above mentioned approach as a potential way of improving, in general, the reliability of wind energy and, in particular, the gearboxes in wind turbines.

scholarly journals An experimental study of the optimal design parameters of a wind power tower used to improve the performance of vertical axis wind turbines

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879954
Author(s):  
Soo-Yong Cho ◽  
Sang-Kyu Choi ◽  
Jin-Gyun Kim ◽  
Chong-Hyun Cho
Keyword(s):  
Experimental Study ◽  
Optimal Design ◽  
Wind Turbine ◽  
Wind Power ◽  
Wind Turbines ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Design Parameters ◽  
Vertical Axis Wind Turbine ◽  
Vertical Axis Wind Turbines

In order to augment the performance of vertical axis wind turbines, wind power towers have been used because they increase the frontal area. Typically, the wind power tower is installed as a circular column around a vertical axis wind turbine because the vertical axis wind turbine should be operated in an omnidirectional wind. As a result, the performance of the vertical axis wind turbine depends on the design parameters of the wind power tower. An experimental study was conducted in a wind tunnel to investigate the optimal design parameters of the wind power tower. Three different sizes of guide walls were applied to test with various wind power tower design parameters. The tested vertical axis wind turbine consisted of three blades of the NACA0018 profile and its solidity was 0.5. In order to simulate the operation in omnidirectional winds, the wind power tower was fabricated to be rotated. The performance of the vertical axis wind turbine was severely varied depending on the azimuthal location of the wind power tower. Comparison of the performance of the vertical axis wind turbine was performed based on the power coefficient obtained by averaging for the one periodic azimuth angle. The optimal design parameters were estimated using the results obtained under equal experimental conditions. When the non-dimensional inner gap was 0.3, the performance of the vertical axis wind turbine was better than any other gaps.

Probabilistic Performance of Helical Compound Planetary System in Wind Turbine

2015 ◽  
Vol 10 (4) ◽  
Author(s):  
Fisseha M. Alemayehu ◽  
Stephen Ekwaro-Osire
Keyword(s):  
Wind Turbine ◽  
Multibody Systems ◽  
Planetary System ◽  
Design Parameters ◽  
Wind Turbine Gearbox ◽  
New Approach ◽  
Highly Nonlinear ◽  
Multibody Dynamic ◽  
Input Variables ◽  
Maintenance Process

The dynamics of contact, stress and failure analysis of multibody systems is highly nonlinear. Nowadays, several commercial and other analysis software dedicated for this purpose are available. However, these codes do not consider the uncertainty involved in loading, design, and assembly parameters. One of these systems with a combined high nonlinearity and uncertainty of parameters is the gearbox of wind turbines (WTs). Wind turbine gearboxes (WTG) are subjected to variable torsional and nontorsional loads. In addition, the manufacturing and assembly process of these devices results in uncertainty of the design parameters of the system. These gearboxes are reported to fail in their early life of operation, within three to seven years as opposed to the expected twenty years of operation. Their downtime and maintenance process is the most costly of any failure of subassembly of WTs. The objective of this work is to perform a probabilistic multibody dynamic analysis (PMBDA) of a helical compound planetary stage of a selected wind turbine gearbox that considers ten random variables: two loading (the rotor speed, generator side torque), and eight design parameters. The reliability or probabilities of failure of each gear and probabilistic sensitivities of the input variables toward two performance functions have been measured and conclusions have been drawn. The results revealed that PMBDA has demonstrated a new approach of gear system design beyond a traditional deterministic approach. The method demonstrated the components' reliability or probability of failure and sensitivity results that will be used as a tool for designers to make sound decisions.

Design Requirements for Floating Offshore Wind Turbines

2013 ◽  
Author(s):  
Xiaohong Chen ◽  
Qing Yu
Keyword(s):  
Wind Turbine ◽  
Case Studies ◽  
Wind Turbines ◽  
Offshore Wind ◽  
Design Parameters ◽  
Offshore Wind Turbine ◽  
Support Structure ◽  
Offshore Wind Turbines ◽  
Floating Offshore Wind Turbines ◽  
Design Requirements

This paper presents the research in support of the development of design requirements for floating offshore wind turbines (FOWTs). An overview of technical challenges in the design of FOWTs is discussed, followed by a summary of the case studies using representative FOWT concepts. Three design concepts, including a Spar-type, a TLP-type and a Semisubmersible-type floating support structure carrying a 5-MW offshore wind turbine, are selected for the case studies. Both operational and extreme storm conditions on the US Outer Continental Shelf (OCS) are considered. A state-of-the-art simulation technique is employed to perform fully coupled aero-hydro-servo-elastic analysis using the integrated FOWT model. This technique can take into account dynamic interactions among the turbine Rotor-Nacelle Assembly (RNA), turbine control system, floating support structure and stationkeeping system. The relative importance of various design parameters and their impact on the development of design criteria are evaluated through parametric analyses. The paper also introduces the design requirements put forward in the recently published ABS Guide for Building and Classing Floating Offshore Wind Turbine Installations (ABS, 2013).

scholarly journals Effect of Ambient Reynolds Number on Small Wind Turbine Subjected to Low Wind Speed Conditions

2021 ◽  
Vol 12 (2) ◽  
pp. 223-231
Author(s):  
Joel Mbwiga ◽  
Cuthbert Z Kimambo ◽  
Joseph Kihedu
Keyword(s):  
Reynolds Number ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Reynolds Numbers ◽  
Design Parameters ◽  
Power Performance ◽  
Airfoil Surface ◽  
Small Wind Turbine ◽  
Low Wind Speed ◽  
The Difference

Wind flow over the airfoil surface is adversely affected by the differences between the design and ambient values of a dimensionless quantity called Reynolds number. Wind turbine designed for high Reynolds Number shows lower maximum power performance when installed in low-speed wind regime. Tanzanian experience shows that some imported modern wind turbines depict lower power performance compared to the drag-type locally manufactured wind turbines. The most probable reason is the difference between design and local ambient Reynolds numbers. The turbine design parameters have their properties restricted to the range of Reynolds numbers for which the turbine was designed for. When a wind turbine designed for a certain range of Reynolds numbers is made to operate in the Reynolds number out of that range, it behaves differently from the embodied design specifications. The small wind turbine of higher Reynolds number will suffer low lift forces with probably occasional stalls.  

Dynamic Characteristics of Planetary Gears Train of Semi-Direct Drive Wind Turbine

2012 ◽  
Vol 271-272 ◽  
pp. 868-871 ◽  
Author(s):  
Zheng Ming Xiao ◽  
Zhi Hong Yin ◽  
Yu Guo
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Dynamic Characteristics ◽  
Design Parameters ◽  
Support Vector ◽  
Parameter Method ◽  
Direct Drive ◽  
Heavy Load ◽  
Planetary Gears ◽  
Torque Load

The speed increasing gearbox is the key part of the wind turbine, and it requires higher reliability and service life than general mechanical system. The single-stage planetary gears train(PGT) are commonly used in the semi-direct drive wind turbines, which sustain low speed, heavy load, varying speed and varying load. The dynamic characteristics are very complex, due to the frequent disturbance under the random wind and have a greater impact on reliability and stability of wind turbines. In this paper, the torsional dynamic model for PGT of semi-direct drive wind turbine was developed by lumped parameter method. According to the configuration and design parameters of the planetary gears, the natural frequencies are calculated, and the vibration modes are also analyzed. The actual wind speed is simulated by the weight sparse least squares support vector machines (WSLS- SVM), and the input torque load is also obtained. Considering the varying wind load and parameter excitations of system, the dynamic response of the PGT is calculated by numerical method.

Evaluation of Aerodynamic and Seismic Coupling for Wind Turbines Using Finite Element Approach

2013 ◽  
Author(s):  
Mohammad-Amin Asareh ◽  
Jeffery S. Volz
Keyword(s):  
Finite Element ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Large Scale ◽  
Active Regions ◽  
Seismic Loading ◽  
Wind Loading ◽  
Earthquake Excitation ◽  
Element Analysis ◽  
Simulation Codes

The behavior of a wind turbine consists of complex interactions between different components and subsystems. As more large scale wind turbines are constructed in seismically active regions, earthquake excitation makes an even more challenging problem when calculating extreme loads. Turbine specific simulation codes that directly include simulation of aerodynamics and seismic loading often include considerable simplifications to the turbine model that might cause unrealistic scenarios when designing such structures. Turbine related simulation codes are also often unfamiliar for civil engineers. For these reasons, it is desirable to come up with an approach that can handle a more realistic model that can simulate coupling between the influenced loads involved. In this work, the emphasis is put on the response of the tower of a large scale wind turbine subjected to aerodynamic and seismic loading. To capture the inclusive behavior of the structure, finite element analysis was used that consisted of shell elements for the tower, and beam elements for the blades. Various interactions were also used to model the rotation of the rotor during the operation of turbine under wind loading. Results of this approach were compared with previous findings using a selection of ground motions and turbulent wind fields. It is shown that for the turbine operational condition, the presented approach agrees well with the previously verified design codes. The outcome of this approach will provide a better understanding of more detailed structural aspects of wind turbines such as nonlinear behavior and failure criteria that might be considered necessary for a more comprehensive design.

scholarly journals Fabrication and Performance Evaluation of Savonious Vertical Axis Wind Turbine for Uncertain Speed Regions

2017 ◽  
Vol 13 (2) ◽  
Keyword(s):  
Performance Evaluation ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Urban Areas ◽  
Vertical Axis ◽  
Design Parameters ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Vertical Axis Wind Turbines ◽  
And Performance

The consumption of electricity in urban as well as rural is increasing every day and became an essential commodity for household and industrial purposes. Unfortunately the availability of electrical energy in India is not sufficient to the required demand and it is essential to discover and generate energy from non-conventional sources with cheap cost. On the same time it is necessary to reduce the consumption of conventional sources and to save fuel. Among all the renewable resources, wind is one of the best resources available all the time at free of cost. Especially vertical axis wind turbines (VAWT) are self-starting, omni directional. They require no yaw mechanism to continuously orient towards the wind direction and provide a more reliable energy conversion technology, as compared to horizontal axis wind turbine. Particularly savonius vertical axis wind turbines (SVAWT) are suitable and practically possible at low or uncertain wind speed regimes. They can be fitted on rooftops and also suitable for the urban areas where electricity is not available properly. This project deals with the fabrication and performance evaluation of savonius vertical axis wind turbine using two blade rotor. The amount of power developed by the wind turbine is calculated under theoretical and practical conditions and aerodynamics coefficients are also estimated. And various design parameters of savonious rotor are identified and determined.

scholarly journals Simulative Investigation of the Radar Cross Section of Wind Turbines

2019 ◽  
Vol 9 (19) ◽  
pp. 4024 ◽  
Author(s):  
Sebastian Hegler ◽  
Dirk Plettemeier
Keyword(s):  
Power Generation ◽  
Wind Turbine ◽  
Cross Section ◽  
Wind Turbines ◽  
Wind Power Generation ◽  
Rotor Blades ◽  
Design Parameters ◽  
Complex Nature ◽  
Radar Systems ◽  
Turbine Design

Wind-power generation is one of the fundamental sources of renewable energy. However, due to the increasing size of wind turbines, they cause unwanted interference with radar systems for civic protection, especially for on-shore locations. This paper presents parameter studies performed on different wind-turbine models, with a focus on differences of the aerodynamical shape of the rotor blades. Numerical simulation is employed to estimate the influence of different wind-turbine design parameters, with the aim of deriving strategies to minimize wind-turbine influence on radar systems for civic protection. Due to the complex nature of the aerodynamic shape of the blade, a general model cannot be derived from the studies. However, further steps to eventually achieve this goal are outlined.

scholarly journals Blade Design Optimisation for Fixed-Pitch Fixed-Speed Wind Turbines

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Lin Wang ◽  
Xinzi Tang ◽  
Xiongwei Liu
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Wind Turbines ◽  
Wind Turbine Blade ◽  
Design Parameters ◽  
Blade Design ◽  
Small Wind Turbines ◽  
Turbine Blade Design ◽  
Fixed Pitch

Fixed-pitch fixed-speed (FPFS) wind turbines have some distinct advantages over other topologies for small wind turbines, particularly for low wind speed sites. The blade design of FPFS wind turbines is fundamentally different to fixed-pitch variable-speed wind turbine blade design. Theoretically, it is difficult to obtain a global mathematical solution for the blade design optimisation. Through case studies of a given baseline wind turbine and its blade airfoil, this paper aims to demonstrate a practical method for optimum blade design of FPFS small wind turbines. The optimum blade design is based on the aerodynamic characteristics of the airfoil, that is, the lift and drag coefficients, and the annual mean wind speed. The design parameters for the blade optimisation include design wind speed, design tip speed ratio, and design attack angle. A series of design case studies using various design parameters are investigated for the wind turbine blade design. The design outcomes are analyzed and compared to each other against power performance of the rotor and annual energy production. The design outcomes from the limited design cases demonstrate clearly which blade design provides the best performance. This approach can be used for any practice of FPFS wind turbine blade design and refurbishment.

Based on the Research of Wind Turbine Vibration Performance and Aerodynamic Performance

2015 ◽  
Vol 733 ◽  
pp. 493-496 ◽  
Author(s):  
Chun Mei Wu ◽  
Chun Yu Xiong ◽  
Yong Zhao
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Resonance Region ◽  
Economic Benefits ◽  
Energy Utilization ◽  
Design Parameters ◽  
Horizontal Axis Wind Turbine ◽  
Utilization Coefficient ◽  
Vibration Performance

Wind turbines is one of the most important components of the wind turbine, design for wind turbines with good wind turbines is the basis of high wind energy utilization coefficient and large economic benefits. Using the theory of Wilson pneumatic designed 100 W horizontal axis wind turbine, in the process of design and design parameters on the vibration performance correction. Finally on rotor vibration modal experiment and pneumatic external characteristic experiment, the experimental results show that the design of the wind turbine at low wind speed can meet the design of the wind energy utilization coefficient, and the wind machine to avoid the resonance region speed at run time, extend the life of the rotor, so as to reduce the design cost.

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