scholarly journals Development of an Improved LMD Method for the Low-Frequency Elements Extraction from Turbine Noise Background

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 805
Author(s):  
Lida Liao ◽  
Bin Huang ◽  
Qi Tan ◽  
Kan Huang ◽  
Mei Ma ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Condition Monitoring ◽  
Renewable Energy Sources ◽  
Near Field ◽  
Low Frequency ◽  
Aerodynamic Noise ◽  
Frequency Noise ◽  
Human Society ◽  
Noise Background

Given the prejudicial environmental effects of fossil-fuel based energy production, renewable energy sources can contribute significantly to the sustainability of human society. As a clean, cost effective and inexhaustible renewable energy source, wind energy harvesting has found a wide application to replace conventional energy productions. However, concerns have been raised over the noise generated by turbine operating, which is helpful in fault diagnose but primarily identified for its adverse effects on the local ecosystems. Therefore, noise monitoring and separation is essential in wind turbine deployment. Recent developments in condition monitoring provide a solution for turbine noise and vibration analysis. However, the major component, aerodynamic noise is often distorted in modulation, which consequently affects the condition monitoring. This study is conducted to explore a novel approach to extract low-frequency elements from the aerodynamic noise background, and to improve the efficiency of online monitoring. A framework built on the spline envelope method and improved local mean decomposition has been developed for low-frequency noise extraction, and a case study with real near-field noises generated by a mountain-located wind turbine was employed to validate the proposed approach. Results indicate successful extractions with high resolution and efficiency. Findings of this research are also expected to further support the fault diagnosis and the improvement in condition monitoring of turbine systems.

scholarly journals Holistic simulation of wind turbines with fully aero-elastic and electrical model

2021 ◽  
Author(s):  
Marcus Wiens ◽  
Sebastian Frahm ◽  
Philipp Thomas ◽  
Shoaib Kahn
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Elastic Model ◽  
Electrical Model ◽  
Holistic Model ◽  
Electric System ◽  
Electrical Components

AbstractRequirements for the design of wind turbines advance facing the challenges of a high content of renewable energy sources in the public grid. A high percentage of renewable energy weaken the grid and grid faults become more likely, which add additional loads on the wind turbine. Load calculations with aero-elastic models are standard for the design of wind turbines. Components of the electric system are usually roughly modeled in aero-elastic models and therefore the effect of detailed electrical models on the load calculations is unclear. A holistic wind turbine model is obtained, by combining an aero-elastic model and detailed electrical model into one co-simulation. The holistic model, representing a DFIG turbine is compared to a standard aero-elastic model for load calculations. It is shown that a detailed modelling of the electrical components e.g., generator, converter, and grid, have an influence on the results of load calculations. An analysis of low-voltage-ride-trough events during turbulent wind shows massive increase of loads on the drive train and effects the tower loads. Furthermore, the presented holistic model could be used to investigate different control approaches on the wind turbine dynamics and loads. This approach is applicable to the modelling of a holistic wind park to investigate interaction on the electrical level and simultaneously evaluate the loads on the wind turbine.

Aerodynamic noise from an asymmetric airfoil with perforated extension plates at the trailing edge

2020 ◽  
pp. 1475472X2097838
Author(s):  
CK Sumesh ◽  
TJS Jothi
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Pore Diameter ◽  
Low Frequency ◽  
Aerodynamic Noise ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Trailing Edge ◽  
High Frequency Noise ◽  
Displacement Thickness

This paper investigates the noise emissions from NACA 6412 asymmetric airfoil with different perforated extension plates at the trailing edge. The length of the extension plate is 10 mm, and the pore diameters ( D) considered for the study are in the range of 0.689 to 1.665 mm. The experiments are carried out in the flow velocity ( U∞) range of 20 to 45 m/s, and geometric angles of attack ( αg) values of −10° to +10°. Perforated extensions have an overwhelming response in reducing the low frequency noise (<1.5 kHz), and a reduction of up to 6 dB is observed with an increase in the pore diameter. Contrastingly, the higher frequency noise (>4 kHz) is observed to increase with an increase in the pore diameter. The dominant reduction in the low frequency noise for perforated model airfoils is within the Strouhal number (based on the displacement thickness) of 0.11. The overall sound pressure levels of perforated model airfoils are observed to reduce by a maximum of 2 dB compared to the base airfoil. Finally, by varying the geometric angle of attack from −10° to +10°, the lower frequency noise is seen to increase, while the high frequency noise is observed to decrease.

Wind Turbine Aerodynamic Braking System Analysis Using Chord Wise Spacing

2015 ◽  
Vol 787 ◽  
pp. 217-221 ◽  
Author(s):  
B. Navin Kumar ◽  
K.M. Parammasivam
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Wind Velocity ◽  
Turbine Blade ◽  
Wind Turbines ◽  
Renewable Energy Sources ◽  
Energy Resource ◽  
Braking System ◽  
Extreme Wind ◽  
Wind Potential

Wind energy is one of the most significant renewable energy sources in the world. It is the only promising renewable energy resource that only can satisfy the nation’s energy requirements over the growing demand for electricity. Wind turbines have been installed all over the wind potential areas to generate electricity. The wind turbines are designed to operate at a rated wind velocity. When the wind turbines are exposed to extreme wind velocities such as storm or hurricane, the wind turbine rotates at a higher speed that affects the structural stability of the entire system and may topple the system. Mechanical braking systems and Aerodynamic braking systems have been currently used to control the over speeding of the wind turbine at extreme wind velocity. As a novel approach, it is attempted to control the over speeding of the wind turbine by aerodynamic braking system by providing the chord wise spacing (opening). The turbine blade with chord wise spacing alters the pressure distribution over the turbine blade that brings down the rotational speed of the wind turbine within the allowable limit. In this approach, the over speeding of the wind turbine blades are effectively controlled without affecting the power production. In this paper the different parameters of the chord wise spacing such as position of the spacing, shape of the spacing, width of the spacing and impact on power generation are analyzed and the spacing parameters are experimentally optimized.

Numerical simulation of aeroacoustic noise from landing gear and rectangular cavity

2020 ◽  
Vol 234 (7) ◽  
pp. 1259-1271
Author(s):  
Zhifei Guo ◽  
Peiqing Liu ◽  
Jin Zhang ◽  
Hao Guo
Keyword(s):  
Numerical Simulation ◽  
Low Frequency ◽  
Landing Gear ◽  
Rectangular Cavity ◽  
Cavity Resonance ◽  
Aerodynamic Noise ◽  
Frequency Noise ◽  
Radiation Mechanism ◽  
Ansys Fluent ◽  
Aeroacoustic Noise

This paper is aimed at researching the interaction between aeroacoustic noise radiated from a rectangular cavity (gear bay) and from landing gear. It is a complicated flow-induced noise problem, involving the nonlinear, unsteady evolution of the turbulent structure inside the airflow bypassing the landing gear and the cavity. The generation and radiation mechanism of aeroacoustic noise are also concerned. In fact, it is a problem about the nonlinear interaction between the vortices shedding from the boundary layer of bluff bodies and the cavity-limited shear layer. To simplify this issue, a two-wheel landing gear named LAGOON is chosen as the landing gear model. The unsteady flow field and aerodynamic noise from it is simulated by applying the commercial software ANSYS Fluent. Good agreement is achieved between the numerical simulation and wind tunnel measurements in terms of the aerodynamic and aeroacoustic results. According to the size of LAGOON, a simple rectangular cavity is designed as the landing gear bay. Both the cavity combined with LAGOON and the cavity alone are simulated and compared. The results show that under the blocking effect of a strut, most small pieces of vortices at the trailing edge of the cavity bottom would dissipate rather than move forward along with the backflow, leading to the correlation of cavity resonance being more contrasting and increasing its amplitude. The blockage effect induced by rear wall could also enhance the turbulence kinetic energy at the wake of the strut, thus increasing the low-frequency noise radiated from the strut and cavity.

Aerodynamic Comparison of Straight Edge and Swept Edge Wind Turbine Blade

2008 ◽  
Author(s):  
R. S. Amano ◽  
Ryan J. Malloy
Keyword(s):  
Renewable Energy ◽  
Wind Energy ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Low Cost ◽  
Renewable Energy Sources ◽  
Optimization Technique ◽  
Wind Turbine Blade ◽  
Direct Result ◽  
Low Wind Speed

Recently there has been an increase in the demand for the utilization of clean renewable energy sources. This is a direct result of a rise in oil prices and an increased awareness of human induced climate change. Wind energy has been shown to be one of the most promising sources of renewable energy. With current technology, the low cost of wind energy is competitive with more conventional sources of energy such as coal. This however is only true in areas of high wind density. These areas are not as abundant and therefore the number of profitable sites is limited. This paper explores the possibility increasing the number of profitable sites by optimizing wind turbine blade design for low wind speed areas. The two methods of optimization that are investigated are first, optimizing the angle of attack and chord length for a given airfoil cross section at different positions along the blade and second implementing a swept blade profile. The torque generated from a blade using only the first optimization technique is compared to that generated from a blade using both techniques as well as that generated by NTK500/41 turbine using LM19.1 blades. Performance will be investigated using the CFD solver FLUENT.

Modelling and Control of the Hydraulically Actuated Horizontal Axis Wind Turbine Pitch System

2019 ◽  
Author(s):  
P. Venkaiah ◽  
B. K. Sarkar
Keyword(s):  
Renewable Energy ◽  
Wind Energy ◽  
Wind Turbine ◽  
Wind Power ◽  
Pid Controller ◽  
Renewable Energy Sources ◽  
Horizontal Axis ◽  
Energy Sources ◽  
Horizontal Axis Wind Turbine ◽  
The World

Abstract The advantages of renewable energy sources are available freely in nature, inexhaustible, produce either no or little pollution and low gestation period. Among all renewable energy sources, wind energy has become one of the leading resources for power production in the world as well as in the India. According to WWEA, the wind turbine installation capacity in the world has been reached over 539.291GW by the end of 2017. The entire wind power installed capacity by the end of 2017 covers more than 5% of global demand of electricity. In India, the present wind power installation capacity on October, 2017 was over 32.7GW and wind energy contribution is 55% of the total renewable energy capacity in the country. Inspite of having sharp growth rate in wind in India, only a fraction of wind energy has been tapped until now out of 302 GW wind potential which is available above 100 m height on shore. Practical horizontal axis wind turbine converts kinetic energy in the wind into useful energy by using airfoil blades. Blade element momentum (BEM) theory becomes very popular due to its simplicity in mathematical calculation as well as accuracy. Hydraulic pitch actuation system has certain advantages due to its versatility, ability to produce constant force and torque irrespective of the disturbances outside of the system, ease and accuracy of control, simplicity, safety and economy. In the present study a semi rotary actuator has been utilized for turbine pitch actuation. In order to extract maximum power from available wind, fractional order PID controller (FOPID) has been developed for pitch control of wind turbine rotor blade. The performances of PID as well as FOPID controller have been compared with available wind data. The performance of FOPID controller was satisfactory compare to PID controller.

scholarly journals Research on solar radiation potential as a source of renewable energy in the Motru area

2019 ◽  
Vol 290 ◽  
pp. 11008
Author(s):  
Marin-Silviu Nan ◽  
Alin Sultan ◽  
Danut Grecea ◽  
Cosmin Vitan
Keyword(s):  
Renewable Energy ◽  
Solar Radiation ◽  
Fossil Fuels ◽  
Renewable Energy Sources ◽  
Close Correlation ◽  
Human Society ◽  
Global Level ◽  
Energy Strategy ◽  
The Past ◽  
Energy Modelling

The continuous development of the human society is in a close correlation with the increased consumption of electricity. In the past few years, the thirst for electricity at a global level, has led both to higher levels of pollution and the depletion of fossil fuels. For this reason, the issue of energy efficiency is a priority of energy strategy at national and EU level. In this context, a solution to the above problems is to increase the rate of production of electricity from renewable energy sources. Thus, the paper presents a study of solar radiation as a source of renewable energy, modelling and simulation of photovoltaic systems and validation of data numerical simulations data with the measured data in the Motru area.

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