scholarly journals CFD analysis of operational flow nature of a wind turbine model using environmental wind data from Nigerian Defence Academy (NDA)

2021 ◽  
Vol 40 (4) ◽  
pp. 623-630
Author(s):  
M. Samuel ◽  
S.U. Muhammad ◽  
W.C. Solomon ◽  
G.C. Japheth
Keyword(s):  
Wind Speed ◽  
Turbulent Flow ◽  
Wind Turbine ◽  
Flow Analysis ◽  
Cfd Analysis ◽  
Model Design ◽  
Wind Speeds ◽  
Operational Flow ◽  
Turbine Model

A wind turbine is a machine which converts the power in the wind into electricity. It operates under varying wind speeds depending on the environmental wind conditions. In this paper, we have presented the operational flow analysis of a proposed wind turbine model in Nigerian Defence Academy (NDA) Kaduna. The case study is for 5.6m/s, 7.5m/s and 9.5m/s wind speed. The model design and assembly of the components were done with the help of SolidWorks 2018 and the operational flow analysis done with ANSYS 15.0. The result showed that the flow nature of the turbine model grew from laminar flow to turbulent flow increasingly with the environmental wind speed. The flow nature remained laminar from 0.0356 to 1780 Reynolds at 5.6m/s. At 7.5m/s wind speed, from laminar 0.403 Reynolds to turbulent 4290 Reynolds and at 9.5m/s, from laminar 0.381 Reynolds to turbulent 4900 Reynolds. High turbulent flow and mass imbalance nature depicts that phenomenon like wake and vibration of the system occurred.

SHAPING OF AN AUTONOMOUS POWER SYSTEM FOR GUARANTEED POWER SUPPLY WITH THE PREDOMINANCE WIND ENERGY

2018 ◽  
pp. 28-50
Author(s):  
S. G. Ignatiev ◽  
S. V. Kiseleva
Keyword(s):  
Energy Storage ◽  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Demand ◽  
Diesel Generator ◽  
Average Wind Speed ◽  
Wind Speeds ◽  
Average Wind

Optimization of the autonomous wind-diesel plants composition and of their power for guaranteed energy supply, despite the long history of research, the diversity of approaches and methods, is an urgent problem. In this paper, a detailed analysis of the wind energy characteristics is proposed to shape an autonomous power system for a guaranteed power supply with predominance wind energy. The analysis was carried out on the basis of wind speed measurements in the south of the European part of Russia during 8 months at different heights with a discreteness of 10 minutes. As a result, we have obtained a sequence of average daily wind speeds and the sequences constructed by arbitrary variations in the distribution of average daily wind speeds in this interval. These sequences have been used to calculate energy balances in systems (wind turbines + diesel generator + consumer with constant and limited daily energy demand) and (wind turbines + diesel generator + consumer with constant and limited daily energy demand + energy storage). In order to maximize the use of wind energy, the wind turbine integrally for the period in question is assumed to produce the required amount of energy. For the generality of consideration, we have introduced the relative values of the required energy, relative energy produced by the wind turbine and the diesel generator and relative storage capacity by normalizing them to the swept area of the wind wheel. The paper shows the effect of the average wind speed over the period on the energy characteristics of the system (wind turbine + diesel generator + consumer). It was found that the wind turbine energy produced, wind turbine energy used by the consumer, fuel consumption, and fuel economy depend (close to cubic dependence) upon the specified average wind speed. It was found that, for the same system with a limited amount of required energy and high average wind speed over the period, the wind turbines with lower generator power and smaller wind wheel radius use wind energy more efficiently than the wind turbines with higher generator power and larger wind wheel radius at less average wind speed. For the system (wind turbine + diesel generator + energy storage + consumer) with increasing average speed for a given amount of energy required, which in general is covered by the energy production of wind turbines for the period, the maximum size capacity of the storage device decreases. With decreasing the energy storage capacity, the influence of the random nature of the change in wind speed decreases, and at some values of the relative capacity, it can be neglected.

Numerical Studies of the Effects of Active and Passive Circulation Enhancement Concepts on Wind Turbine Performance

2006 ◽  
Vol 128 (4) ◽  
pp. 432-444 ◽  
Author(s):  
Chanin Tongchitpakdee ◽  
Sarun Benjanirat ◽  
Lakshmi N. Sankar
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Turbine Rotor ◽  
Horizontal Axis Wind Turbine ◽  
Trailing Edge ◽  
Low Wind Speed ◽  
Gurney Flap ◽  
Coanda Jet

The aerodynamic performance of a wind turbine rotor equipped with circulation enhancement technology (trailing-edge blowing or Gurney flaps) is investigated using a three-dimensional unsteady viscous flow analysis. The National Renewable Energy Laboratory Phase VI horizontal axis wind turbine is chosen as the baseline configuration. Experimental data for the baseline case is used to validate the flow solver, prior to its use in exploring these concepts. Calculations have been performed for axial and yawed flow at several wind conditions. Results presented include radial distribution of the normal and tangential forces, shaft torque, root flap moment, and surface pressure distributions at selected radial locations. At low wind speed (7m∕s) where the flow is fully attached, it is shown that a Coanda jet at the trailing edge of the rotor blade is effective at increasing circulation resulting in an increase of lift and the chordwise thrust force. This leads to an increased amount of net power generation compared to the baseline configuration for moderate blowing coefficients (Cμ⩽0.075). A passive Gurney flap was found to increase the bound circulation and produce increased power in a manner similar to Coanda jet. At high wind speed (15m∕s) where the flow is separated, both the Coanda jet and Gurney flap become ineffective. The effects of these two concepts on the root bending moments have also been studied.

scholarly journals Numerical Simulation of the Aeroelastic Response of Wind Turbines in Typhoons Based on the Mesoscale WRF Model

2019 ◽  
Vol 12 (1) ◽  
pp. 34
Author(s):  
Long Wang ◽  
Cheng Chen ◽  
Tongguang Wang ◽  
Weibin Wang
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Direction ◽  
Flow Direction ◽  
Wrf Model ◽  
Normal Operation ◽  
Average Wind Speed ◽  
Aeroelastic Response ◽  
Response Characteristics ◽  
Wind Speeds

A new simulation method for the aeroelastic response of wind turbines under typhoons is proposed. The mesoscale Weather Research and Forecasting (WRF) model was used to simulate a typhoon’s average wind speed field. The measured power spectrum and inverse Fourier transform method were coupled to simulate the pulsating wind speed field. Based on the modal method and beam theory, the wind turbine model was constructed, and the GH-BLADED commercial software package was used to calculate the aerodynamic load and aeroelastic response. The proposed method was applied to assess aeroelastic response characteristics of a commercial 6 MW offshore wind turbine under different wind speeds and direction variation patterns for the case study of typhoon Hagupit (2008), with a maximal wind speed of 230 km/h. The simulation results show that the typhoon’s average wind speed field and turbulence characteristics simulated by the proposed method are in good agreement with the measured values: Their difference in the main flow direction is only 1.7%. The scope of the wind turbine blade in the typhoon is significantly larger than under normal wind, while that under normal operation is higher than that under shutdown, even at low wind speeds. In addition, an abrupt change in wind direction has a significant impact on wind turbine response characteristics. Under normal operation, a sharp variation of the wind direction by 90 degrees in 6 s increases the wind turbine (WT) vibration scope by 27.9% in comparison with the case of permanent wind direction. In particular, the maximum deflection of the wind tower tip in the incoming flow direction reaches 28.4 m, which significantly exceeds the design standard safety threshold.

scholarly journals Analysis of the Patent of a Protective Cover for Vertical-Axis Wind Turbines (VAWTs): Simulations of Wind Flow

2020 ◽  
Vol 12 (18) ◽  
pp. 7818
Author(s):  
Jose Alberto Moleón Baca ◽  
Antonio Jesús Expósito González ◽  
Candido Gutiérrez Montes
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
High Speed ◽  
Experimental Tests ◽  
Weather Conditions ◽  
Vertical Axis ◽  
Good Alternative ◽  
Wind Speeds ◽  
Vertical Axis Wind Turbines

This paper presents a numerical and experimental analysis of the patent of a device to be used in vertical-axis wind turbines (VAWTs) under extreme wind conditions. The device consists of two hemispheres interconnected by a set of conveniently implemented variable section ducts through which the wind circulates to the blades. Furthermore, the design of the cross-section of the ducts allows the control of the wind speed inside the device. These ducts are intended to work as diffusers or nozzles, depending on the needs of the installation site. Simulations were performed for the case of high-speed external wind, for which the ducts act as diffusers to reduce wind speed and maintain a well-functioning internal turbine. Four different patent designs were analyzed, focusing on turbine performance and generated power. The results indicate that the patent allows the generation of electric power for a greater range of wind speeds than with a normal wind turbine. The results support that this patent may be a good alternative for wind power generation in geographic areas with extreme weather conditions or with maintained or strong gusty wind. Experimental tests were carried out on the movement of the blades using the available model. Finally, the power curve of the model of this wind turbine was obtained.

scholarly journals Study on the Influence of Baseline Control System on the Fragility of Large-Scale Wind Turbine considering Seismic-Aerodynamic Combination

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Chenyang Yuan ◽  
Jing Li ◽  
Jianyun Chen ◽  
Qiang Xu ◽  
Yunfei Xie
Keyword(s):  
Control System ◽  
Wind Speed ◽  
Wind Turbine ◽  
Large Scale ◽  
Fragility Curves ◽  
Operating Conditions ◽  
Ground Acceleration ◽  
Wind Speeds ◽  
Speed Range ◽  
Wind Actions

The purpose of this paper is to explore the effect of the baseline control system (BCS) on the fragility of large-scale wind turbine when seismic and wind actions are considered simultaneously. The BCS is used to control the power output by regulating rotor speed and blade-pitch angle in real time. In this study, the fragility analysis was performed and compared between two models using different peak ground acceleration, wind speeds, and specified critical levels. The fragility curves with different wind conditions are obtained using the multiple stripe analysis (MSA) method. The calculation results show that the probability of exceedance specified critical level increases as the wind speed increases in model 1 without considering BCS, while does not have an obvious change in the below-rated wind speed range and has a significant decrease in the above-rated wind speed range in model 2 with considering BCS. The comparison depicts that if the BCS is neglected, the fragility of large-scale wind turbine will be underestimated in around the cut-in wind speed range and overestimated in the over-rated wind speed range. It is concluded that the BCS has a great effect on the fragility especially within the operating conditions when the rated wind speed is exceeded, and it should be considered when estimating the fragility of wind turbine subjected to the interaction of seismic and aerodynamic loads.

Wind-Turbine Model for System Simulations Near Cut-In Wind Speed

2007 ◽  
Vol 22 (2) ◽  
pp. 414-420 ◽  
Author(s):  
Christian Eisenhut ◽  
Florian Krug ◽  
Christian Schram ◽  
Bernd Klckl
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Turbine Model

Three-Dimensional Unsteady Simulation in a Water Turbine

2013 ◽  
Vol 655-657 ◽  
pp. 227-230
Author(s):  
Ying Hu ◽  
Kun Wang
Keyword(s):  
Turbulent Flow ◽  
Transient Flow ◽  
Flow Analysis ◽  
Flow Fields ◽  
Francis Turbine ◽  
Optimum Operating ◽  
Time Step ◽  
Optimum Operating Condition ◽  
Water Turbine ◽  
Turbine Model

This paper introduces the 3D numerical simulation of unsteady turbulent flow in the entire flow passage of a water turbine model with CFD technology. A new and available method for the design of a Francis turbine has been explored. The boundary conditions have been implemented based on the 3D averaged N-S equations. The governing equations are discreted on space by the finite volume method and on time step by the finite difference method. The 3D unsteady turbulent flow in an entire Francis turbine model is calculated successfully using the CFX-TASCflow software and RNG k-εturbulence model. Transient flow fields are simulated in the spiral case, the distributor, the runner and the draft tube. It is presented in this paper that the computer simulation of the flow fields in components of the Francis turbine at the optimum operating condition. Meanwhile, the velocity and pressure at any points in the flow fields can be obtained so as to provide the great value on the performance prediction. According to the simulating results, the flow analysis and the design experience, the design of components in a Francis turbine model can be improved and optimized. In this way, designers may decrease numbers of test and shorten the period for a model. Therefore, the cost of research and produce can be reduced.

Active Conical and Planetary Gearing System for Wind Turbines

2012 ◽  
Author(s):  
M. Salim Azzouz ◽  
Anjolajesu Fagbe ◽  
Zachary Evetts ◽  
Ethan Rosales
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Design Theory ◽  
Planetary System ◽  
Experimental Testing ◽  
Electrical Power ◽  
Angular Speed ◽  
Equilibrium Equations ◽  
Input Shaft ◽  
Wind Speeds

The purpose of this research project is to explore the possibility of harvesting the energy of the wind by taking advantage of higher wind speeds. Two active gearbox systems allowing a variable speed at the input shaft and delivering a constant speed at the output shaft are currently being built and tested. The first system consists of an assembly of spur, planetary, and ring gears run and controlled by electrical motors. The second system consists of an assembly of a conical shaft, a wheel, and a set of centrifugal masses. The two gearing systems can act separately as a continuously variable transmission (CVT) between the wind turbine hub and the electricity generator which requires an entry speed corresponding to a frequency of 60 Hz. The two gearing systems are designed using the SolidWorks CAD software for modeling and simulation, and the gearing design theory is used to dimension the required spur, planetary and ring gears for the first proposed system. Betz’s law associated with appropriate and realistic wind turbine efficiency is used to estimate the wind power transferred to the turbine hub. The law is also used to determine the hub angular speed as a function of the wind speed. The kinematic gearing theory is used to establish the different gearing ratios of the planetary system, and the kinematic relationships between the system stages. The forces and torques acting on the first and the second systems are computed using the equilibrium equations. The speed ratios are calculated for the first and second system using the kinematic theory. Ideally, the electrical power consumed by the regulating motor for the first system is minimal so that a maximum percentage of the generated electrical power is supplied to the electricity grid. For the second system the totality of the harvested power is transmitted through the conical/wheel system. For the planetary system, when the wind speed deviates from a certain optimum value, the electrical controls activate a regulating motor to guarantee that the generator input speed remains constant. Currently, a prototype of a more robust planetary gearing system than a previously made one is under construction while a newly constructed conical system is under experimental testing. Running speeds, torques, power transfer and distribution for the two systems will be measured. The generated electrical power is measured using different load resistances and compared to the electrical power consumed by the regulating motor for the planetary system. The torques are measured using a prony brake system while the angular speeds are measured using tachometers. It is expected that the power consumed by the regulating motor for the gearing system will remain a small percentage of the power supplied to the grid for various hub input speeds.

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