Dynamic vibrations in wind energy systems: Application to vertical axis wind turbine

2017 ◽  
Vol 85 ◽  
pp. 396-414 ◽  
Author(s):  
Imen Bel Mabrouk ◽  
Abdelkhalak El Hami ◽  
Lassâad Walha ◽  
Bacem Zghal ◽  
Mohamed Haddar
2019 ◽  
Vol 11 (1) ◽  
pp. 168781401982570 ◽  
Author(s):  
Zheng Li ◽  
Ruihua Han ◽  
Peifeng Gao ◽  
Caisheng Wang

This article investigates a drag-type vertical-axis wind turbine that is targeted for small-scale wind energy system applications. Based on aerodynamics models, the three-dimensional simulation studies have been carried out to obtain the force distributions along blades and eventually the torque and power coefficients for different vertical-axis wind turbine configurations. An optimal vertical-axis wind turbine configuration is chosen based on the comparative analysis, and a 2 kW prototype system has been implemented based on the design. The effectiveness of the three-dimensional models and simulation results has been verified by the measured data from the actual vertical-axis wind turbine system. The wake impacts to the vertical-axis wind turbine caused by nearby objects are also analyzed. The simulation results and the actual operation experiences show that the proposed system has the characteristics of low cut-in speed, high power density, and robustness to adjacent objects (such as buildings and other wind turbines), which make it suitable for small-scale wind energy systems in populated areas including urban environment.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hashwini Lalchand Thadani ◽  
Fadia Dyni Zaaba ◽  
Muhammad Raimi Mohammad Shahrizal ◽  
Arjun Singh Jaj A. Jaspal Singh Jaj ◽  
Yun Ii Go

PurposeThis paper aims to design an optimum vertical axis wind turbine (VAWT) and assess its techno-economic performance for wind energy harvesting at high-speed railway in Malaysia.Design/methodology/approachThis project adopted AutoCAD and ANSYS modeling tools to design and optimize the blade of the turbine. The site selected has a railway of 30 km with six stops. The vertical turbines are placed 1 m apart from each other considering the optimum tip speed ratio. The power produced and net present value had been analyzed to evaluate its techno-economic viability.FindingsComputational fluid dynamics (CFD) analysis of National Advisory Committee for Aeronautics (NACA) 0020 blade has been carried out. For a turbine with wind speed of 50 m/s and swept area of 8 m2, the power generated is 245 kW. For eight trains that operate for 19 h/day with an interval of 30 min in nonpeak hours and 15 min in peak hours, total energy generated is 66 MWh/day. The average cost saved by the train stations is RM 16.7 mil/year with battery charging capacity of 12 h/day.Originality/valueWind energy harvesting is not commonly used in Malaysia due to its low wind speed ranging from 1.5 to 4.5 m/s. Conventional wind turbine requires a minimum cut-in wind speed of 11 m/s to overcome the inertia and starts generating power. Hence, this paper proposes an optimum design of VAWT to harvest an unconventional untapped wind sources from railway. The research finding complements the alternate energy harvesting technologies which can serve as reference for countries which experienced similar geographic constraints.


Author(s):  
Samyak Jain ◽  
Gautam Singh ◽  
Varun Yadav ◽  
Rahul Bisht

Currently, many countries are racing towards switching to clean energy resource (1). Among the options available Solar and Wind are two viable options that are economically feasible. Each day a new development is helping in bringing down the cost of energy extracted from these sources. With currently available technologies, solar energy is almost as expensive as the energy generated from burning coal, whereas wind energy is still slightly expensive (2). However, wind energy could be made cheaper by the use of a vertical axis wind turbine (3). However, structure is a major factor that is holding back the development of VAWTs with better efficiency (4). The efficiency of a VAWT depends upon its aspect ratio. Aspect Ratio is the ratio of the height of the blade to the diameter of the turbine. The lower the aspect ratio, the higher the efficiency (5). However, decreasing the AR would mean either increasing the diameter of the turbine or the height of the blade. In either case, the bending moment would increase on the struts, that connect the blades to the shaft. In this paper we propose, struts with airfoil cross-section. This is because, the lift generated by airfoil struts acts as additional support for the blade, thus increasing our ability to work at lower aspect ratios.


2021 ◽  
Author(s):  
Moshe Zilberman ◽  
Abdelaziz Abu Sbaih ◽  
Ibrahim Hadad

Abstract Wind energy has become an important resource for the growing demand for clean energy. In 2020 wind energy provided more than 6% of the global electricity demand. It is expected to reach 7% at the end of 2021. The installation growth rate of small wind turbines, though, is relatively slow. The reasons we are interested in the small vertical axis wind turbines are their low noise, environmentally friendly, low installation cost, and capable of being rooftop-mounted. The main goal of the present study is an optimization process towards achieving the optimal cost-effective vertical wind turbine. Thirty wind turbine models were tested under the same conditions in an Azrieli 30 × 30 × 90 cm low-speed wind tunnel at 107,000 Reynolds number. The different types of models were obtained by parametric variations of five basic models, maintaining the same aspect ratio but varying the number of bucket phases, the orientation angles, and the gaps between the vanes. The best performing turbine model was made of one phase with two vanes of non-symmetric bipolynomial profiles that exhibited 0.2 power coefficient, relative to 0.16 and 0.13 that were obtained for symmetrical polynomial and the original Savonius type turbines, respectively. Free rotation, static forces and moments, and dynamic moments and power were measured for the sake of comparison and explanation for the variations in performances of different types of turbines. CFD calculations were used to understand the forces and moment behaviors of the optimized turbine.


Wind energy systems are energized by the naturally flowing wind, therefore it can be considered as a fresh source of energy. In addition, the wind energy is accessible as a domestic source of power in many countries worldwide and not bound to just a couple of nations, as on account of oil. However, the output of a wind turbine relies on upon the turbine's size and the wind's speed through the rotor. The amount of power created by the horizontal axis wind turbine is proportional to rotor area and power of wind velocity. In present paper the experimental and analytical study with finite element analysis has been carried out with considering dependent factors like wind speed, number of blades, size of blades to evaluate maximum output power. It is observed that, the eight numbers of blades with 1200mm diameter is more effective in terms of power output.


Author(s):  
Anggara Trisna Nugraha ◽  
Dadang Priyambodo

Indonesia, which is a tropical country, has a very large potential for solar energy because of its area that stretches across the equator, with a radiation magnitude of 4.80 kWh / m2 / day or equivalent to 112,000 GWp. On the other hand, the earth receives solar power of 1.74 x 1017 W / hour and about 1-2% of it is converted into wind energy. However, from the total energy potential, Indonesia has only utilized around 10 MWp for solar energy and not much different, wind energy, whose utilization is planned to reach 250 MW in 2025, has only been utilized around 1 MW of the total existing potential. With this potential, to be able to supply additional power and help save energy for existing facilities in the building, a Prototype of Solar Panel Hybird and Vertical Axis Wind Turbine was created. The design of this prototype is a combination of savonious type turbines and solar panels, where the use of this type of turbine is because it can rotate at low wind speeds (low wind velocity) and its construction is very simple.


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Dieniar N Ramadhani

Much human energy needs are obtained from fossil fuels. This fossil energy is decreasing day by day. So that the utilization of natural energy such as solar energy, water energy and wind energy is being developed. Wind energy is energy that we can find, so it is very easy to use by using a turbine as the driving force. The vertical axis wind turbine is a type of wind turbine that is easier to apply in places where wind potential is not too large. This research was conducted by means of simulation using Qblade v0.963 software by comparing the influence generated from several numbers of wind turbine rotor blades. From the simulation process, it is known that the wind turbine rotor blades with 4 blades are the wind turbines capable of producing the greatest power, which is 75 Watts at a low TSR. So that in the manufacturing process it does not require large costs, but it still has to be built rigid and solidly.


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