Investigations on the Effect of Aspect Ratio Into the Performance of Savonius Rotors

2013 ◽  
Author(s):  
Sukanta Roy ◽  
Ujjwal K. Saha
Keyword(s):  
Aspect Ratio ◽  
Wind Energy ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Maintenance Cost ◽  
Small Scale ◽  
Low Speed ◽  
Aspect Ratios ◽  
Gap Ratio ◽  
Overlap Ratio

With the rapid execution in the renewable energy field, vertical axis wind turbines are finding its application in the small-scale distributed wind energy generation, particularly in rural areas. The Savonius rotor is a drag based vertical axis wind turbine and is used as a small-scale wind energy converter with low installation and maintenance cost. These rotors are simple in design, easy to assemble and can be operated at low-speed wind from any direction. However, these rotors are not gaining popularity because of its low efficiency and improper design. The aspect ratio (height to diameter of the rotor) is one of the very important factors for designing a suitable small-scale wind turbine. The other important factors include overlap ratio, gap ratio and blade profile of the rotor. In the present investigation, a number of rotor models with different aspect ratios are tested in a low speed wind tunnel with open test section facility. The effects of overlap ratio and gap ratio are also studied keeping the rotor height to be the same. The wind speed is varied from 5–10 m/s. To estimate the performance of these rotors, electrical loads are given with respect to different wind speeds and the power output is calculated in terms of voltage and current. The results depicted an optimum aspect ratio of 0.80, which can be used to improve the performance of Savonius rotors.

scholarly journals AIRFOIL SHAPED STRUTS FOR VERTICAL AXIS WIND TURBINE

2021 ◽  
Vol 5 (9) ◽  
Author(s):  
Samyak Jain ◽  
Gautam Singh ◽  
Varun Yadav ◽  
Rahul Bisht
Keyword(s):  
Aspect Ratio ◽  
Wind Energy ◽  
Wind Turbine ◽  
Energy Resource ◽  
Bending Moment ◽  
Clean Energy ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Aspect Ratios ◽  
Cost Of Energy

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.

scholarly journals Evaluation of wind energy potential for different regions in Lebanon based on NASA wind speed database

2021 ◽  
Vol 926 (1) ◽  
pp. 012093
Author(s):  
Y Kassem ◽  
H Çamur ◽  
M A H A Abdalla ◽  
B D Erdem ◽  
A M R Al-ani
Keyword(s):  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Small Scale ◽  
Renewable Energy Resources ◽  
Vertical Axis Wind Turbine ◽  
Energy Potential ◽  
Horizontal Axis Wind Turbine ◽  
Wind Energy Potential

Abstract The grid-connected system can be an attractive solution to reduce electricity consumption, dependence on utility power, and increase electricity generation from renewable energy resources like wind energy for residential electricity users. Based on 33-year wind data (1983-2020), this study investigates the potential of wind energy at different locations ((Akkar, Baalbek, Beirut, Zahlé, Baabda, Nabatieh, Tripoli, and Sidon) in Lebanon using the Weibull distribution function. Monthly NASA wind speed data during the period (1983-2020) were used to estimate the wind energy potential. The result showed that the averaged wind speeds at the selected regions are varied from 3.695m/s to 4.457m/s at the height of 10m. Furthermore, the annual wind power density was estimated at various heights (10m, 30m, and 50m). The results demonstrated that small-scale wind turbines are recommended to be used for generating electricity from wind in the selected regions. Finally, the performance of WRE.060 / 6 kW (vertical axis wind turbine) and Proven WT 6000 (horizontal axis wind turbine) was done based on the monthly NASA wind speed database.

scholarly journals Analysis and implementation of a drag-type vertical-axis wind turbine for small distributed wind energy systems

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401982570 ◽  
Author(s):  
Zheng Li ◽  
Ruihua Han ◽  
Peifeng Gao ◽  
Caisheng Wang
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Three Dimensional ◽  
Energy Systems ◽  
Vertical Axis ◽  
Small Scale ◽  
Prototype System ◽  
Vertical Axis Wind Turbine ◽  
Simulation Results ◽  
Wind Energy Systems

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.

Performance Evaluation of H-Type Darrieus Vertical Axis Wind Turbine with Different Turbine Solidity

2020 ◽  
Vol 17 (2) ◽  
pp. 833-839
Author(s):  
Muhamad Fadhli Ramlee ◽  
Ahmad Fazlizan ◽  
Sohif Mat
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Small Scale ◽  
Stream Velocity ◽  
Wind Condition ◽  
Vertical Axis Wind Turbine ◽  
Power Performance ◽  
Darrieus Rotor

Among renewable energy resources, wind energy is one of the best alternative for power generation. Recently, vertical axis wind turbine (VAWT) received renewed interest as small-scale wind energy converter due to its suitability for urban application, where the wind condition is known to be unsteady and turbulence. Amongst various type of VAWTs, H-type Darrieus rotor has become more popular, thanks to its simple construction features, resulting to low manufacturing and installation cost. The aim of this paper is to evaluate numerically the power performance of straight-bladed Darrieus VAWT with different turbine solidity using computational fluid dynamic (CFD) technology. A series of two-dimensional CFD simulations of a three-bladed H-type Darrieus rotor were performed with 3 different solidities, σ (0.3, 0.5 and 0.7) to evaluate their power performance. Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations were used to calculate the instantaneous moment coefficient, Cm and power coefficient, Cp over a range of tip speed ratio, λ (0.5–4.5) with a free stream velocity of 8.0 m/s. The simulation results show that high solidity turbine performed well at low values of λ while turbine with low solidity has a wider operating range of λ and performed better at λ > 3.0 due to less blade-wake interactions between upstream and downstream halves of the turbine and lower blockage effect. The findings lend substantially to our understanding of physics flow around blades and turbine in order to optimize the power performance of small scale straight-bladed Darrieus VAWT operating in unsteady and turbulence wind condition.

Aerodynamic Performance Characterization of a Drag-Based Elliptical-Bladed Savonius Wind Turbine Rotor

2021 ◽  
Author(s):  
Parag K. Talukdar ◽  
Vinayak Kulkarni ◽  
Ujjwal K. Saha
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Open Circuit ◽  
Power Coefficient ◽  
Small Scale ◽  
Blade Profile ◽  
Savonius Wind Turbine ◽  
Wind Turbine Rotor

Abstract Among the existing wind energy harvesters, the vertical-axis Savonius wind turbine rotor is found to be suitable for small-scale power generation. It is a drag-driven device where the pressure of the fluid stagnating within its blades results in its rotation. The high starting torque and poor operational efficiency of this type of turbine rotor are its distinguishing features. The main geometric and flow parameters that influence its performance are its blade profile, overlap ratio, aspect ratio and Reynolds number (Re). Among these parameters, the blade profile influences significantly on the power production. Recent studies have shown that, choice of an elliptic blade can help in harnessing more wind energy, however, it is desirable to characterize this choice through detailed studies. The present study aims at evaluating the performance of a two-elliptical-bladed Savonius turbine rotor for its dynamic torque and power characteristics. In order to characterize its performances, the developed rotor is experimented in an open circuit low speed wind tunnel. The experiments have been carried out at different Re values so as to estimate the dependence of rotor performance on Re. When the Re is increased from 57310 to 164766, the maximum power coefficient (CPmax) of the turbine rotor has shown an improvement of 43%.

Design and performance evaluation of vertical axis wind turbine for wind energy harvesting at railway

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
Keyword(s):  
Wind Speed ◽  
Energy Harvesting ◽  
Wind Energy ◽  
Wind Turbine ◽  
High Speed ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Modeling Tools ◽  
Content Type

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.

scholarly journals VISUAL ANALYTICS WEB PLATFORM FOR DETECTING HIGH WIND ENERGY POTENTIAL IN URBAN ENVIRONMENTS BY EMPLOYING OGC STANDARDS

2020 ◽  
Vol XLIV-4/W1-2020 ◽  
pp. 71-74
Author(s):  
A. Koukofikis ◽  
V. Coors
Keyword(s):  
Wind Energy ◽  
Visual Analytics ◽  
Vertical Axis ◽  
Urban Environments ◽  
Small Scale ◽  
High Wind ◽  
Energy Potential ◽  
Web Architecture ◽  
Wind Energy Potential ◽  
Ogc Standards

Abstract. We propose a server-client web architecture identifying areas with high wind energy potential by employing 3D technologies and OGC standards. The assessment of a whole city or sub-regions will be supported by integrating Computational Fluid Dynamics (CFD) with historical wind sensor readings. The results, in 3D space, of such analysis could be used for locating installation points of small-scale vertical axis wind turbines in an urban area.

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