Hybrid/Combined Darrieus–Savonius Wind Turbines: Erstwhile Development and Future Prognosis

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Jyotirmoy Sarma ◽  
Siddhant Jain ◽  
Prasenjit Mukherjee ◽  
Ujjwal K. Saha
Keyword(s):  
Wind Turbines ◽  
Wind Direction ◽  
Review Paper ◽  
Past Research ◽  
Vertical Axis ◽  
Combined System ◽  
Future Studies ◽  
The Past ◽  
Vertical Axis Wind Turbines ◽  
Design Simplicity

Abstract Over the last few decades, the vertical-axis wind turbines (VAWTs) have undergone intensive research mainly due to their design simplicity and independency of wind direction. The drag-based Savonius wind rotor exhibits a better starting capability, whereas the lift-based Darrieus wind rotor achieves higher efficiency over a wider operating range. Thus, in order to capitalize on their advantages, both the rotors are mounted on the same axis to form a hybrid/combined system. In this review paper, an attempt has been made to collect and analyze the past research studies in the field of hybrid wind rotors. An optimization route has also been suggested for the design of such a hybrid wind rotor to ensure that the design complexity is minimized, and at the same time, both the Savonius and the Darrieus rotors are utilized to their fullest potential. In this regard, a few important parameters are identified whose effects on the hybrid rotor performance must be investigated in future studies. Suggestions and direction of research are presented keeping in mind the improvement of the technology.

Designing and Analyzing Savonius Wind Turbines

2019 ◽  
Author(s):  
Varun Kumar Reddy Manne ◽  
Hong Zhou
Keyword(s):  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Wind Turbines ◽  
Wind Direction ◽  
High Reliability ◽  
Power Conversion ◽  
Vertical Axis ◽  
Geometric Parameters ◽  
Vertical Axis Wind Turbines ◽  
Static Torque

Abstract Savonius wind turbines are drag-type vertical axis wind turbines. Their blades experience less drag while moving against the wind flow and more drag while moving in the wind direction. The drag difference rotates Savonius wind turbines and produces electrical power. Savonius wind turbines can catch wind from any direction. No yaw motion mechanism is needed for them to be pointed in the wind direction. Savonius wind turbines have simple structures and are convenient to install and maintain. They can operate on low wind speed and have good starting characteristics. Compared with horizontal axis wind turbines and lift-type vertical axis wind turbines such as Darrieus and Giromill wind turbines, Savonius wind turbines have relatively low power conversion efficiency. This is because of their drag-type nature which generates positive and negative torque on their advancing and returning blades, respectively. Savonius wind turbines are suitable for locations where power conversion efficiency can be compromised for the sake of low cost and high reliability. One major drawback from Savonius wind turbines is the negative static torque which lowers their self-starting ability. Although the negative static torque of Savonius wind turbines can be mitigated by adding additional components such as curtains, nozzles and ducts to them, these additional components make them complex and lose omnidirectional performance. In this paper, Savonius wind turbines are designed based on their geometric parameters to remove their negative static torque and improve their performance. Savonius wind turbines with different numbers of blades and other geometric parameters are designed, analyzed and simulated.

Slewing Effect of Twin Vertical Axis Turbines Supported by a Floating Platform Able to Rotate Around a Single Mooring System

2018 ◽  
Author(s):  
Kazuma Kusanagi ◽  
Sharath Srinivasamurthy ◽  
Yasunori Nihei
Keyword(s):  
Wind Turbines ◽  
Wind Direction ◽  
Clean Energy ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Mooring System ◽  
Wind Condition ◽  
Vertical Axis Wind Turbines ◽  
New Type ◽  
New System

In this study, we propose a new and innovative solution for harnessing offshore wind using vertical axis wind turbines (VAWT). The new type of FOWT is termed as Twin connection VAWT which uses single point mooring system consisting of two turbines capable of aligning itself against any wind direction. New-type vertical axis wind turbines are designed and developed by some of the present authors which are supported by separate floaters. The conceptual development and working mechanism of the proposed Twin connection VAWT is described in this paper based on experimental results. The yawing motion of proposed system about the moored point aligning itself to the direction of wind is confirmed in a series of dedicated experiments under only-wind condition. After aligning itself and turbines facing the direction of the wind, slow varying slewing motion phenomenon is observed during experiments. The wind forces acting on two VAWTs is examined in x-y plane and it is predicted that the forces acting perpendicular to the wind direction explains the slewing phenomenon. A physics model is conceptualized and developed to understand the yawing mechanism of the new system. A numerical simulation code is also developed to understand the yaw motion around the moored point using the steering motion equations. It is confirmed how the new system proposed can be utilized for generating clean energy.

scholarly journals Numerical Analysis of the Dynamic Interaction between Two Closely Spaced Vertical-Axis Wind Turbines

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2286
Author(s):  
Yutaka Hara ◽  
Yoshifumi Jodai ◽  
Tomoyuki Okinaga ◽  
Masaru Furukawa
Keyword(s):  
Wind Turbines ◽  
Power Distribution ◽  
Phase Synchronization ◽  
Average Power ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Mean Power ◽  
Vertical Axis Wind Turbines ◽  
Fluid Body ◽  
First Time

To investigate the optimum layouts of small vertical-axis wind turbines, a two-dimensional analysis of dynamic fluid body interaction is performed via computational fluid dynamics for a rotor pair in various configurations. The rotational speed of each turbine rotor (diameter: D = 50 mm) varies based on the equation of motion. First, the dependence of rotor performance on the gap distance (gap) between two rotors is investigated. For parallel layouts, counter-down (CD) layouts with blades moving downwind in the gap region yield a higher mean power than counter-up (CU) layouts with blades moving upwind in the gap region. CD layouts with gap/D = 0.5–1.0 yield a maximum average power that is 23% higher than that of an isolated single rotor. Assuming isotropic bidirectional wind speed, co-rotating (CO) layouts with the same rotational direction are superior to the combination of CD and CU layouts regardless of the gap distance. For tandem layouts, the inverse-rotation (IR) configuration shows an earlier wake recovery than the CO configuration. For 16-wind-direction layouts, both the IR and CO configurations indicate similar power distribution at gap/D = 2.0. For the first time, this study demonstrates the phase synchronization of two rotors via numerical simulation.

Optimal Placement of Horizontal- and Vertical-Axis Wind Turbines in a Wind Farm for Maximum Power Generation Using a Genetic Algorithm

2011 ◽  
Author(s):  
Xiaomin Chen ◽  
Ramesh Agarwal
Keyword(s):  
Genetic Algorithm ◽  
Wind Turbines ◽  
Wind Farm ◽  
Optimization Problem ◽  
Vertical Axis ◽  
Optimal Placement ◽  
Vertical Axis Wind Turbines ◽  
Wake Effects ◽  
Horizontal Axis Wind Turbines ◽  
Wake Model

In this paper, we consider the Wind Farm layout optimization problem using a genetic algorithm. Both the Horizontal–Axis Wind Turbines (HAWT) and Vertical-Axis Wind Turbines (VAWT) are considered. The goal of the optimization problem is to optimally place the turbines within the wind farm such that the wake effects are minimized and the power production is maximized. The reasonably accurate modeling of the turbine wake is critical in determination of the optimal layout of the turbines and the power generated. For HAWT, two wake models are considered; both are found to give similar answers. For VAWT, a very simple wake model is employed.

Vertical axis wind turbine operation in icing conditions: A review study

2021 ◽  
pp. 0309524X2110618
Author(s):  
Syed Abdur Rahman Tahir ◽  
Muhammad Shakeel Virk
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Vertical Axis ◽  
Electricity Production ◽  
Vertical Axis Wind Turbine ◽  
Vertical Axis Wind Turbines ◽  
Horizontal Axis Wind Turbines ◽  
Promising Solution ◽  
Review Study ◽  
Accretion Physics

Vertical Axis Wind Turbine (VAWT) can be a promising solution for electricity production in remote ice prone territories of high north, where good wind resources are available, but icing is a challenge that can affect its optimum operation. A lot of research has been made to study the icing effects on the conventional horizontal axis wind turbines, but the literature about vertical axis wind turbines operating in icing conditions is still scarce, despite the importance of this topic. This paper presents a review study about existing knowledge of VAWT operation in icing condition. Focus has been made in better understanding of ice accretion physics along VAWT blades and methods to detect and mitigate icing effects.

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