Performance Enhancement of a Savonius Vertical Axis Wind Turbine with Bio-Inspired Design Modifications
01 Jan 2021-pp 449-457
TL;DR: In this article, a Savonius-type vertical-axis wind turbine (VAWT) is proposed to improve the efficiency by incorporating the concept of dimples on the negative side of the rotor blade and tubercles on the leading edge of the turbine blade.
Abstract: One of the prime commodities in modern civilization is energy. The amount of energy consumption has become the indicator for the standard of living and the degree of industrialization. People use fossil fuels to meet nearly all of their energy needs, such as powering vehicles, producing electricity for light and heat and running factories, thus greatly exhausting the fossil fuel reserves along with polluting the environment with greenhouse gases. Renewable energy sources are viable alternatives, and among the various types of renewable energy sources available, wind energy is the sector which has a lot of untapped potential. Our objective is to improve the efficiency of a Savonius-type vertical-axis wind turbine (VAWT) which currently has the least efficiency among existing wind turbine designs. Savonius turbines have a very compact structure and can run at low wind speeds which are desirable characteristics for commercial-scale power production. This research paper focuses on improving the efficiency of Savonius wind turbine. Since Savonius-type wind turbines are drag-based wind turbines, we need to reduce the impulsive force acting on the negative face in order to increase the drag difference between the positive and negative side of the rotor blades thereby improving the efficiency of the turbine. Our proposition for attaining higher efficiency is by incorporating the concept of dimples (inspired from golf ball) on the negative side of the rotor blade and tubercles (inspired from whales) on the leading edge of the rotor blade. Dimples reduce the amount of wake region in the case of golf ball by increasing turbulence which is one of the desirable characteristics in the case of Savonius wind turbine. Tubercles help in reducing the wake region behind the rotor blades by increasing the turbulence of air near the surface of the rotor thereby improving the efficiency of the turbine.
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TL;DR: In this paper, different geometries of Savonius wind turbine are experimentally studied in order to determine the most effective operation parameters, it was found that, the two blades rotor is more efficient than three and four ones.
Abstract: For solving the world energy problem and the bad effect of conventional sources of energy on environment, great attention allover the world is paid towards the use of renewable energy sources. Special interest is paid towards wind energy because of its competitively.
Savonius rotor is a vertical axis wind turbine which is characterized as cheaper, simpler in construction and low speed turbine. This makes it suitable for generating mechanical energy in many countries especially in Egypt.
In this work different geometries of Savonius wind turbine are experimentally studied in order to determine the most effective operation parameters. It was found that, the two blades rotor is more efficient than three and four ones. The rotor with end plates gives higher efficiency than those of without end plates. Double stage rotors have higher performance compared to single stage rotors. The rotors without overlap ratio (β) are better in operation than those with overlap. The results show also that the power coefficient increases with rising the aspect ratio (α). The conclusions from the measurements of the static torque for each rotor at different wind speeds verify the above summarized results of this work.
231 citations
TL;DR: In this paper, the performance of single stage (rotor aspect ratio of 1.0), two-stage and three-stage Savonius rotors were compared at different Reynolds numbers and compared at the same Reynolds number.
Abstract: The performance of single stage (rotor aspect ratio of 1.0), two stage Savonius rotor with rotor aspect ratios of 1.0 and 2.0 (stage aspect ratios of 0.50 and 1.0) and three stage Savonius rotor with rotor aspect ratios of 1.0 and 3.0 (stage aspect ratios of 0.33 and 1.0) are studied at different Reynolds numbers and compared at the same Reynolds number. The results show that the coefficient of power and the coefficient of torque increase with the increase in the Reynolds numbers for all the rotors tested. The coefficient of static torque is independent of the Reynolds number for all the rotors tested. The performance of two stage and three stage rotors remains the same even after increasing the stage aspect ratio and the rotor aspect ratio by a factor of two and three, respectively. For the same rotor aspect ratio of 1.0, by increasing the number of stages (stage aspect ratio decreases), the performance deteriorates in terms Cp and Ct. However, at the same stage aspect ratio of 1.0 and same Reynolds number, two and three stage rotors show the same performance in terms of coefficient of power and coefficient of torque. The variation in coefficient of static torque is lower for a three stage rotor when compared with the variation of coefficient of static torque for two stage or single stage rotor. Copyright © 2008 John Wiley & Sons, Ltd.
131 citations
TL;DR: In this article, a three-blade horizontal axis wind turbine (HAWT) and a Darrieus-type vertical axis wind turbines (VAWT) have been designed with CATIA software and constructed using a 3D-printing method.
Abstract: As the demand for green technology is rising rapidly worldwide, it is important that Malaysian researchers take advantage of Malaysia’s windy climates and areas to initiate more power generation projects using wind. The main objectives of this study are to build a functional wind turbine and to compare the performance of two types of design for wind turbine under different speeds and behaviours of the wind. A three-blade horizontal axis wind turbine (HAWT) and a Darrieus-type vertical axis wind turbine (VAWT) have been designed with CATIA software and constructed using a 3D-printing method. Both wind turbines have undergone series of tests before the voltage and current output from the wind turbines are collected. The result of the test is used to compare the performance of both wind turbines that will imply which design has the best efficiency and performance for Malaysia’s tropical climate. While HAWT can generate higher voltage (up to 8.99 V at one point), it decreases back to 0 V when the wind angle changes. VAWT, however, can generate lower voltage (1.4 V) but changes in the wind angle does not affect its voltage output at all. The analysis has proven that VAWT is significantly more efficient to be built and utilized for Malaysia’s tropical and windy climates. This is also an initiative project to gauge the possibility of building wind turbines, which could be built on the extensive and windy areas surrounding Malaysian airports.
74 citations
TL;DR: In this paper, the authors provide some basic guidelines on the optimum design staring from the historical design, recent developments, and opportunities, as well as some challenges on trends are discussed with novel ideas of some future wind energy harvesting designs for enhanced applications at greater efficiency.
Abstract: The vast dimensions of the renewable energy field have drawn diverse approaches, resources, and results for a long time. The continual changing behaviors and cycles of renewable energy have encouraged novel developments over the years with most commonly used approaches being three blade designs mounted on a rotor and are commonly used to harvest onshore and offshore wind energy. The renewable energy field is extremely dynamic and perplexing, thus creating a heavy interest in discovering the most economical, efficient, and reliable method to harvest renewable wind energy. Producing energy through the wind is well proven and widely used method with current activities focused on improving efficiency, performance, and reliability. A major challenge of wind energy is that it is available only when and where winds prevail. The electricity produced must be used instantly or stored for use in times when none to limited winds exist. The developments of blades have been based on the aircraft propeller design but extended over a larger area to capture much energy from the wind. This paper provides some basic guidelines on the optimum design staring from the historical design, recent developments, and opportunities. Some challenges on trends are discussed with novel ideas of some future wind energy harvesting designs for enhanced applications at greater efficiency.
48 citations