Optimal Design of Wind Boosters for Low Speed Vertical Axis Wind Turbines

2015 ◽  
Vol 798 ◽  
pp. 195-199 ◽  
Author(s):  
Natapol Korprasertsak ◽  
Thananchai Leephakpreeda

Although Vertical Axis Wind Turbines (VAWTs) are designed for performing mechanical works acceptably at medium wind speed, Standalone VAWTs are still unable to generate mechanical power satisfactorily for best practice at low speed wind. This study presents optimal design of wind booster, by utilizing Computational Fluid Dynamics (CFD). A wind booster is proposed to be implemented with a VAWT in order to not only harvest energy with low availability at low wind speed but also enhance performance of a VAWT at higher wind speed. In CFD-based experiments, guiding and throttling effects of the wind booster are able to increase mechanical power of a VAWT. Optimal alternatives of number and leading angle of guide vanes are determined by maximizing the coefficient of power from the alternating direction method as an optimization technique. The VAWT coupled with the optimal wind booster, which consists of 8 guide vanes and leading angle of 55o, is cable of producing mechanical power higher up to the coefficient of power of 4.8 % than the original design.

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879954
Author(s):  
Soo-Yong Cho ◽  
Sang-Kyu Choi ◽  
Jin-Gyun Kim ◽  
Chong-Hyun Cho

In order to augment the performance of vertical axis wind turbines, wind power towers have been used because they increase the frontal area. Typically, the wind power tower is installed as a circular column around a vertical axis wind turbine because the vertical axis wind turbine should be operated in an omnidirectional wind. As a result, the performance of the vertical axis wind turbine depends on the design parameters of the wind power tower. An experimental study was conducted in a wind tunnel to investigate the optimal design parameters of the wind power tower. Three different sizes of guide walls were applied to test with various wind power tower design parameters. The tested vertical axis wind turbine consisted of three blades of the NACA0018 profile and its solidity was 0.5. In order to simulate the operation in omnidirectional winds, the wind power tower was fabricated to be rotated. The performance of the vertical axis wind turbine was severely varied depending on the azimuthal location of the wind power tower. Comparison of the performance of the vertical axis wind turbine was performed based on the power coefficient obtained by averaging for the one periodic azimuth angle. The optimal design parameters were estimated using the results obtained under equal experimental conditions. When the non-dimensional inner gap was 0.3, the performance of the vertical axis wind turbine was better than any other gaps.


2020 ◽  
Vol 12 (18) ◽  
pp. 7818
Author(s):  
Jose Alberto Moleón Baca ◽  
Antonio Jesús Expósito González ◽  
Candido Gutiérrez Montes

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.


Author(s):  
Saowalak Thongdee ◽  
Churat Tararuk ◽  
Natthawud Dussadee ◽  
Rameshprabu Ramaraj ◽  
Tanate Chaichana

This research aimed to compare the performance of Savonius vertical axis wind turbines through blade numbers and different blade angles. In this study, applicable turbines having 4, 6, 8, 12, 16 and 18 numbers of blades with the angles of the blades of -15°, -5°, 0°, 5° and 15°, respectively. The rotor used was a semicircle shaped blade made from PVC material and has a blade diameter of 6 cm and 30 cm for both rotor diameter and height. The turbine was tested deadweight range of 0-0.49 kg at 4 m/s wind speed. The results showed that the blade angle has a positive effect on increasing the power and torque coefficient of Savonius wind turbine, specifically on blades less than 16. The highest power and torque coefficient was obtained from the turbine having16 blades at an angle of 5°. This configuration also found that the maximum power and torque coefficient in the tip speed ratio ranging from 0.3-0.4 are 0.2519 and 0.5858, respectively.


2014 ◽  
Vol 953-954 ◽  
pp. 395-399 ◽  
Author(s):  
Lih Shyng Shyu

The purpose of this study is to investigate the parameters that affect the cost-effectiveness of wind farm land use and wind energy harvesting efficiency. The research team applies two reverse rotating vertical-axis wind turbines (VAWTs) to explore how wind speed and various distances of wind turbines affect the operation efficiency of a prospective wind farm. A data acquisition system has been constructed to record the wind speed along with a variety of wind turbine output data in a wind tunnel test in order to identify the layout that help to achieve the best wind harvesting efficiency. The layout is then applied in the field test for further observation and data collection. The experiment results show 1) when two VAWTs are moved toward each other (from 300 cm to 180 cm), both turbines observe performance gain, and 2) when two VAWTs are set at a distance of 1.5 to 2.0 times the turbine diameter, the performance of both units increases by about 11% over the efficiency obtainable by their stand-alone counterpart.


2014 ◽  
Vol 1016 ◽  
pp. 554-558 ◽  
Author(s):  
Natapol Korprasertsak ◽  
Nataporn Korprasertsak ◽  
Thananchai Leephakpreeda

In Thailand, the average wind speed is generally quite low (≈ 3 - 4 m/s). Although Vertical Axis Wind Turbines (VAWTs) are designed for low speed wind, standalone VAWTs are still unable to generate power satisfactorily under that practical condition. This study introduces a new design of a wind flow controlling device, called a “wind booster”, by utilizing Computational Fluid Dynamics (CFD). A wind booster is developed for incorporating with a VAWT in order to increase the performance of the VAWT and to overcome the limitation of harvesting energy with low availability at low speed wind. The guiding and throttling effects of the optimal design of the wind booster are able to increase the angular velocity of VAWTs which leads to an increase in power generated from VAWTs.


2019 ◽  
Vol 13 ◽  
Author(s):  
Li Zheng ◽  
Zhang Wenda ◽  
Han Ruihua ◽  
Qi Weiqiang

Background: In a wind farm, the wind speed of the downstream wind turbine will be lower than the wind speed of the upstream wind turbine due to the influence of the wake. Therefore, the wake of wind turbines is one of the uncertain factors predicting the annual power generation of wind farms. The study of the wake can effectively improve the efficiency of power generation. The arrangement of vertical axis wind turbines in wind farms is rarely studied. Therefore, it is important to study the vertical layout of wind turbines under the influence of wakes to obtain the best layout and unit spacing. Objective: To obtain the optimal layout and unit distance of wind turbines in Senegal wind turbines by studying the arrangement of Senegal vertical axis wind turbines in wind farms. Method: Based on the ANSYS CFX flow field calculation module, the fluid dynamics model of the Senegal fan was established and the flow field simulation analysis was carried out. Based on the Jensen wake model and its improved model, three layout methods for wind farm wind turbines are proposed: two units are arranged in series, two units are arranged in parallel, and three units are staggered. Through the simulation model, the wind energy utilization coefficient and wind speed of the wind turbine in the wind farm are obtained. Results: The optimal separation distance between the units was analyzed from four different angles: wind energy utilization coefficient, torque analysis, downstream tail flow and wind speed cloud contour. Finally, based on the optimal arrangement and unit distance, a triangular staggered wind farm composed of 10 units is established, and the integrated flow field characteristics of the whole wind farm are simulated and analyzed. The integrated flow field wake characteristics of the wind farm are obtained. Conclusion: In all three arrangements, the optimum distance between the units should be three times the diameter of the wind turbine. This arrangement ensures that most of the units are unaffected by the wake, the area affected by the low velocity wake of the wind farm is small, and the area affected by the high speed wake is large.


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