Power Augmentation Effects of a Horizontal Axis Wind Turbine With a Tip Vane—Part 2: Flow Visualization

1994 ◽  
Vol 116 (2) ◽  
pp. 293-297 ◽  
Author(s):  
Yukimaru Shimizu ◽  
Takaya Yoshikawa ◽  
Shinji Matsumura
Keyword(s):  
Flow Visualization ◽  
Wind Turbine ◽  
Horizontal Axis ◽  
Tip Vortex ◽  
Inflow Rate ◽  
Horizontal Axis Wind Turbine ◽  
First Report ◽  
Induced Drag ◽  
Blade Tip

This paper presents a discussion of the physics of the flow discussed in our first report (Shimizu, Y. et al., 1990). By visualizing the flow around the tip vane, the following results were drawn: 1) The strength of the tip vortex, the induced drag and turbulence on the blade tip can be diminished with a tip vane. 2) The inflow rate to the rotary surface of wind turbine can be increased with the tip vane.

scholarly journals Efficient contribution of partially tip cascaded horizontal-axis wind turbine

2019 ◽  
Vol 11 (11) ◽  
pp. 168781401989211
Author(s):  
Deyaa Nabil Elshebiny ◽  
Ali AbdelFattah Hashem ◽  
Farouk Mohammed Owis
Keyword(s):  
Wind Turbine ◽  
Aerodynamic Performance ◽  
Operating Conditions ◽  
Horizontal Axis ◽  
National Renewable Energy Laboratory ◽  
Horizontal Axis Wind Turbine ◽  
Ansys Fluent ◽  
Knowing That ◽  
Turbine Performance ◽  
Blade Tip

This article introduces novel blade tip geometric modification to improve the aerodynamic performance of horizontal-axis wind turbine by adding auxiliary cascading blades toward the tip region. This study focuses on the new turbine shape and how it enhances the turbine performance in comparison with the classical turbine. This study is performed numerically for National Renewable Energy Laboratory Phase II (non-optimized wind turbine) taking into consideration the effect of adding different cascade configurations on the turbine performance using ANSYS FLUENT program. The analysis of single-auxiliary and double-auxiliary cascade blades has shown an impact on increasing the turbine power of 28% and 76%, respectively, at 72 r/min and 12.85 m/s of wind speed. Knowing that the performance of cascaded wind turbine depends on the geometry, solidity and operating conditions of the original blade; therefore, these results are not authorized for other cases.

A Simplified Free Wake Method for Horizontal-Axis Wind Turbine Performance Prediction

1986 ◽  
Vol 108 (4) ◽  
pp. 400-406 ◽  
Author(s):  
A. A. Afjeh ◽  
T. G. Keith
Keyword(s):  
Wind Turbine ◽  
Performance Prediction ◽  
Vortex Method ◽  
Computational Effort ◽  
Horizontal Axis ◽  
Tip Vortex ◽  
Performance Parameters ◽  
Horizontal Axis Wind Turbine ◽  
Turbine Performance ◽  
Free Wake

Based on the assumption that wake geometry of a horizontal-axis wind turbine closely resembles that of a hovering helicopter, a method is presented for predicting the performance of a horizontal-axis wind turbine. A vortex method is used in which the wake is composed of an intense tip-vortex and a diffused inboard wake. Performance parameters are calculated by application of the Biot-Savart law along with the Kutta-Joukowski theorem. Predictions are shown to compare favorably with values from a more complicated full free wake analysis and with existing experimental data, but require more computational effort than an existing fast free wake method.

Prediction of Ice Accretion on Wind Turbine with Numerical Method

2012 ◽  
Vol 512-515 ◽  
pp. 754-757
Author(s):  
Xian Yi ◽  
Kai Chun Wang ◽  
Hong Lin Ma
Keyword(s):  
Wind Turbine ◽  
Numerical Method ◽  
Collection Efficiency ◽  
Three Dimensional ◽  
Horizontal Axis ◽  
Ice Accretion ◽  
Horizontal Axis Wind Turbine ◽  
Blade Tip ◽  
Computer Codes ◽  
Multiple Reference

A three dimensional numerical method and its computer codes, which are suitable to predict the process of horizontal axis wind turbine icing, are presented. The method is composed of the Multiple Reference Frame (MRF) method to calculate flowfield of air, an Eulerian method to compute collection efficiency and a three dimensional icing model companying with an iterative arithmetic for solving the model. Ice accretion on a 1.5 MW horizontal axis wind turbine is then computed with the numerical method, and characteristics of droplet collection efficiency and ice shape/type are obtained. The results show that ice on the hub and blade root is slight and it can be neglected comparing with ice near blade tip. From blade tip to root, ice becomes thinner and glaze ice may changes into rime ice.

scholarly journals Aerodynamic Investigation of a Horizontal Axis Wind Turbine with Split Winglet Using Computational Fluid Dynamics

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4983 ◽  
Author(s):  
Miguel Sumait Sy ◽  
Binoe Eugenio Abuan ◽  
Louis Angelo Macapili Danao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Renewable Energy ◽  
Wind Turbine ◽  
Renewable Energy Sources ◽  
Horizontal Axis ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Blade Tip ◽  
Nrel Phase Vi

Wind energy is one of the fastest growing renewable energy sources, and the most developed energy extraction device that harnesses this energy is the Horizontal Axis Wind Turbine (HAWT). Increasing the efficiency of HAWTs is one important topic in current research with multiple aspects to look at such as blade design and rotor array optimization. This study looked at the effect of wingtip devices, a split winglet, in particular, to reduce the drag induced by the wind vortices at the blade tip, hence increasing performance. Split winglet implementation was done using computational fluid dynamics (CFD) on the National Renewable Energy Lab (NREL) Phase VI sequence H. In total, there are four (4) blade configurations that are simulated, the base NREL Phase VI sequence H blade, an extended version of the previous blade to equalize length of the blades, the base blade with a winglet and the base blade with split winglet. Results at wind speeds of 7 m/s to 15 m/s show that adding a winglet increased the power generation, on an average, by 1.23%, whereas adding a split winglet increased it by 2.53% in comparison to the extended blade. The study also shows that the increase is achieved by reducing the drag at the blade tip and because of the fact that the winglet and split winglet generating lift themselves. This, however, comes at a cost, i.e., an increase in thrust of 0.83% and 2.05% for the blades with winglet and split winglet, respectively, in comparison to the extended blade.

EFFECTIVENESS OF BLADE TIP ON LOW SPEED HORIZONTAL AXIS WIND TURBINE PERFORMANCE

2016 ◽  
Vol 78 (8-4) ◽  
Author(s):  
Muhammad Hafidz Ariffudin ◽  
Fazila Mohd Zawawi ◽  
Haslinda Mohamed Kamar ◽  
Nazri Kamsah
Keyword(s):  
Wind Turbine ◽  
High Efficiency ◽  
Turbine Blades ◽  
Horizontal Axis ◽  
Tip Vortex ◽  
Wind Turbine Blades ◽  
Horizontal Axis Wind Turbine ◽  
Low Speed ◽  
Low Wind Speed ◽  
Turbine Performance

There has been an increasing demand for renewable energy in order to create a sustainable society as the non-renewable energies such as fossil fuel resources are limited. Modern wind turbines claim that they have a high efficiency in term of wind energy extraction. However, there are still having losses due to tip vortex causing to a reduction in performance.  Motivated by this reason, this research aims at exploring the possibility to increase the performance of low speed small-scaled horizontal axis wind turbine with various tip devices using Computational Fluid Dynamics (CFD). Four wind turbine blades with different tip devices which consist of sword tip, swept tip, upwind winglet and downwind winglet are compared with wind turbine blade without tip device in term of CP. The application of tip device can significantly reduce induced tip vortex and improve wind turbine performance. For TSR below than 4, adding a sword tip increases CP about 7.3%, swept tip increases CP about 9.1%, upwind winglet increases CP about 1.8% and downwind winglet increases CP about 3.2%. It is observed that the best tip device for low wind speed application is swept tip as it give the highest performance increment compared to without tip device.

PIV Experiment on Near Wake Flow of Horizontal Axis Wind Turbine

2013 ◽  
Vol 718-720 ◽  
pp. 1811-1815 ◽  
Author(s):  
Xiang Gao ◽  
Jun Hu ◽  
Zhi Qiang Wang
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Radial Direction ◽  
Three Dimensional ◽  
Horizontal Axis ◽  
Tip Vortex ◽  
Wake Flow ◽  
Horizontal Axis Wind Turbine ◽  
Near Wake ◽  
Piv Measurement

A three-dimensional horizontal axis wind turbine model was experimentally studied. The experiment was carried out in a laboratory wind tunnel. With PIV measurement, details about flow fields in the near wakeof the turbine blade were obtained. The result shows vortices generateon the tailing edge of the blade, and propagatedownstream then dissipate into small vortices. Vortices also generate at the tip of the blade, propagate downstream and along the radial direction then dissipate. The dissipation of the tip vortex is slower than the former. We also find that the wake of turbine blade rotates in the opposite direction of the blade.

scholarly journals Effect of liquid water content on blade icing shape of horizontal axis wind turbine by numerical simulation

2019 ◽  
Vol 23 (3 Part A) ◽  
pp. 1637-1645
Author(s):  
Yan Li ◽  
Ce Sun ◽  
Yu Jiang ◽  
Xian Yi ◽  
Yingwei Zhang
Keyword(s):  
Wind Turbine ◽  
Water Content ◽  
Liquid Water ◽  
Large Scale ◽  
Liquid Water Content ◽  
Horizontal Axis ◽  
Computation Method ◽  
Layer By Layer ◽  
Horizontal Axis Wind Turbine ◽  
Blade Tip

To research the law of the icing accretes on near the tip part of rotating blade of large-scale horizontal axis wind turbine (HAWT) influenced by liquid water content (LWC), the icing distribution on a HAWT rotor with rated power of 1.5 MW was simulated based on a Quasi-3D computation method. About 30% part length of blade from tip along span wise to blade root which are the most serious icing area was selected to research. Eight sections of this 30% part were decided and the ice distribution on each sections were simulated. Five kinds of LWC from 0.2 g/m3 to 1.4 g/m3 and two kinds of temperatures including ?6?C and ?18?C were selected. The medium volume droplet is 30 mm. Three kinds of icing time were selected to analyze the effects of icing time on ice accretion. The icing shape evaluate method was applied to quantitatively analyze the icing shape obtatined under different conditions. The results show that the icing shapes are all horn icing shape under the different LWC when the temperature is ?6?C. The icing shapes change from horn icing shape to streamline icing shape with LWC increasing under the temperature of ?18?C. The icing accretes on blade surface layer by layer with icing time increasing. The closer the section blade tip, the more icing accretes. This study can be as reference for the research on anti-icing and de-icing technologies for large-scale HAWT.

Application of the Reynolds Stress Model to Direct Modeling and Actuator Disk Simulations of a Small-Scale Horizontal-Axis Wind Turbine

2016 ◽  
Author(s):  
Randall Jackson ◽  
Ryoichi S. Amano
Keyword(s):  
Wind Turbine ◽  
Reynolds Stress ◽  
Reynolds Stress Model ◽  
Horizontal Axis ◽  
Tip Vortex ◽  
Small Scale ◽  
Stress Model ◽  
Closure Model ◽  
Horizontal Axis Wind Turbine ◽  
Turbulence Closure Model

Computational Fluid Dynamics (CFD) has become a staple in wind energy research and studies cover a broad range of topics including atmospheric wind profiles, airfoil design, wind turbine design, terrain effects, and wake dynamics. One of the most important aspects of applying CFD methods is the selection of a turbulence closure model when solving the Reynolds Averaged Navier-Stokes (RANS) equations. In this research, the Reynolds Stress Model (RSM) was applied to predict the wake turbulence and velocity profiles for a small scale, 3-bladed, horizontal-axis wind turbine (HAWT) using a commercial CFD software, Star CCM+. The wind turbine was modeled directly by discretizing the rotor and also using an actuator disc concept to simulate the rotor. Wind tunnel experiments were performed using hot-wire anemometry to measure the velocity deficit at various downstream locations. High speed images were also captured to examine qualitatively the wake and tip vortex dissipation created from an oil mist. The CFD results show the RSM turbulence closure model to be excellent in predicting the wake velocity and tip vortex structure when compared to experimental results.

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