Numerical Study of Effects of AJVG on Aerodynamic Performance and Speed Control of Small-Scale Fixed-Pitch HAWT

2014 ◽  
Author(s):  
Xiang Gao ◽  
Jun Hu ◽  
Zhiqiang Wang ◽  
Chenkai Zhang
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Output Power ◽  
Vortex Generator ◽  
Speed Control ◽  
Aerodynamic Performance ◽  
Small Scale ◽  
Air Jet ◽  
Blade Tip ◽  
Fixed Pitch

Due to the feature of structure simplicity, lower production cost and maintenance ease, fixed pitch variable speed wind turbine has been widely used in non-grid-connected wind power systems. The calculation of wind turbine performance plays an important part in the design of wind turbines. Aerodynamic performance calculation is particularly significant in the fixed pitch stall-regulated wind turbine aerodynamic design process. To enhance the output power and power coefficient of wind turbine, active flow control technologies such as vortex generator are adopted in recent years. In this paper, a small wind turbine with air jet vortex generator (AJVG) on the blade tip is designed, and the output power of the wind turbine gets changed by operating the air jet. Computational Fluid Dynamics method is chosen to obtain aerodynamic characteristics of the wind turbine with/without AJVG and these features are furtherly integrated with speed control method to get speed control strategy under full-speed circumstance. It can be found after complete comparison that through setting AJVG at the blade tip, the new speed control features can help make it operate more stably in a wide range of wind speed without changing the existing wind turbine blades profiles and pitch angle. Also details of the flow field are obtained when solving the three-dimensional Navier-Stokes Equations. By analyzing the flow field of wind turbine with/without AJVG, the influence mechanism of the AJVG is demonstrated in this paper.

Numerical Simulation of the 1.2MW Wind Turbine Flow-Field

2011 ◽  
Vol 383-390 ◽  
pp. 2045-2050
Author(s):  
Shao Hua Li ◽  
Qing Feng Kuang ◽  
Wei Peng Yue ◽  
Ting Ting Guo
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Output Power ◽  
Simple Algorithm ◽  
3D Models ◽  
Aerodynamic Performance ◽  
Field Region ◽  
Control Equation ◽  
Volume Method ◽  
The Relationship

Based on SIMPLE algorithm, with the control equation in finite volume method and the SST K- φturbulence model, 3D models of the 1.2MW wind turbine are built to analyze the relationship between the output power and the pressure, velocity and turbulent kinetic energy of its different sections. The results show that: The change of aerodynamic performance which is caused by the interaction of blades and tower , reduces the available torque of the wind turbine that caused the decreases of the output power. The flow field region affected by central swirl and adhesive vortex is very small. The region of velocity field was affected by the wheel and wind turbine, even a few hundred meters away, but the region affected by wind turbine was smaller than by the wheel.

scholarly journals A Comparison of Isolated and Ducted Fixed-Pitch Propellers under Non-Axial Inflow Conditions

Aerospace ◽  
2020 ◽  
Vol 7 (8) ◽  
pp. 112
Author(s):  
Michael Cerny ◽  
Christian Breitsamter
Keyword(s):  
Flow Field ◽  
Unmanned Aerial Vehicles ◽  
Systematic Investigation ◽  
Major Influence ◽  
Small Scale ◽  
Highly Efficient ◽  
Strong Interest ◽  
Aerial Vehicles ◽  
Inflow Conditions ◽  
Fixed Pitch

A strong interest in highly-efficient, small-scale propeller configurations can be recognized, especially due to the currently growing number of and usage possibilities for unmanned aerial vehicles (UAVs). Although a variety of different propulsion concepts already exist on the market or are discussed in the literature, there is still a demand for a systematic investigation to compare such configurations, in particular, small-scale propellers with a fixed pitch, which are analyzed in this work. Therefore, different configurations of small-scale propellers with a fixed pitch are analyzed in this paper. They were operated as isolated single propellers and as ducted propellers in a cylindrical wing. Furthermore, due to their flight envelope, UAVs are likely to operate at highly inclined inflow conditions and even under reverse inflow. These non-axial inflow conditions have a major influence on the flow field around a propeller. In order to investigate this influence, all analyses were performed at a range of inflow angles in relation to the propeller axis from αdisc=0° to 180°.

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.

Numerical Simulation of the Aerodynamic Performance of a H-Type Wind Turbine during Self-Starting

2014 ◽  
Vol 529 ◽  
pp. 296-302 ◽  
Author(s):  
Wei Zuo ◽  
Shun Kang
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Pitch Angle ◽  
Turbulence Modeling ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Time Dependent ◽  
Two Dimensional ◽  
Vertical Axis Wind Turbine ◽  
Sst Turbulence Model

The aerodynamic performance and the bypass flow field of a vertical axis wind turbine under self-starting are investigated using CFD simulations in this paper. The influence of pitch angle variations on the performance of the wind turbine during self-starting is presented. A two-dimensional model of the wind turbine with three blades is employed. A commercial software FlowVision is employed in this paper, which uses dynamic Cartesian grid. The SST turbulence model is used for turbulence modeling, which assumes the flow full turbulent. Based on the comparison between the computed time-dependent variations of the rotation speed with the experimental data, the time-dependent variations of the torque are presented. The characteristics of self-starting of the wind turbine are analyzed with the pitch angle of 0o、-2oand 2o. The influence of pitch angle variations on two-dimensional unsteady viscous flow field through velocity contours is discussed in detail.

scholarly journals Numerical Analysis of Wind Turbine Airfoil Aerodynamic Performance with Leading Edge Bump

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Majid Asli ◽  
Behnam Mashhadi Gholamali ◽  
Abolghasem Mesgarpour Tousi
Keyword(s):  
Wind Turbine ◽  
Control Method ◽  
Flow Behavior ◽  
Renewable Energy Sources ◽  
Lift Coefficient ◽  
Turbine Blades ◽  
Vortex Generator ◽  
Leading Edge ◽  
Suction Side ◽  
Aerodynamic Performance

Aerodynamic performance improvement of wind turbine blade is the key process to improve wind turbine performance in electricity generated and energy conversion in renewable energy sources concept. The flow behavior on wind turbine blades profile and the relevant phenomena like stall can be improved by some modifications. In the present paper, Humpback Whales flippers leading edge protuberances model as a novel passive stall control method was investigated on S809 as a thick airfoil. The airfoil was numerically analyzed by CFD method in Reynolds number of 106and aerodynamic coefficients in static angle of attacks were validated with the experimental data reported by Somers in NREL. Therefore, computational results for modified airfoil with sinusoidal wavy leading edge were presented. The results revealed that, at low angles of attacks before the stall region, lift coefficient decreases slightly rather than baseline model. However, the modified airfoil has a smooth stall trend while baseline airfoil lift coefficient decreases sharply due to the separation which occurred on suction side. According to the flow physics over the airfoils, leading edge bumps act as vortex generator so vortices containing high level of momentum make the flow remain attached to the surface of the airfoil at high angle of attack and prevent it from having a deep stall.

Prediction of Aerodynamic Noise Radiated From a Vertical-Axis Wind Turbine

2003 ◽  
Author(s):  
Akiyoshi Iida ◽  
Akisato Mizuno ◽  
Kyoji Kamemoto
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Sound Source ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Low Noise ◽  
Aerodynamic Noise ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine

Unsteady flow field and flow induced noise of vertical axis wind turbine are numerically investigated. The flow field is numerically calculated by the vortex method with core-spreading model. This simulation obtains aerodynamic performance and aerodynamic forces. Aerodynamic noise is also simulated by using Ffowcs Williams-Hawkings equation with compact body and low-Mach number assumptions. Tip speed of rotor blades are not so high, then the contribution of the moving sound source is smaller than that of the dipole sound source. Since the maximum power coefficient of VAWT can be obtained at lower tip-speed ratio compared to the conventional, horizontal axis wind turbines, the aerodynamic noise from vertical axis wind turbine is smaller than that of the conventional wind turbines at the same aerodynamic performance. This result indicates that the vertical axis wind turbines are useful to develop low-noise wind turbines.

scholarly journals Design of Wind Turbine Blade with Thick Airfoils and Flatback and its Aerodynamic Characteristic

2015 ◽  
Vol 9 (1) ◽  
pp. 910-915 ◽  
Author(s):  
Lijun Xu ◽  
Lei Xu ◽  
Lei Zhang ◽  
Ke Yang
Keyword(s):  
Wind Turbine ◽  
Power Output ◽  
Aerodynamic Characteristic ◽  
Aerodynamic Performance ◽  
Parameter Design ◽  
Speed Ratio ◽  
Original Design ◽  
Tip Speed Ratio ◽  
Blade Tip ◽  
The Relationship

large-scaled blade has posed many problems related to design and production. After introducing the features of blade with thick airfoils and flatback, based on relevant parameters of Huaren 100 kW wind turbine, the paper designed blade with thick airfoils and flatback, introduced blade parameter design, and analyzed the aerodynamic performance of blades using GH bladed software, obtaining the relationship between power output of wind turbine with blade tip speed ratio Cp. Furthermore, it analyzed the aerodynamic performance of original design blades, modified blades and Huaren 100 kW blades, and assessed the aerodynamic performance of modified blade.

Compressible Simulation of Flow and Sound Around a Small Axial-Flow Fan With Flow Through Casing Slits

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Hiroshi Yokoyama ◽  
Katsutake Minowa ◽  
Kohei Orito ◽  
Masahito Nishikawara ◽  
Hideki Yanada
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Aerodynamic Performance ◽  
Design Flow ◽  
Low Flow ◽  
Axial Fan ◽  
Flow Rates ◽  
Blade Tip ◽  
Flow Through ◽  
Design Flow Rate

Abstract Small axial fans are used for cooling electronic equipment and are often installed in a casing with various slits. Direct aeroacoustic simulations and experiments were performed with different casing opening ratios to clarify the effects of the flow through the casing slits on the flow field and acoustic radiation around a small axial fan. Both the predicted and measured results show that aerodynamic performance deteriorates at and near the design flow rate and is higher at low flow rates by completely closing the casing slits compared with the fan in the casing with slits. The predicted flow field shows that the vortical structures in the tip vortices are spread by the suppression of flow through the slits at the design flow rate, leading to the intensification of turbulence in the blade wake. Moreover, the pressure fluctuations on the blade surface are intensified, which increases the aerodynamic sound pressure level. The suppression of the outflow of pressurized air through the downstream part of the slits enhances the aerodynamic performance at low flow rates. Also, the predicted surface streamline at the design flow rate shows that air flows along the blade tip for the fan with slits, whereas the flow toward the blade tip appears for the fan without slits. As a result, the pressure distributions on the blade and the torque exerted on the fan blade are affected by the opening ratio of slits.

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