scholarly journals New airfoils for micro horizontal-axis wind turbines

2021 ◽  
Author(s):  
Manoj Kumar Chaudhary ◽  
◽  
S. Prakash ◽  
Keyword(s):  
Reynolds Number ◽  
Wind Turbines ◽  
Low Reynolds Number ◽  
Horizontal Axis ◽  
Speed Ratio ◽  
Maximum Output ◽  
Horizontal Axis Wind Turbine ◽  
Horizontal Axis Wind Turbines ◽  
Low Reynolds ◽  
Bem Theory

In this study, small horizontal-axis wind turbine blades operating at low wind speeds were optimized. An optimized blade design method based on blade element momentum (BEM) theory was used. The rotor radius of 0.2 m, 0.4 m and 0.6 m and blade geometry with single (W1 & W2) and multistage rotor (W3) was examined. MATLAB and XFoil programs were used to implement to BEM theory and devise a six novel airfoil (NAF-Series) suitable for application of small horizontal axis wind turbines at low Reynolds number. The experimental blades were developed using the 3D printing additive manufacturing technique. The new airfoils such as NAF3929, NAF4420, NAF4423, NAF4923, NAF4924, and NAF5024 were investigated using XFoil software at Reynolds numbers of 100,000. The investigation range included tip speed ratios from 3 to 10 and angle of attacks from 2° to 20°. These parameters were varied in MATLAB and XFoil software for optimization and investigation of the power coefficient, lift coefficient, drag coefficient and lift-to-drag ratio. The cut-in wind velocity of the single and multistage rotors was approximately 2.5 & 3 m/s respectively. The optimized tip speed ratio, axial displacement and angle of attack were 5.5, 0.08m & 6° respectively. The proposed NAF-Series airfoil blades exhibited higher aerodynamic performances and maximum output power than those with the base SG6043 and NACA4415 airfoil at low Reynolds number.

Design of a low Reynolds number airfoil for small horizontal axis wind turbines

2012 ◽  
Vol 42 ◽  
pp. 66-76 ◽  
Author(s):  
Ronit K. Singh ◽  
M. Rafiuddin Ahmed ◽  
Mohammad Asid Zullah ◽  
Young-Ho Lee
Keyword(s):  
Reynolds Number ◽  
Wind Turbines ◽  
Low Reynolds Number ◽  
Horizontal Axis ◽  
Horizontal Axis Wind Turbines ◽  
Low Reynolds ◽  
Low Reynolds Number Airfoil

scholarly journals Design and Fabrication of Small Horizontal axis wind Turbine Rotors at Low Reynolds Number

2019 ◽  
Vol 8 (12) ◽  
pp. 4454-4463 ◽  
Keyword(s):  
Reynolds Number ◽  
Wind Turbine ◽  
Low Reynolds Number ◽  
Angle Of Attack ◽  
Horizontal Axis ◽  
Speed Ratio ◽  
Horizontal Axis Wind Turbine ◽  
Tip Speed Ratio ◽  
Drag Ratio ◽  
Lift To Drag Ratio

This research paper presents a design and fabrication of 100 Watt small horizontal axis wind turbine with 0.24 m and 0.35 m rotor radius and tip speed ratio varies from 2 to 10 was designed and development for operated at low wind speed with Low Reynolds number. In this paper, a new airfoil profile was designed and developed, it’s denoted by MK115. The numerical and experimental analysis for 6 airfoils using Xfoil software was conducted with a view to evaluating the lift-to-drag ratio and angle of attack by means of the SD7024, SG6043, NACA2412, S1210, E213, and New Airfoil (MK115) tested. In simulation, new MK115 airfoil was the most convenient airfoil to start high energy production for low-wind applications, on the Reynolds number 25000, 50000, 75000, and 100000 in improved airfoil (MK115) tests an Open type wind tunnel. An Xfoil analysis to obtain further data on the flow characteristics was also conducted. (MK115) airfoil have CLmax of 0.92, 1.25, 1.69, 1.67 at Re=25k, 50k, 75k and 100k for an angle of attack is equal to 100 .A maximum lift to drag ratio (Cl/Cd) of 7,16,50,63 at Re=25k, 50k, 75k and 100k for New airfoil (MK115) at angle of attack (α) =40 , 40 , 80 , 80 . SG6043, NACA2412, E214, SD7034, S1210 and MK115 (New airfoil) have the Maximum Cp=0.37, 0.36, 0.4, 0.39, 0.44, and 0.44 at tip speed ratio (λ) =6 for Reynolds number is equal to 100000. MK115, Maximum Torque obtained 0.9744 Nm, 1.389 Nm and 2.4866 Nm at blade angle =0, 15 and 30 degrees respectively. Power coefficient (Cp) =0.51, 0.5, 0.46, and 0.4 at Rotor shaft angle=00 , 50 , 100 , and 150 respectively for the new airfoil results.

scholarly journals Wake Expansion and the Finite Blade Functions for Horizontal-Axis Wind Turbines

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7653
Author(s):  
David Wood
Keyword(s):  
Radial Velocity ◽  
Wind Turbines ◽  
Loss Factor ◽  
Axial Direction ◽  
Horizontal Axis ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
Constant Pitch ◽  
Horizontal Axis Wind Turbines ◽  
Blade Element

This paper considers the effect of wake expansion on the finite blade functions in blade element/momentum theory for horizontal-axis wind turbines. For any velocity component, the function is the ratio of the streamtube average to that at the blade elements. In most cases, the functions are set by the trailing vorticity only and Prandtl’s tip loss factor can be a reasonable approximation to the axial and circumferential functions at sufficiently high tip speed ratio. Nevertheless, important cases like coned or swept rotors or shrouded turbines involve more complex blade functions than provided by the tip loss factor or its recent modifications. Even in the presence of significant wake expansion, the functions derived from the exact solution for the flow due to constant pitch and radius helical vortices provide accurate estimates for the axial and circumferential blade functions. Modifying the vortex pitch in response to the expansion improves the accuracy of the latter. The modified functions are more accurate than the tip loss factor for the test cases at high tip speed ratio that are studied here. The radial velocity is important for expanding flow as it has the magnitude of the induced axial velocity near the edge of the rotor. It is shown that the resulting angle of the flow to the axial direction is small even with significant expansion, as long is the tip speed ratio is high. This means that blade element theory does not have account for the effective blade sweep due to the radial velocity. Further, the circumferential variation of the radial velocity is lower than of the other components.

Aerodynamic Design and Wind Tunnel Tests of Small-scale Horizontal-axis Wind Turbines for Low Tip Speed Ratio Applications

2022 ◽  
pp. 1-34
Author(s):  
Ojing Siram ◽  
Neha Kesharwani ◽  
Niranjan Sahoo ◽  
Ujjwal K. Saha
Keyword(s):  
Wind Tunnel ◽  
Wind Turbines ◽  
Pitch Angle ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Small Scale ◽  
Wind Tunnel Tests ◽  
Tip Speed Ratio ◽  
Horizontal Axis Wind Turbines

Abstract In recent times, the application of small-scale horizontal axis wind turbines (SHAWTs) has drawn interest in certain areas where the energy demand is minimal. These turbines, operating mostly at low Reynolds number (Re) and low tip speed ratio (λ) applications, can be used as stand-alone systems. The present study aims at the design, development, and testing of a series of SHAWT models. On the basis of aerodynamic characteristics, four SHAWT models viz., M1, M2, M3, and M4 composed of E216, SG6043, NACA63415, and NACA0012 airfoils, respectively have been developed. Initially, the rotors are designed through blade element momentum theory (BEMT), and their power coefficient have been evaluated. Thence, the developed rotors are tested in a low-speed wind tunnel to find their rotational frequency, power and power coefficient at design and off-design conditions. From BEMT analysis, M1 shows a maximum power coefficient (Cpmax) of 0.37 at λ = 2.5. The subsequent wind tunnel tests on M1, M2, M3, and M4 at 9 m/s show the Cpmax values to be 0.34, 0.30, 0.28, and 0.156, respectively. Thus, from the experiments, the M1 rotor is found to be favourable than the other three rotors, and its Cpmax value is found to be about 92% of BEMT prediction. Further, the effect of pitch angle (θp) on Cp of the model rotors is also examined, where M1 is found to produce a satisfactory performance within ±5° from the design pitch angle (θp, design).

Analysis on Aerodynamic Performance of Horizontal Axis Wind Turbine Based on Nonlinear Wake Model

2013 ◽  
Vol 448-453 ◽  
pp. 1716-1720
Author(s):  
Rui Yang ◽  
Jiu Xin Wang ◽  
Sheng Long Zhang
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Optimization Design ◽  
Aerodynamic Performance ◽  
Horizontal Axis ◽  
Wake Vortex ◽  
Horizontal Axis Wind Turbine ◽  
Horizontal Axis Wind Turbines ◽  
Wake Model ◽  
Induced Velocity

A computational method based on nonlinear wake model was established for horizontal axis wind turbines aerodynamic performance prediction. This method makes use of finite difference method to solve the integral differential equation of the model, the induced velocity of wake vortex can be calculated from equations and compared with the induced velocity of wake vortex in linear model. The comparison between the calculated results of wind turbine under axis flow condition, including tip vortex geometry and aerodynamic performance, and available experimental data shows that this method is suitable for wind turbine aerodynamic performance analysis. Finally, a series of numerical calculations were made to investigate the change of wake geometry and aerodynamic performance of the wind turbine when yawing and pitch angle increasing, which provide foundations for aerodynamic optimization design of horizontal axis wind turbines.

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