The effects of aerofoil profile modification on a vertical axis wind turbine performance

Ismail, Farhad; Vijayaraghavan, Krishna

doi:10.1016/j.energy.2014.11.034

Cited by 129 publications

(51 citation statements)

References 19 publications

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“…The tangential force and the normal force for the blade are F T and F N , respectively. According to the pressure of each tap, F T and F N can be expressed as: According to Equation (9), the tangential force F T can be calculated. And then, the torque of the single blade can be calculated from Equation (4).…”

Section: Methodsmentioning

confidence: 99%

“…Currently, the large-type HAWT is very popular, but it is mainly installed in mountains, grasslands and oceans, where the infrastructure costs are very high. Moreover, there is an inevitable transmission loss of power because the wind turbines are far away from the power demand centers [8][9][10]. Straight-bladed vertical axis wind turbines (Sb-VAWTs) have been favored by global researchers due to their low production cost and insensitivity to high turbulence intensity in cities [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Blade Pitch Angle on the Aerodynamic Characteristics of a Straight-bladed Vertical Axis Wind Turbine Based on Experiments and Simulations

et al. 2018

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Abstract:The blade pitch angle has a significant influence on the aerodynamic characteristics of horizontal axis wind turbines. However, few research results have revealed its impact on the straight-bladed vertical axis wind turbine (Sb-VAWT). In this paper, wind tunnel experiments and CFD simulations were performed at the Sb-VAWT to investigate the effect of different blade pitch angles on the pressure distribution on the blade surface, the torque coefficient, and the power coefficient. In this study, the airfoil type was NACA0021 with two blades. The Sb-VAWT had a rotor radius of 1.0 m with a spanwise length of 1.2 m. The simulations were based on the k-ω Shear Stress Transport (SST) turbulence model and the wind tunnel experiments were carried out using a high-speed multiport pressure device. As a result, it was found that the maximum pressure difference on the blade surface was obtained at the blade pitch angle of β = 6 • in the upstream region. However, the maximum pressure coefficient was shown at the blade pitch angle of β = 8 • in the downstream region. The torque coefficient acting on a single blade reached its maximum value at the blade pitch angle of β = 6 • . As the tip speed ratio increased, the power coefficient became higher and reached the optimum level. Subsequently, further increase of the tip speed ratio only led to a quick reversion of the power coefficient. In addition, the results from CFD simulations had also a good agreement with the results from the wind tunnel experiments. As a result, the blade pitch angle did not have a significant influence on the aerodynamic characteristics of the Sb-VAWT.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Blade Pitch Angle on the Aerodynamic Characteristics of a Straight-bladed Vertical Axis Wind Turbine Based on Experiments and Simulations

et al. 2018

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“…They can be implemented together with a plasma actuator at the airfoil leading edge [35], or the plasma actuator can be implemented at the Gurney flap [81]. In addition to these, Gurney flaps have been used together with dimples [82], or with a trailing edge flap [83]. The most recent review of the Gurney flap was published by Wang et al [80].…”

Section: Gurney Flaps (Classification: Passive Geometric)mentioning

confidence: 99%

“…Better lift augmentation at higher Re [82] 2015 Gurney flap 2%c 255,000; 360,000 35-40% increase in tangential force [84] 2015 Gurney flap Axial pump 0.7-1.4%c 690,000 25% increase in pump head, widened operating range, decreased efficiency [59] 2014 Microtab Wind turbine 0.5-1.2%c 1,000,000 Increased lift and drag [88] 2014 Gurney flap 2%c 1,000,000 Lift augmentation, vibration control [86] 2013 Gurney flap 1.04-2.38%c 1,000,000 Effect on max. lift coefficient depends on airfoil shape [89] 2012 Gurney flap Centrifugal fan 15.9%b 2 30,000-82,000 Pressure ratio and operating range improved at Re < 69,000 [81] 2012 Gurney flap 3-7%c 20,000-35,000 Lift augmentation [90] 2011 Gurney flap Axial fan 10, 20, 30%c < 100,000 Max 18% increase in efficiency with q v,max [83] 2011 Gurney flap 0.7-6%c 254,000 Lift and drag augmentation [91] 2011 Gurney flap 1-6%c 105,000 Wake vortex control [92] 2011 Gurney flap 1.5%c 2,100,000 Vibration reduction [93] 2010 Jet-flap LPT cascade 25,000-200,000 12.5% reduction in solidity [94] 2010 Gurney flap LPT cascade 0.5-3%c 25,000-200,000 12.5% reduction in solidity [8] 2010 Microtab Wind turbine 1-1.5%c 460,000 Max 37% increase in lift [35] 2010 Gurney flap 3000-20,000 Lift augmentation [95] 2010 Gurney flap 40,000-80,000 Lift augmentation [96] 2003 Gurney flap Turbine cascade 0.6-2.7%c 28,000-167,000 Max 9% increase in lift force [85] 2000 Gurney flap 0.5-2%c 1,000,000 Increased lift and drag Outcome: Lift augmentation…”

Section: Gurney Flaps (Classification: Passive Geometric)mentioning

confidence: 99%

“…Dimples ( Figure 9) are affordable, robust, retrofittable, and manufacturable [65]. Despite the advantages of dimples, with exception of the investigations of Zhao et al [155] and Ismail and Vijayaraghavan [82], they have not recently been employed in turbomachinery applications. Zhao et al [155] found that dimples located at 30-60% of the chord length reduced the total pressure losses more than dimples located closer to the trailing edge.…”

Section: Turbulence and Vortex Generators (Classification: Passive Gmentioning

confidence: 99%

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Flow Control Methods and Their Applicability in Low-Reynolds-Number Centrifugal Compressors—A Review

Tiainen

Grönman

Jaatinen-Värri

et al. 2017

IJTPP

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Abstract:The decrease in the performance of centrifugal compressors operating at low Reynolds numbers (e.g., unmanned aerial vehicles at high altitudes or small turbomachines) can reach 10% due to increased friction. The purposes of this review are to represent the state-of-the-art of the active and passive flow control methods used to improve performance and/or widen the operating range in numerous engineering applications, and to investigate their applicability in low-Reynolds-number centrifugal compressors. The applicable method should increase performance by reducing drag, increasing blade loading, or reducing tip leakage. Based on the aerodynamic and structural demands, passive methods like riblets, squealers, winglets and grooves could be beneficial; however, the drawbacks of these approaches are that their performance depends on the operating conditions and the effect might be negative at higher Reynolds numbers. The flow control method, which would reduce the boundary layer thickness and reduce wake, could have a beneficial impact on the performance of a low-Reynolds-number compressor in the entire operating range, but none of the methods represented in this review fully fulfil this objective.

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Flow characteristics and dynamic responses of a parked straight‐bladed vertical axis wind turbine

Kuang

Chen

et al. 2019

Energy Science & Engineering

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With the development of urbanization and the application of renewable energy, wind turbine is becoming an important approach for wind energy reservation and utilization. This study provides a numerical investigation on understanding the surface pressure distribution, flow characteristics and dynamic responses of a parked straight‐bladed vertical axis wind turbine (VAWT), which is helpful for its design. Together with the two‐way coupling method between simulation platforms such as STAR‐CCM+ and ABAQUS, the SST k‐ω turbulence model is used to obtain the surface pressure and surrounding flow of the VAWT, and the finite element method is used to obtain the dynamic responses of its structural components. The results show that the contours of the pressure distribution on the windward surface of the VAWT are similar even under a few different conditions, and the deformation of the VAWT can lead to changes in surface pressure; the turbulent flow characteristics and the wake effect become more obvious as the wind velocity increases; the blades and support arms of the VAWT need to be reinforced during the design, and the effect of the parked condition on the dynamic responses of the VAWT can be neglected. The two‐way coupling method as well as the numerical simulation results is expected to provide references for the design of VAWTs subjected to coming wind action.

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The effects of aerofoil profile modification on a vertical axis wind turbine performance

Cited by 129 publications

References 19 publications

Effect of Blade Pitch Angle on the Aerodynamic Characteristics of a Straight-bladed Vertical Axis Wind Turbine Based on Experiments and Simulations

Effect of Blade Pitch Angle on the Aerodynamic Characteristics of a Straight-bladed Vertical Axis Wind Turbine Based on Experiments and Simulations

Flow Control Methods and Their Applicability in Low-Reynolds-Number Centrifugal Compressors—A Review

Flow characteristics and dynamic responses of a parked straight‐bladed vertical axis wind turbine

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