Aerodynamic Sensitivity Analysis for a Wind Turbine Airfoil in an Air-Particle Two-Phase Flow

Guo, Tong; Jin, Junjun; Lu, Zhiliang; Zhou, Di; Wang, Tongguang

doi:10.3390/app9183909

Cited by 6 publications

(13 citation statements)

References 22 publications

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“…Three loops also have little difference, except for the inclined angle. However, for S809 airfoil, according to the analysis of the steady case by Guo et al [34], the lift coefficient stops linearly increasing and decreases slightly near the angle of attack of 8 • , due to the forward movement of the boundary-layer separation point from the trailing edge, which is called the light stall. During the following stroke, the lift coefficient increases again and drops into deep stall at an angle greater than 16 • .…”

Section: Hysteresis Loops At Different Reduced Frequenciesmentioning

confidence: 99%

“…In her study, it is found that the effect of particles on dynamic stall of NACA 0012 airfoil is small and negligible at a common particle concentration. Guo et al [34] compared the effect of particles on aerodynamic performance of aircraft wind turbine airfoils. They found when the NACA0012 airfoil runs in a steady air-particle flow, with a particle mass concentration of 1%, lift coefficient penalties are about 0.2% and 1% at the operating angles of attack of the aircraft and the wind turbine, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Comparative Study of Dynamic Stall between an Aircraft Airfoil and a Wind Turbine Airfoil in an Air–Particle Flow

Jin

Guo

et al. 2021

Applied Sciences

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Dynamic stall in clean air flow has been well studied, but its exploration in air–particle (air–raindrop or air–sand) flow is still lacking. The aerodynamic performance loss of aircraft (NACA0012) and wind turbine (S809) airfoils and their differences during the hysteresis loop at different pitching parameters are also poorly understood. As shown in this paper, the reduced frequency has little effect on the value of the maximum lift coefficient increment caused by particles, but a larger one can enhance the hysteresis effect and drag the angle of attack, at which the maximum increment is obtained, from the up stroke to the down stroke. The large lift coefficient increments of two airfoils and their difference also have a similar change trend with the reduced frequency. Compared to that of NACA0012 airfoil, the increments of S809 airfoil are obviously greater at three mean angles of attack, especially at 8°, which is the commonly used operating angle. In addition, the angle of attack, at which the maximum lift coefficient is obtained, can be significantly changed by particles in two regions: one is under the effect of deep stall, the other is under the effect of light stall at a low, reduced frequency.

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Section: Hysteresis Loops At Different Reduced Frequenciesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparative Study of Dynamic Stall between an Aircraft Airfoil and a Wind Turbine Airfoil in an Air–Particle Flow

Jin

Guo

et al. 2021

Applied Sciences

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“…A similar sensitivity is the prerequisite to compare the aerodynamic change caused by other factors and the sensitivity of an airfoil can be obtained by the Reynolds number and angle of attack according to the results in our previous work [10]. Then, the formula (27) is transformed as

S t = \frac{Re}{18} \frac{ρ_{P}}{ρ_{a}} {((), \frac{D_{P}}{c})}^{2} .

…”

Section: Computational Model and Particle Parametersmentioning

confidence: 99%

Marking function of Stokes number on airfoils’ aerodynamic penalties in a gas–solid flow

Jin

Guo

et al. 2021

IET Renewable Power Gen

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This paper aims to employ the Stokes number to mark aerodynamic penalties of airfoils caused by particles, which is crucial to implement their scaling experiments in a gas‐solid flow. Each Stokes number is associated with a series of approximate aerodynamic penalties which are obtained at the same Reynolds number with different chord lengths. In the process, two phenomena which go against the mark are discussed and their mechanisms are revealed. The results show they occur at smaller and larger ranges of Stokes number, respectively. The effect of gravity is the leading cause and a larger chord length or diameter particle can strength its effect. The application scope of the mark, meanwhile, is ascertained. A chord length smaller than 1.5 m is advised at Re = 1.00 × 106 and those at other Reynolds numbers are also presented. As Stokes number decreases from 3, the aerodynamic penalty increases exponentially first at the advised chord length and reaches up to their peak values at the Stokes number of 0.050. In addition, the change of the aerodynamic penalty with Stokes number is dominated by the momentum exchange in the direction of gravity in the region between the particle injection plane and the airfoil.

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“…However, experimental approaches to the measurement of LS and transition onset (TO) points are both expensive and time consuming. Thus, as an alternative, computational fluid dynamics (CFD) approaches which use numerical modeling techniques, are more preferred for the accurate prediction of the aerodynamic performance of airfoils [19][20][21]. However, one of the major challenges in the accurate simulation of airfoil aerodynamics is to reproduce the transitional flow.…”

Section: Introductionmentioning

confidence: 99%

Characteristics and Effects of Laminar Separation Bubbles on NREL S809 Airfoil Using the γ - R e θ Transition Model

Rho

2020

Applied Sciences

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Understanding the characteristics and effects of the laminar separation bubbles (LSBs) is important in the aerodynamic design of wind turbine airfoils for maximizing wind turbine efficiency. In the present study, numerical simulations using the γ-Reθ transition model were performed to analyze the flow structure of LSBs around a 21% thick NREL S809 airfoil. The simulation results obtained from the γ-Reθ transition model and the standard k-ε model for the aerodynamic coefficients at various angles of attack (AoAs) were compared with the wind tunnel data acquired from the Delft University 1.8 m × 1.25 m low-turbulence wind tunnel. When the AoA increased, the bubble on the suction airfoil surface was found to move closer to the leading edge owing to an earlier laminar separation (LS). Furthermore, the transition onset (TO) points were shown to occur right after separation, thus causing an abrupt increase in turbulence intensity (TI) and forming different bubble extents with increasing AoAs. Consequently, the transition model-based approaches can provide a clear understanding of the characteristics and effects of the LSB on airfoil aerodynamic performance. The findings of this study can provide important insights into redesigning an airfoil with a reduced bubble length causing the improved aerodynamic performance.

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Aerodynamic Sensitivity Analysis for a Wind Turbine Airfoil in an Air-Particle Two-Phase Flow

Cited by 6 publications

References 22 publications

Comparative Study of Dynamic Stall between an Aircraft Airfoil and a Wind Turbine Airfoil in an Air–Particle Flow

Comparative Study of Dynamic Stall between an Aircraft Airfoil and a Wind Turbine Airfoil in an Air–Particle Flow

Marking function of Stokes number on airfoils’ aerodynamic penalties in a gas–solid flow

Characteristics and Effects of Laminar Separation Bubbles on NREL S809 Airfoil Using the γ - R e θ Transition Model

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