Numerical and experimental investigation on the effects of bumps over the leading edge of the micro wind turbine blades suitable for low wind regimes

Experimental investigations of wind turbine blades having NACA airfoils 0021 and 4412 with and without tubercles on the leading edge have been performed in a wind tunnel. It was found that the lift coefficient of the airfoil 0021 with tubercles was higher at Re = 1.2×105 and 1.69×105 in post critical region (at higher angle of attach) than airfoils without tubercles but this difference relatively diminished at higher Reynolds numbers and beyond indicating that there is no effect on the lift coefficients of airfoils with tubercles at higher Reynolds numbers whereas drag coefficient remains unchanged. It is noted that at Re = 1.69×105, the lift coefficient of airfoil without tubercles drops from 0.96 to 0.42 as the angle of attack increases from 15° to 20° which is about 56% and the corresponding values of lift coefficient for airfoil with tubercles are 0.86 and 0.7 at respective angles with18% drop.

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Review of Icing Effects on Wind Turbine in Cold Regions

E3S Web of Conferences ◽

10.1051/e3sconf/20187201007 ◽

2018 ◽

Vol 72 ◽

pp. 01007 ◽

Cited By ~ 2

Author(s):

Faizan Afzal ◽

Muhammad S. Virk

Keyword(s):

Wind Turbine ◽

Structural Integrity ◽

Turbine Blades ◽

Leading Edge ◽

Added Mass ◽

Cold Climate ◽

Ice Accretion ◽

Wind Turbine Blades ◽

Turbine Performance ◽

Ice Shedding

This paper describes a brief overview of main issues related to atmospheric ice accretion on wind turbines installed in cold climate region. Icing has significant effects on wind turbine performance particularly from aerodynamic and structural integrity perspective, as ice accumulates mainly on the leading edge of the blades that change its aerodynamic profile shape and effects its structural dynamics due to added mass effects of ice. This research aims to provide an overview and develop further understanding of the effects of atmospheric ice accretion on wind turbine blades. One of the operational challenges of the wind turbine blade operation in icing condition is also to overcome the process of ice shedding, which may happen due to vibrations or bending of the blades. Ice shedding is dangerous phenomenon, hazardous for equipment and personnel in the immediate area.

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Brief communication: Nowcasting of precipitation for leading-edge-erosion-safe mode

Wind Energy Science ◽

10.5194/wes-5-977-2020 ◽

2020 ◽

Vol 5 (3) ◽

pp. 977-981 ◽

Cited By ~ 1

Author(s):

Anna-Maria Tilg ◽

Charlotte Bay Hasager ◽

Hans-Jürgen Kirtzel ◽

Poul Hummelshøj

Keyword(s):

Liquid Phase ◽

Wind Turbine ◽

Turbine Blades ◽

Leading Edge ◽

Wind Turbine Blades ◽

Spatio Temporal ◽

The Impact ◽

Theoretical Considerations ◽

Mode A ◽

Precipitation Events

Abstract. Leading-edge erosion (LEE) of wind turbine blades is caused by the impact of hydrometeors, which appear in a solid or liquid phase. A reduction in the wind turbine blades' tip speed during defined precipitation events can mitigate LEE. To apply such an erosion-safe mode, a precipitation nowcast is required. Theoretical considerations indicate that the time a raindrop needs to fall to the ground is sufficient to reduce the tip speed. Furthermore, it is described that a compact, vertically pointing radar that measures rain at different heights with a sufficiently high spatio-temporal resolution can nowcast rain for an erosion-safe mode.

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