Aerodynamics of leading-edge protection tapes for wind turbine blades

2020 ◽  
pp. 0309524X2097544
Author(s):  
Desirae Major ◽  
Jose Palacios ◽  
Mark Maughmer ◽  
Sven Schmitz
Keyword(s):  
Boundary Layer ◽  
Wind Turbine ◽  
Numerical Models ◽  
Turbine Blades ◽  
Leading Edge ◽  
Boundary Layer Transition ◽  
Wind Turbine Blades ◽  
Layer Transition ◽  
Tape Edge ◽  
The Impact

This paper presents results of a comparative study on the effect of standard and tapered leading-edge protection (LEP) tapes on the annual energy production (AEP) of a utility-scale 1.5 MW wind turbine. Numerical models are developed in STAR-CCM+ to estimate the impact of LEP tapes on lift and drag coefficients of an NACA 64-618 airfoil operating at Re = 3 × 106. Experimental drag coefficient data are collected for LEP tapes applied to the tip-section of a de-commissioned wind turbine blade for numerical validation. The objective is to determine the physical mechanisms responsible for the aerodynamic degradation observed with standard LEP tapes, and to design a tapered LEP tape that reduces the associated adverse impact on AEP. An in-house wind turbine design and analysis code, XTurb-PSU, is used to estimate AEP using airfoil data obtained by STAR-CCM+. For standard LEP tapes, laminar-to-turbulent boundary-layer transition occurs at the LEP tape edge, resulting in AEP losses of 2%–3%. Comparable tapered LEP tapes can be designed to suppress boundary-layer transition for backward-facing step heights below a critical value such that associated impact on AEP is negligible.

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

2020 ◽  
Vol 5 (3) ◽  
pp. 977-981 ◽  
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.

Application of Tubercles in Wind Turbine Blades: A Review

2017 ◽  
Vol 867 ◽  
pp. 254-260 ◽  
Author(s):  
Vivek V. Kumar ◽  
Dilip A. Shah
Keyword(s):  
Boundary Layer ◽  
Wind Turbine ◽  
Fossil Fuels ◽  
Turbine Blades ◽  
Leading Edge ◽  
Electrical Energy ◽  
Humpback Whale ◽  
Wind Turbine Blades ◽  
Horizontal Axis Wind Turbine ◽  
Turbulent Fluid Flow

Due to the rapid depletion of conventional energy resources like fossil fuels and their harmful effects on the environment, there is an urgent need to seek alternative and sustainable energy sources. Wind energy is considered as one of the efficient source of energy which can be converted to useful form of energy like electrical energy. Though the field of wind engineering has developed in the recent era there is still scope for improvement in the effective utilization of energy. Energy efficiency in wind turbine is largely determined by the aerodynamics of the turbine blades and the characteristics of the turbulent fluid flow. The objective of this paper is to have a review on the improvement of Horizontal Axis Wind Turbine (HAWT) blade design by incorporating biomimetics into blades. Biomimetics is the field of science in which we adapt designs from nature to solve modern problems. The morphology of the wing-like flipper of the humpback whale (Megaptera novaeangliae) has potential for aerodynamic applications. Instead of straight leading edges like that of conventional hydrofoils, the humpback whale flipper has a number of sinusoidal rounded bumps, called tubercles arranged periodically along the leading edge. The presence of tubercles modifies the flow over the blade surface, creating vortices between the tubercles. These vortices interact with the flow over the tubercle and accelerate that flow, helping to maintain a partially attached boundary layer. This aerodynamic effect can delay stall to higher angles of attack, increase lift and reduce drag compared to the post-stall condition of conventional airfoils. The modified airfoil is characterized by a superior lift/drag ratio (L/D ratio) due to greater boundary layer attachment from vortices energizing the boundary layer.

scholarly journals Modelling Rain Drop Impact of Offshore Wind Turbine Blades

2012 ◽  
Author(s):  
M. H. Keegan ◽  
D. H. Nash ◽  
M. M. Stack
Keyword(s):  
Wind Turbine ◽  
Impact Damage ◽  
Turbine Blades ◽  
Leading Edge ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wind Turbine Blades ◽  
Erosion Testing ◽  
Software Modelling ◽  
The Impact

The effects of rain and hail erosion and impact damage on the leading edge of offshore wind turbine blades have been investigated. A literature review was conducted to establish the effects of exposure to these conditions and also to investigate the liquid impact phenomena and their implications for leading edge materials. The role of Explicit Dynamics software modelling in simulating impact events was then also established. Initial rain impact modelling is then discussed with the results showing good agreement with theoretical predictions both numerically and with respect to the temporal and spatial development of the impact event. Future development of the rain model and a proposed hail model are then detailed. Planned rain impact and erosion testing work is addressed which will be used to validate, inform and compliment the ongoing modelling efforts.

Effects of Leading-Edge Protection Tape on Wind Turbine Blade Performance

2012 ◽  
Vol 36 (5) ◽  
pp. 525-534 ◽  
Author(s):  
Agrim Sareen ◽  
Chinmay A. Sapre ◽  
Michael S. Selig
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Leading Edge ◽  
Reynolds Numbers ◽  
Lower Surface ◽  
Wind Turbine Blades ◽  
Potential Benefits ◽  
Wind Turbine Airfoil ◽  
Turbine Airfoils ◽  
The Impact

This paper presents results of a study to investigate the impact of using wind protection tape (WPT) to protect the leading edge of wind turbine airfoils from erosion. The tests were conducted on the DU 96-W-180 wind turbine airfoil at three Reynolds numbers between 1 and 1.85 million and angles of attack spanning the low drag range of the airfoil. Tests were run by varying the chordwise extent of the wind protection tape on the upper and lower surface in order to determine the relative impact of each configuration on the aerodynamics of the airfoil. The objective was to assess the performance losses due to the wind protection tape and compare them with losses due to leading-edge erosion in order to determine the potential benefits of using such tape to protect wind turbine blades. Results showed that the application of wind protection tape caused a drag increase of 5–15% for the various configurations tested and was significantly less detrimental to airfoil performance than leading edge erosion that could otherwise occur.

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

2020 ◽  
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 solid or liquid phase. A reduction of the wind turbine blades’ tip speed during severe 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 vertical pointing radar that measures rain in different heights with a sufficient high spatio-temporal resolution can nowcast rain for an erosion-safe mode.

scholarly journals Selection and impact of leading edge on boundary layer transition

2020 ◽  
Author(s):  
Dinesh Devraj Bhatia ◽  
Guangjun Yang ◽  
Guangning Li ◽  
Jian Wang
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Flow Structure ◽  
Leading Edge ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Stagnation Region ◽  
Leading Edges ◽  
The Impact ◽  
Selection Of

Abstract The choice of leading edge aspect ratio (AR) plays a crucial role when planning boundary layer experimental wind tunnel tests on a flat plate. Poor selection of the leading-edge profile hampers the effectiveness of the experiment and increases testing costs associated with interchanging of leading edges to attain accurate results. Thus, the appropriate selection of the leading edge is a very crucial part of the wind tunnel experimental process. The authors, in this paper, argue that the curvature of the leading edge and thus the AR are of paramount importance to attain accurate results from wind tunnel testing. In this paper, the authors have tested 7 different elliptical leading edges and compared their performance with an ideal leading edge with zero thickness. Experimental and computational has been presented for leading edges ranging from AR6 to AR20. Results were evaluated for boundary layer transition onset location and it was found that AR20 has the least influence on the flow structure when compared the ideal leading edge. A study of the flow structure at the stagnation point indicates an increase in adverse pressure gradient with an increase in the AR but also a decrease in the size of the stagnation region. The presence of a higher AR leading edge reduces the turbulent spot production rate which is one of the primary causes of boundary layer transition. The authors have presented a correlation which makes it easier for aerodynamicists to quantify the impact of the leading-edge AR on transition. A case is also presented to compare the relative performance of a wedge and the higher AR leading edge which gives potential researchers the choice between an elliptical or a wedge-shaped leading edge.

Leading edge erosion of wind turbine blades: Understanding, prevention and protection

2021 ◽  
Vol 169 ◽  
pp. 953-969
Author(s):  
Leon Mishnaevsky ◽  
Charlotte Bay Hasager ◽  
Christian Bak ◽  
Anna-Maria Tilg ◽  
Jakob I. Bech ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Leading Edge ◽  
Wind Turbine Blades

Experimental investigations of flow over NACA airfoils 0021 and 4412 of wind turbine blades with and without Tubercles

2021 ◽  
pp. 0309524X2110071
Author(s):  
Usman Butt ◽  
Shafqat Hussain ◽  
Stephan Schacht ◽  
Uwe Ritschel
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Wind Turbine ◽  
Critical Region ◽  
Lift Coefficient ◽  
Turbine Blades ◽  
Leading Edge ◽  
Reynolds Numbers ◽  
Experimental Investigations ◽  
Wind Turbine Blades

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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