Two-Part Wind Turbine Rotor Blades with Localized Swirl Elements
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Solution Overview
Problem
Maximizing the yield of wind turbine rotor blades while addressing manufacturing, transport, and aerodynamic challenges, particularly flow separation and structural issues associated with separation points and swirl elements in two-part rotor blades.
Innovation Solution
Optimizing the position and design of swirl elements on two-part rotor blades by limiting the ratio of outer length to total length to less than 0.25, using vortex generators with specific geometries and materials, and adjusting the profile thickness to manage loads and flow separation effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rotor blades are made longer to maximize yield, then energy production increases, but manufacturing and transport challenges increase
Solution Approach 1:
The rotor blade is divided into two separate parts: an inner blade section and an outer blade section, joined at a separation point. This segmentation allows each section to be manufactured and transported independently, overcoming the limitations of transporting single-piece blades longer than 60 meters while maintaining the total blade length for maximum energy production
2Ease of manufacture
If a separation point is provided in two-part rotor blades, then transport is facilitated, but aerodynamic and structural challenges increase due to associated weight
Solution Approach 1:
The profile thickness is specifically optimized at the separation point location. The blade features increased relative thickness (profile thickness to profile length ratio) precisely at the separation point where structural loads are greatest, while other sections can use thinner profiles to reduce overall weight. This localized reinforcement minimizes the weight penalty of the separation point
3Reliability
If profiles with high relative thickness are used near the hub, then flow separation is reduced, but drag increases
Solution Approach 1:
The relative thickness of the airfoil profile is varied along the span of the rotor blade. Near the hub, profiles have higher relative thickness to prevent flow separation in the low-speed region. Further out along the blade where wind speed increases, the relative thickness is reduced to minimize drag. This gradient in profile thickness optimizes the balance between preventing flow separation and reducing drag losses
4Reliability
If swirl elements are added to delay flow separation, then aerodynamic performance improves, but drag increases
Solution Approach 1:
Swirl elements such as vortex generators are strategically placed only in specific regions where flow separation is most likely to occur, typically near the hub area. The swirl elements are not distributed uniformly along the entire blade, but rather concentrated in locations where they provide maximum benefit in delaying flow separation while minimizing their overall drag contribution
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the aerodynamic performance and structural integrity of large wind turbine rotors by reducing drag and flow separation, thereby improving energy efficiency and reducing manufacturing and transport complexities.
Implementation Method 1
the rotor blades have an aerodynamic profile that generates an aerodynamic force when exposed to the wind, which is ultimately converted to generate electrical power in the wind turbine
Implementation Method 2
Mounted on a wind turbine rotor, the rotor blades have an aerodynamic profile that generates an aerodynamic force when exposed to the wind
Implementation Method 3
it is known to arrange swirl elements, such as vortex generators, on the rotor blade near the hub. These elements are designed to introduce energy into the flow boundary layer and thus delay flow separation
Implementation Method 4
These elements are designed to introduce energy into the flow boundary layer and thus delay flow separation
Data Source
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AI summary
The invention relates to a rotor blade (108) of a rotor (106) for a wind turbine (100), and to an associated wind turbine (100), and to a method for optimising a wind turbine (100). Before being mounted on the wind turbine (100), the rotor blade (108) is divided into an inner blade section (132) and an outer blade section (134) at a separating point (130), the longitudinal direction (L) of the rotor blade (108) being defined from the root section to the blade tip. The rotor blade (108) has at least one turbulence element (140), the turbulence element (140) extending in the longitudinal direction (L) of the rotor blade (108). The distance between a start, pointing towards the root section (114), and an end, pointing towards the rotor blade tip (116), of the turbulence element (140) in the longitudinal direction (L) is referred to as the total length (Lges), and the distance between the separating point (130) and the outer end (142) of the turbulence element (140) is referred to as the outer length (Laußen), the ratio of the outer length (Laußen) to the total length (Lges) being less than 0.25.