Wind Turbine Rotor Blade Dual Vortex Generator Rows
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Solution Overview
Problem
Wind turbine rotor blades face challenges in achieving optimal aerodynamic efficiency due to flow separation issues, particularly in regions with strong curvature, where existing vortex generator configurations may increase drag without adequately preventing separation.
Innovation Solution
The wind turbine rotor blade incorporates two rows of vortex generators, with the first row positioned closer to the leading edge and featuring two adjacent vortex generators with symmetric fins. The second row, positioned further back, includes a second fin with its trailing end closer to the centre line, strategically placed within a defined area to strengthen the vortex generated by the first row, thereby reducing flow separation and drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vortex generators are placed on the blade surface to counteract flow separation, then flow separation is reduced and lift is increased, but drag is increased
Solution Approach 1:
The vortex generator system is segmented into two rows with different configurations. The first row contains two adjacent vortex generators with symmetric fins, while the second row contains a single vortex generator with asymmetric fin positioning. This segmentation allows each row to perform different functions: the first row generates the primary vortex to prevent flow separation, while the second row strengthens the vortex with reduced drag impact through its asymmetric configuration and specific positioning within the vortex core area.
Solution Approach 2:
The invention applies local quality by positioning the second fin of the second row within a specifically defined area relative to the first row's vortex generators. The fin's trailing end is positioned at a spanwise distance x from the centre line that falls within calculated limits based on the distances D and d. This localized positioning ensures the second fin interacts with the vortex core at the optimal location to strengthen the vortex effect where it is most needed, while minimizing unnecessary drag from excessive fin size or mispositioning.
2Reliability
If vortex generators are positioned just before the expected flow separation line, then flow separation is effectively prevented, but the complexity of precise positioning increases
Solution Approach 1:
The invention implements preliminary action by positioning the second row of vortex generators downstream of the first row, within the vortex generation area. The second fin is positioned at a chordwise distance c from the trailing end of the first fin, ensuring it acts within the developing vortex field. This preliminary positioning allows the second fin to strengthen the vortex as it develops, rather than requiring precise positioning exactly at the separation point, thereby reducing positioning complexity while maintaining effectiveness.
Solution Approach 2:
The invention uses parameter changes by defining the position of the second fin based on calculated spanwise distance limits (xu and xL) that are functions of the geometric parameters D and d. These parameters are determined based on the vortex generator configuration and spacing, allowing the system to adapt to different blade designs while maintaining optimal positioning. This parametric approach simplifies the complexity by providing a systematic method rather than requiring fixed precise coordinates.
3Reliability
If larger vortex generators are used to strengthen the vortex, then flow separation is better prevented, but drag increases and structural requirements are compromised
Solution Approach 1:
The invention applies partial action by using a second fin that is smaller and positioned to provide just enough additional vortex strengthening to achieve the desired flow separation prevention. Rather than using large vortex generators that would excessively increase drag, the second fin provides a moderate strengthening effect through its strategic positioning within the vortex core area. This partial action is sufficient to achieve the reliability goal while minimizing the harmful drag effect.
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
This configuration enhances aerodynamic efficiency by minimizing flow separation while maintaining lower additional drag compared to traditional placements of vortex generators, thus optimizing energy capture from wind.
Implementation Method 1
the vortex generators are positioned obliquely, so that they have an angle of attack with respect to the local airflow, in order to create a vortex which draws energetic, rapidly moving outside air into the slow-moving boundary layer
Implementation Method 2
draws energetic, rapidly moving outside air into the slow-moving boundary layer in contact with the blade surface
Implementation Method 3
Vortex generators are used to trigger the transition from laminar flow to turbulent flow
Implementation Method 4
A turbulent boundary layer is less likely to separate than a laminar one
Data Source
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AI summary
A wind turbine rotor blade comprising • a first row of vortex generators comprising two adjacent vortex generators each having a longitudinal axis and two first fins having trailing ends arranged in a distance d from each other, wherein the two longitudinal axes define a centre line, • a second row of vortex generators comprising a second fin having a trailing end arranged closer to the centre line than a leading end of the second fin, • wherein the second fin is positioned with reference to the first fin that is arranged on the same side of the centre line as the second fin such that the trailing end of the second fin is arranged in a chordwise distance c from the trailing end of that first fin, • wherein a distance x of the trailing end of the second fin from the centre line is within a certain defined range.