Submerged Boundary Layer Control Channels for Wind Turbine Blades
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Solution Overview
Problem
Existing wind turbine blades face issues with flow separation due to adverse pressure gradients, leading to increased drag and reduced lift, and existing vortex generators are either inefficient or prone to damage during transport.
Innovation Solution
The integration of submerged channels with merging sub-channels in the wind turbine blade surface, generating vortices that pull the boundary layer towards the surface, delaying or preventing flow separation and enhancing lift and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vortex generators are mounted on the surface of the wind turbine blade to delay or prevent flow separation, then flow separation is delayed or prevented, but the drag increases and the vortex generators are prone to break off during transport
Solution Approach 1:
The invention extracts the vortex generation function from surface-mounted protruding elements and relocates it to submerged channels embedded within the blade surface. The channels contain oblique walls that generate vortices internally, eliminating the need for external vortex generators that increase drag and are susceptible to damage during transport.
Solution Approach 2:
The submerged channels act as intermediaries that generate vortices through internal oblique walls rather than relying on external protruding elements. These channels are embedded within the blade surface, serving as a protective intermediary structure that prevents flow separation while avoiding the drag and fragility issues of surface-mounted vortex generators.
2Reliability
If vortex generators are mounted on the surface of the wind turbine blade to delay or prevent flow separation, then flow separation is delayed or prevented, but the vortex generators break off during transport
Solution Approach 1:
The invention extracts the vortex generation function from fragile surface-mounted protruding elements and relocates it to robust submerged channels embedded within the blade surface. The channels contain oblique walls that generate vortices internally, eliminating the need for external vortex generators that are susceptible to damage during transport.
Solution Approach 2:
The vortex-generating oblique walls are nested within the submerged channels that are themselves embedded in the blade surface. This nested structure protects the vortex-generating elements within the robust blade structure, preventing them from breaking off during transport while maintaining their flow separation prevention function.
3Shape
If the boundary layer is subjected to adverse pressure gradients due to the profile of the flow control surface, then the boundary layer is retarded, but flow separation occurs causing increased drag and reduced lift
Solution Approach 1:
The invention uses fluid dynamics principles by generating vortices through oblique walls within submerged channels. These vortices actively manipulate the boundary layer flow, creating rotational motion that prevents flow separation caused by adverse pressure gradients, thereby reducing drag and maintaining lift.
Solution Approach 2:
The invention changes the flow parameters by generating vortices that alter the boundary layer's velocity profile and pressure distribution. The vortices create favorable pressure gradients that counteract the adverse pressure gradients, preventing flow separation and maintaining attached flow over the blade surface.
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 solution effectively delays or prevents flow separation, increasing the overall lift and efficiency of the wind turbine blade by energizing the boundary layer with vortices, while being robust enough to withstand transport without damage.
Implementation Method 1
the two crossing sub-channels each direct a separate flow having a first velocity and second velocity direction, respectively, and due to the different velocity directions of these two oncoming flows vortices are generated at the point of crossing
Implementation Method 2
Such vortices will pull the boundary layer towards the flow control surface and energises the boundary layer, thereby delaying flow separation or preventing it entirely
Data Source
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AI summary
A wind turbine blade having a longitudinal direction with a root end and a tip end as well as a chord extending in a transverse direction between a leading edge and a trail- ing edge is described. The blade comprises a flow control surface with a suction side and a pressure side. A number of boundary layer control means is formed in the flow control surface. The boundary layer control means include a channel submerged in the flow control surface with a first end facing towards the leading edge and a second end facing towards the trailing edge of the blade. The channel further comprises a bottom surface extending from the first end to the second end. The channel at the first end comprises a first channel zone comprising a first sub-channel having a first cross- sectional area and a second sub-channel having a second cross-sectional area, the first sub-channel and the second sub-channel crossing each other at a point of crossing.