Wind Turbine Blade Flow Guiding Device for Lift-Drag Optimization
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Solution Overview
Problem
Wind turbine blades face challenges in aerodynamic performance, particularly in the root and transition regions, leading to increased drag and reduced energy production, with existing solutions either increasing drag or not effectively enhancing lift-to-drag ratios.
Innovation Solution
A flow guiding device is integrated into the blade's pressure side, extending along the transition region, with a specific design that includes an inflow surface and end point configuration to generate airflow separation, increasing lift while managing drag, thereby improving the lift-to-drag ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the blade width in the transition region is increased to improve aerodynamic performance, then the lift is improved, but the drag increases due to larger surface area
Solution Approach 1:
The flow guiding device is divided into multiple elements arranged along the transition region, with each element having a specific height and spacing. This segmentation allows the device to guide flow effectively while minimizing overall drag compared to a single large structure.
Solution Approach 2:
The flow guiding device is specifically positioned in the transition region where flow separation naturally occurs, rather than uniformly across the entire blade. The device height and spacing are optimized for this specific region's aerodynamic characteristics, improving lift where needed while limiting drag increase.
2Power
If a flow guiding device is added to the blade to increase lift, then the aerodynamic performance is improved, but the device complexity increases
Solution Approach 1:
The flow guiding device elements are designed as thin, lightweight structures that can be integrated into the blade profile without adding significant mass or structural complexity. The elements follow the blade's contour and can be manufactured as thin-walled components.
Solution Approach 2:
The flow guiding device is applied only to the transition region of the blade where it is most needed, rather than the entire blade span. This partial application achieves the desired lift improvement while minimizing the added complexity and manufacturing effort.
3Power
If the flow guiding device height is increased to improve lift generation, then the aerodynamic performance is improved, but the drag increases significantly
Solution Approach 1:
The device parameters (height, spacing, angle) are systematically optimized to achieve the desired lift-drag balance. By carefully selecting these parameters, the device generates sufficient lift while limiting drag increase to acceptable levels.
Solution Approach 2:
Rather than using a single tall flow guiding element that would generate excessive drag, the invention uses multiple smaller elements distributed along the transition region. This partial action approach achieves cumulative lift improvement while each individual element creates minimal drag.
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
The flow guiding device enhances the lift-to-drag ratio by up to 10% compared to conventional designs, leading to a 1-1.5% annual energy yield increase, providing substantial economic benefits over the blade's lifetime.
Implementation Method 1
the flow guiding device is arranged so as to generate a separation of airflow along at least a central longitudinal portion of the flow guiding device from the pressure side of the blade
Implementation Method 2
the profiled contour when being impacted by an incident airflow generating a lift
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention discloses a wind turbine blade (10) with a flow guiding device (70) attached to a profiled contour (40, 42, 50) on a pressure side (52) of the blade. The flow guiding device extends along at least a longitudinal part of a transition region (32) of the blade and is arranged so as to generate a separation of airflow along at least a central longitudinal portion (71) of the flow guiding device from the pressure side of the blade at a point between the flow guiding device and a trailing edge (20) of the blade, when the blade is impacted by an incident airflow. The flow guiding device is arranged at a relative chordal position, seen from the leading edge of the blade, lying in an interval between 40% and 92%. The height of the flow guiding device to the profiled contour is at least 10% of a maximum thickness of the profiled contour for each transverse cross section.