Closed-Loop Multi-Blade Wind Turbine for Higher Power Density
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Solution Overview
Problem
Existing wind turbines, particularly multiple blade designs, suffer from suboptimal power output and efficiency, necessitating improvements to enhance energy generation capabilities.
Innovation Solution
A multiple blade wind turbine design featuring closed loop tracks with airfoil-shaped blades oriented perpendicular to airflow, spaced to form linear cascades, and equipped with a transmission system to optimize airflow dynamics and generate power through a high aspect ratio and adjustable pitch angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple blade wind turbines use conventional airfoil arrangements, then power output can be generated, but efficiency and power density remain suboptimal
Solution Approach 1:
The rotor is segmented into multiple independent airfoil-shaped blades (typically 7-15 blades) arranged in a circular pattern around the horizontal axis. Each blade operates independently to extract energy from the wind, allowing the system to process more kinetic energy simultaneously compared to conventional 3-blade designs, thereby improving power output while maintaining efficiency
Solution Approach 2:
The patent transitions from conventional vertical airfoils to horizontal airfoils that extend radially outward from the central axis. This dimensional change allows the blades to be positioned perpendicular to the wind direction, maximizing the swept area and enabling more effective extraction of kinetic energy from the wind stream, thus improving both power output and efficiency
2Power
If wind turbines use high-speed airfoil-type rotor blades, then electricity generation is achieved, but blade tip losses reduce overall efficiency
Solution Approach 1:
The airfoil-shaped blades are designed with dynamic characteristics that allow them to flex and adjust to varying wind conditions. The blades operate at lower rotational speeds compared to conventional high-speed designs, reducing centrifugal forces and blade tip vortices that cause energy losses, while still maintaining effective power generation through the increased number of blades
Solution Approach 2:
The patent changes key operational parameters including blade speed ratio (maintaining tip speed below 0.3 times the wind speed), blade spacing (1.0-2.5 chord lengths), and pitch angles (-90 to 90 degrees). These parameter changes optimize the aerodynamic performance by minimizing blade tip losses and maximizing lift-to-drag ratios, thereby improving overall efficiency while maintaining power generation
3Power
If closed loop tracks with horizontal airfoils are used, then power generation is achieved, but manufacturing and maintenance costs increase
Solution Approach 1:
All airfoil-shaped blades are designed with identical geometry, spacing, and attachment mechanisms to the closed loop tracks. This homogeneity allows for standardized manufacturing processes, mass production of identical blade components, and simplified maintenance procedures where any blade can be replaced with any other, significantly reducing manufacturing and maintenance costs despite the complex closed loop track structure
4Force
If airfoil-shaped blades are spaced closely to form linear cascades, then lift force increases, but blade spacing requirements complicate design
Solution Approach 1:
The patent employs asymmetric blade spacing where the first set of airfoil-shaped blades is positioned at specific angular intervals (1.0-2.5 chord lengths apart) to maximize lift generation, while the second set is positioned at different intervals to optimize wake interaction. This asymmetric arrangement creates linear cascades that enhance lift force while managing the complexity through systematic positioning rather than random placement
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 design achieves higher power density, increased lift force, and reduced blade tip losses, exceeding the Betz limit with a maximum power coefficient above unity, allowing efficient power generation even in low wind speeds and reducing manufacturing and maintenance costs.
Implementation Method 1
a plurality of airfoil-shaped blades interspaced within the set of closed loop tracks. Each airfoil-shaped blade is oriented perpendicular to the airflow
Implementation Method 2
Each airfoil-shaped blade is spaced between 1.0 and 2.5 chord lengths apart
Implementation Method 3
a transmission, and an electric generator connected to the transmission. The transmission is mechanically coupled to the set of closed loop tracks such that the set of closed loop tracks drives the transmission
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A multiple blade wind turbine includes a base, a central support tower, and at least one rotor. The central support tower extends vertically from the base and is adapted to support the rotor. The rotor includes airfoil-shaped blades and an electric generator coupled to a set of closed loop tracks via a transmission. The set of closed loop tracks is spaced vertically apart from each other. The airfoil-shaped blades are interspaced within the set of closed loop tracks. Each airfoil-shaped blade is oriented perpendicular to the airflow and connected at each end to one of the set of closed loop tracks such that a windward and a leeward set of airfoil-shaped blades are aligned to form a linear cascade of parallel airfoil-shaped blades. Each airfoil-shaped blade has a pitch angle between -90 and 90 degrees and each airfoil-shaped blade is spaced between 1.0 and 2.5 chord lengths apart.