Sigmoidal Vertical Axis Wind Turbine Rotor Blades

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Solution Overview

Problem

Vertical axis wind turbines (VAWTs) have lower efficiency compared to horizontal axis wind turbines and face issues such as high construction costs, non-self-starting designs, and susceptibility to fatigue and buckling, while existing designs that improve efficiency often compromise on robustness and visibility.

Innovation Solution

A rotor design featuring blades with 180° offset, radially curved sections, and a sigmoidal shape with overlapping passageways, optimized for lift and drag forces, which enhances power conversion efficiency and robustness while minimizing visual flicker and buckling risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If aerofoil blade shapes are used to improve power conversion efficiency, then efficiency is improved, but construction cost increases and self-starting capability is lost

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidconstruction cost

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The blade employs a curved cross-sectional shape with a rounded leading edge and a tapered trailing edge, rather than a flat or simple aerofoil shape. This curvature optimization improves wind capture efficiency while maintaining manufacturing simplicity using standard sheet materials, resolving the contradiction between efficiency and construction cost.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Productivity

If aerofoil blade shapes are used to improve power conversion efficiency, then efficiency is improved, but self-starting capability is lost

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidself-starting capability

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The blade features an asymmetric cross-sectional shape with a rounded leading edge and a sharper trailing edge, creating differential drag and lift characteristics that enable self-starting. The asymmetric geometry allows the blade to capture wind effectively at various rotation angles, generating enough initial torque to start rotation without external assistance while maintaining high efficiency during operation.

Inventive Principle:

Principle #4Asymmetry

3Ease of manufacture

If flat parallel-sided central section is used, then construction is simplified, but visual flicker becomes noticeable and buckling resistance decreases

Engineering Contradiction:

Improveconstruction simplicityVSAvoidvisual flicker

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The blade replaces the flat parallel-sided central section with a curved cross-sectional shape that follows a smooth arc. This curvature eliminates the flat surfaces that cause visual flicker when rotating, creating a more aesthetically pleasing appearance while maintaining construction simplicity through the use of standard curved sheet materials.

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Ease of manufacture

If flat parallel-sided central section is used, then construction is simplified, but buckling resistance in strong winds decreases

Engineering Contradiction:

Improveconstruction simplicityVSAvoidbuckling resistance

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The curved cross-sectional shape with optimized radius of curvature provides superior structural rigidity compared to flat sections. The curved geometry distributes wind loads more effectively across the blade surface, increasing resistance to buckling and deformation in strong winds while maintaining ease of construction using standard curved materials.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 a significant improvement in power output and rotation rate, with enhanced torque and self-starting capabilities, offering higher efficiency and robustness compared to prior art, while reducing visual flicker and buckling issues.

Implementation Method 1

relying on the lift forces generated by the wind passing over rapidly rotating blades, to extract power from the wind

Methodology Applied

Scientific EffectLift force: Aerofoil

Implementation Method 2

Power is extracted from the wind via a combination of lift and drag forces on the blades

Methodology Applied

Scientific EffectDrag force: Drag

Data Source

PatentUS11220995B2Rotor for a vertical axis wind turbine

Publication Date: 2022.01.11 SPINETIC ENERGY

AI summary

There is described a rotor for a vertical axis wind turbine comprising: first and second blades connected to one another and arranged to rotate around an axis; wherein the first and second blades are disposed 180° apart with respect to one another and are offset from the axis in a radial direction; wherein an inner edge of each blade is spaced radially inwardly from an outer edge of the opposing blade to form a pair of diametrically opposed openings which open in opposite directions; wherein each of the first and second blades comprises a first curved section and a second oppositely curved section, the first and second curved sections being separated by a point of inflection; and wherein the first and second curved sections of the first and second blades overlap one another to form a passageway between the first and second blades which extends between the openings.