Vertical Axis Turbine Contra-Rotating Rotor Vibration Cancellation
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Solution Overview
Problem
Existing small wind turbines for domestic and urban use, particularly those with horizontal axis configurations, face inefficiencies due to constant directional changes in wind, resulting in significant vibrations, noise, and reduced electricity production, while large vertical axis turbines are not scalable for roof or chimney mounting.
Innovation Solution
A vertical axis turbine design featuring contra-rotating rotors with a central generator, where each rotor is a mirror image of the other, equipped with cantilevered aerofoil blades and an axial flux generator, minimizing vibrations and noise, and allowing for a compact, lightweight, and efficient power generation system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a horizontal axis wind turbine is used, then it can capture wind energy, but it spends a lot of time hunting the winds that change direction constantly in urban areas, producing significant horizontal and gyroscopic forces and vibrations
Solution Approach 1:
The patent inverts the conventional horizontal axis configuration by using a vertical axis configuration. This inversion allows the turbine to capture wind from any direction without hunting, as the vertical arrangement naturally accommodates multi-directional wind flow. The contra-rotating blades further enhance this by maintaining stable operation regardless of wind direction, eliminating the harmful vibrations and noise associated with horizontal axis turbines in urban environments.
Solution Approach 2:
The patent employs asymmetric blade arrangements where the blades are positioned at different orientations (e.g., 0度和180度) to create contra-rotating motion. This asymmetric configuration allows the turbine to capture wind energy efficiently from any direction while the opposing rotation of blades cancels out vibrations and gyroscopic forces, resolving the contradiction between productivity and harmful vibrations.
2Power
If a horizontal axis wind turbine is used, then it can generate power, but it produces significant horizontal and gyroscopic forces on its mountings
Solution Approach 1:
The patent uses contra-rotating blades that rotate in opposite directions to create counterbalancing forces. The gyroscopic and horizontal forces generated by one blade are counteracted by the opposite rotation of the other blade, effectively canceling out the net forces on the mounting structure. This allows the turbine to generate power without imposing significant horizontal or gyroscopic forces on its foundation.
Solution Approach 2:
By inverting to a vertical axis configuration, the patent eliminates the conventional horizontal force vectors that cause gyroscopic effects. The vertical arrangement means that wind forces act primarily in the vertical plane, and the contra-rotating blades ensure that remaining horizontal components cancel out, thereby eliminating the harmful forces that would otherwise be transmitted to the mounting structure.
3Productivity
If large scale vertical axis wind turbines are used, then they can capture wind energy, but they are not readily scalable for roof or chimney mounting
Solution Approach 1:
The patent segments the turbine into compact, modular components that can be scaled down for roof or chimney mounting. The vertical axis configuration with contra-rotating blades allows for a compact form factor that can be integrated into urban environments. The generator and rotor assembly can be scaled to match different installation spaces while maintaining the essential contra-rotating mechanism that provides vibration cancellation and efficient wind energy capture.
Solution Approach 2:
The patent transitions from large-scale horizontal axis turbines to a vertical axis configuration, utilizing the vertical dimension to achieve compactness. This dimensional change allows the turbine to fit on roofs and chimneys by stacking components vertically rather than spreading them out horizontally. The contra-rotating blades are arranged in a compact vertical plane, enabling scalable deployment in urban domestic locations without requiring large footprints.
4Object-affected harmful factors
If contra-rotating blades are used, then vibrations and gyroscopic forces are cancelled out, but the design becomes more complex
Solution Approach 1:
The patent merges the contra-rotating blade assembly with the rotor and generator into an integrated unit. The generator is positioned between the contra-rotating blades, and the entire assembly rotates together as a single unit. This merging simplifies the overall structure by eliminating the need for separate drive trains and complex mounting mechanisms, while still achieving vibration cancellation through the contra-rotating configuration.
Solution Approach 2:
The rotor assembly serves multiple functions simultaneously: it supports the contra-rotating blades, houses the generator, and provides the rotating structure for electricity generation. The generator itself serves both as the power generation device and as a counterweight to balance the rotating blades. This multi-functionality reduces the number of separate components needed, thereby reducing overall design complexity while maintaining the benefits of vibration cancellation.
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 contra-rotating design doubles the effective wind speed for generators, cancels out vibrations, reduces noise and mechanical loads, and enables efficient power production in low wind conditions, making it suitable for urban and tidal flow applications with reduced weight and structural requirements.
Implementation Method 1
A wind turbine, generally indicated at 10 has a vertically extending shaft 11 which carries rotors 12,13 for contra-rotation thereon
Implementation Method 2
The generator conveniently comprises a first plate 18 mounted on rotor 12 and a second plate 19 mounted on rotor 11. In this example, plate 18 carries magnets 20, whilst plate 19 carries coils 21. Electricity generated by the magnetic flux lines by the coils, due to the relative rotation
Implementation Method 3
Each rotor 12, 13, comprises a central hub 15, a number of spaced cantilevered arms 16 (typically 3) and an upstanding aerofoil section blade 17 attached to each arm
Data Source
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AI summary
This invention relates to vertical axis turbines particularly ones which are suitable for use in swirling conditions. The vertical turbine (10) may have first and second rotors (13,14) mounted about the axis for contra rotation and a generator (14) located between the rotors for generating electricity in response to rotation of the rotors characterised in that one rotor is a substantial mirror image of the other.