Multi-rotor Wind Turbine with Nested Secondary Rotors
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Solution Overview
Problem
Current wind turbine designs, particularly those with vertical and horizontal axis rotors, fail to fully capture wind energy due to inefficiencies in energy utilization, as they operate with low efficiency and do not effectively harness the wind velocity and rotational velocity, leading to a fraction of energy being captured at a single turbine location.
Innovation Solution
A multi-rotor, multi-axis wind turbine system where primary rotors drive secondary rotors into the airflow, with adjustable vanes and orientations that maximize lift and minimize drag, allowing for control over the relative net vector velocity of secondary rotors, thereby capturing both wind and rotational velocities to increase energy capture efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If single rotors are used in conventional wind turbines, then the device complexity is reduced, but the energy capture efficiency deteriorates because only a fraction of wind velocity is captured at a single turbine location
Solution Approach 1:
The wind turbine is divided into multiple rotors (primary rotor and secondary rotors) that operate independently but interact aerodynamically. Each rotor captures a portion of the wind energy, and their combined effect significantly increases total energy capture efficiency compared to a single rotor system.
Solution Approach 2:
Secondary rotors are positioned within the swept area of the primary rotor, creating a nested configuration where smaller rotors operate in the wake and induced flow fields of the larger primary rotor. This nested arrangement allows multiple rotors to occupy the same spatial envelope, multiplying energy capture without proportionally increasing device complexity.
2Productivity
If fixed angle of attack vanes are used, then the manufacturing precision is improved, but the energy capture efficiency deteriorates because drag is not minimized and lift is not maximized across varying wind conditions
Solution Approach 1:
The vanes are designed with adjustable angle of attack mechanisms that allow dynamic optimization of aerodynamic performance. By adjusting the vane angles, the system can minimize drag and maximize lift across varying wind conditions, significantly improving energy capture efficiency compared to fixed angle designs.
Solution Approach 2:
The angle of attack parameter of the vanes is made variable rather than fixed. This allows the system to adapt to changing wind velocities and directions, optimizing the aerodynamic coefficients (drag and lift) in real-time to maximize power extraction from the wind.
3Productivity
If secondary rotors are positioned close to the primary axis, then the device complexity is reduced, but the energy capture efficiency deteriorates because the relative net vector velocity of secondary rotors is reduced
Solution Approach 1:
Secondary rotors are positioned at an optimized radial distance from the primary axis, utilizing the three-dimensional space within the primary rotor's swept area. This spatial arrangement maximizes the relative net vector velocity of secondary rotors by positioning them in regions of optimal wind flow and induced velocity, thereby maximizing their contribution to total power generation.
4Productivity
If large arrays of single turbines are deployed, then the total energy capture is improved, but the device complexity and land use increase, and each individual turbine operates with low efficiency
Solution Approach 1:
Multiple rotors are merged into a single turbine platform, with primary and secondary rotors working together in a coordinated manner. This consolidation achieves the total energy capture that would otherwise require multiple separate turbines, while reducing land use, infrastructure complexity, and improving the efficiency of each individual turbine location.
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 design significantly enhances energy capture by increasing the relative net vector velocity of secondary rotors, resulting in higher power output, as the power output is a function of the cubed velocity of the relative air speed, and allows for greater control over energy generation by adjusting the primary rotor's angle of attack.
Implementation Method 1
a primary rotor connected to support arms that extend radially from a primary axis... as the primary rotor is rotated by wind velocity
Implementation Method 2
the coefficient of lift for a given secondary rotor... the rotational velocity of the primary rotor and the distance from the primary axis, which further maximizes the coefficient of lift over drag
Implementation Method 3
the coefficient of drag imposed on the secondary rotors is less than the coefficient of lift for a given secondary rotor
Data Source
AI summary
A multi-rotor, multi-axis wind turbine where the rotors are in relative motion to one another to maximize the energy captured and thus generated, where there is a primary rotor axis and direction and one or more secondary rotor axes, where each rotor rotates about a different axis, and the rotors can operate in either a horizontal or vertical axis orientation or some orientation in between, and there are at least two rotor axes operating in different directions such that the relative motion of the primary rotor drives at least one secondary rotor into the surrounding air increasing the relative net vector velocity of the secondary rotor with respect to the wind velocity and surrounding air which increases the amount of energy captured at a given location for a given wind velocity over the prior art.