Cross-Flow Wind Turbine Rotor With Secondary Blades to Reduce Return Drag
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Solution Overview
Problem
Conventional drag-based wind turbines suffer from inefficiencies due to wind impingement on returning blades, self-starting problems, and increased return drag when additional blades are added, leading to reduced performance and mechanical inefficiencies.
Innovation Solution
A cross-flow wind turbine design incorporating primary and secondary blades that interact to enhance performance by concentrating and redirecting wind energy, reducing return drag, and stabilizing torque transmission through alternating blade configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If additional blades are added to increase wind capture, then wind energy capture is improved, but return drag increases and performance decreases
Solution Approach 1:
The rotor is segmented into primary blades and secondary blades that are spatially separated and functionally distinct. Primary blades capture wind energy while secondary blades redirect airflow, preventing the return drag problem that occurs when additional blades are added to conventional single-type rotors. This segmentation allows increasing blade quantity without proportionally increasing return drag.
Solution Approach 2:
Secondary blades act as intermediaries between the primary blades and the returning airflow. They redirect the wind that would otherwise impinge on returning primary blades, converting potentially harmful return drag into useful airflow that continues to drive the rotor. This intermediary function resolves the contradiction between capturing more wind energy and avoiding return drag losses.
2Device complexity
If conventional drag-based design is used, then simplicity is maintained, but wind impingement on returning blades causes inefficiency
Solution Approach 1:
The rotor is divided into functionally distinct primary and secondary blade sets. Primary blades are optimized for capturing wind energy while secondary blades are optimized for redirecting airflow. This segmentation resolves the inefficiency of wind impingement on returning blades while maintaining relative design simplicity through the use of two straightforward blade types rather than complex adjustable mechanisms.
Solution Approach 2:
The design converts the harmful effect of returning blades being impinged upon by wind into a beneficial process. Secondary blades intentionally redirect this airflow to continue driving the rotor, transforming what was previously a source of drag and inefficiency into an additional source of driving force. This resolves the contradiction by maintaining simple drag-based geometry while eliminating the productivity loss.
3Device complexity
If primary blades alone are used, then design is simple, but torque transmission is unstable
Solution Approach 1:
The blade system is segmented into primary and secondary blades that work in alternating sequence. As primary blades extract energy from the wind, secondary blades redirect the airflow to continue rotating the rotor. This alternating action between two blade types stabilizes torque transmission by ensuring continuous driving force throughout the rotation cycle, preventing the instability that would occur with uniform single-type blades.
Solution Approach 2:
The interaction between primary and secondary blades creates a continuous cycle of wind capture and redirection. Rather than having intermittent torque pulses, the alternating blade configuration ensures that as one set of blades passes through less effective positions, the other set continues to generate driving force. This continuity stabilizes torque transmission while maintaining relatively simple blade geometry.
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 increases wind capture and torque transmission efficiency, reduces return drag, and stabilizes torque application, improving overall performance and reducing mechanical fatigue.
Implementation Method 1
conventional drag-based wind turbines suffer from inefficiencies cause when wind impinges returning blades
Implementation Method 2
wind turbines can be readily deployed at specific locations where power generated from the wind turbines may be used directly at the site of deployment
Data Source
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AI summary
A wind turbine rotor includes an axle, a plurality of primary blades disposed at regular intervals around the axle, and a plurality of secondary blades disposed around the axle between primary blades of the plurality of primary blades. Each secondary blade of the plurality of secondary blades is smaller than each primary blade of the plurality of primary blades.