Compound Savonius Blade Structure for Stable Torque Output

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Solution Overview

Problem

Savonius wind turbines experience inefficiency due to cyclic torque variation, which is not as efficient as other types of wind turbines.

Innovation Solution

The design incorporates a compound blade with a primary and secondary blade portion, where the secondary blade portion is oriented perpendicular to the primary blade portion and scaled to have a larger torque radius, ensuring consistent torque generation throughout the rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a traditional savonius wind turbine with single blade portions is used, then the structure is simple, but the torque generation is inconsistent and efficiency is low

Engineering Contradiction:
ImproveefficiencyVSAvoidblade structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The blade is divided into multiple blade portions (primary and secondary) with different orientations and torque radii. Each blade portion contributes to torque generation at different rotational positions, segmenting the torque production function across multiple structural elements to achieve more consistent overall torque output.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a second dimensional aspect to the blade structure by adding blade portions oriented at different angles (e.g., perpendicular orientations) around the rotational axis. This multi-dimensional arrangement ensures that at least one blade portion is effectively positioned to capture wind force throughout the rotation cycle, maintaining more consistent torque generation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If the secondary blade portion is added with larger torque radius, then the torque consistency is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvetorque consistencyVSAvoidblade assembly
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The blade is segmented into primary and secondary blade portions that can be manufactured separately and then assembled together. This segmentation allows each portion to be optimized independently for its specific function while simplifying the manufacturing process compared to creating a single complex blade structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple blade portions with different orientations and torque radii are merged into a single compound blade assembly. The primary and secondary blade portions are combined such that they work together to produce consistent torque, merging simple geometric shapes (e.g., semicircular sections) into a functional whole that achieves torque stability.

Inventive Principle:
Principle #5Merging (Combining)

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 more consistent torque generation and increased efficiency by leveraging the secondary blade portion to balance torque fluctuations, enhancing overall performance.

Implementation Method 1

As wind contacts the blades, it will impart a greater drag force on a concave side than it will on a convex side, causing rotation of the blades about the vertical axis

Methodology Applied
Scientific EffectWind force: Wind Power

Implementation Method 2

As wind contacts the blades, it will impart a greater drag force on a concave side than it will on a convex side, causing rotation of the blades about the vertical axis

Methodology Applied
Scientific EffectDrag force: Drag

Data Source

PatentEP4278084B1Modified savonius wind turbine
Publication Date: 2025.12.24 UNIVERSITY OF CINCINNATI
  • EP4278084B1 patent drawingFigure 1
  • EP4278084B1 patent drawingFigure 2
  • EP4278084B1 patent drawingFigure 3

AI summary

A savonius wind turbine including a rotational shaft and a compound blade operatively coupled to the rotational shaft is provided. The compound blade includes a primary blade portion and a secondary blade portion. The primary blade portion extends between a first end and a second end and defines a primary concave surface therebetween. The secondary blade portion is coupled to the primary blade portion between the first end and the second end. The secondary blade portion defines a secondary concave surface configured to generate a torque about the rotational shaft.