Propeller Blade Tip Slot and Partition for Vortex Reduction

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Solution Overview

Problem

Existing propeller blades and wind turbine blades with wide tips suffer from significant energy losses due to vortex generation at the blade tips, which are not effectively addressed by previous solutions that focus on material reliefs, holes, or complex control elements, neglecting strength and pressure irregularity issues.

Innovation Solution

A propeller blade design featuring a slot connecting the pressure and suction sides, divided into sections by a partition wall, with specific distance proportions and a pressure equalizing channel, which reduces vortex interference by creating counter-rotation and equalizing pressure differences, enhancing strength and reducing air resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the width of propeller blades is increased to achieve desired performance with limited diameter, then the power transmission capability is improved, but significant vortices are generated at the blade tips causing energy loss and efficiency degradation

Engineering Contradiction:
Improvepower transmission capabilityVSAvoidenergy loss from blade tip vortices
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The blade tip is segmented by dividing it into multiple sections using partition walls, creating multiple slot-sections instead of a single continuous slot. This segmentation allows for better control of flow patterns and vortex generation at the blade tip, reducing energy loss while maintaining the required blade width for power transmission

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Pressure equalizing elements (channels or cavities) are introduced as intermediary structures between the slot-sections to equalize pressure differences. These intermediaries prevent sudden pressure equalization that would cause strong vortices, thereby reducing energy loss at the blade tips while preserving the blade's power transmission capability

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If the number of blades is increased to achieve desired performance, then the power transmission capability is improved, but the blades interfere with each other from a flow point of view

Engineering Contradiction:
Improvepower transmission capabilityVSAvoidblade interference
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The invention applies local quality modifications at the blade tips through slots and partition walls, creating localized flow control features that reduce vortex generation. This allows each blade to operate more independently, reducing interference effects when multiple blades are used to achieve desired power transmission

Inventive Principle:
Principle #3Local quality

3Loss of energy

If complex control devices or geometries are used to reduce blade tip vortices, then energy loss is reduced, but the device complexity increases

Engineering Contradiction:
Improveenergy loss from blade tip vorticesVSAvoidstructural complexity of vortex reduction device
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The vortex reduction functionality is merged with the blade structure itself by integrating slots and partition walls directly into the blade design. This combining of functions reduces the need for separate complex control devices while achieving effective vortex reduction and energy loss mitigation

Inventive Principle:
Principle #5Merging (Combining)

4Loss of energy

If material reliefs or holes are used to reduce vortices at blade tips, then energy loss is reduced, but the structural strength is compromised

Engineering Contradiction:
Improveenergy loss from blade tip vorticesVSAvoidstructural strength of blade
Core Design Contradiction:
Loss of energyVSStrength

Solution Approach 1:

The continuous slot is segmented into multiple slot-sections by partition walls, which distributes the structural compromise across multiple smaller sections rather than one large opening. This segmentation maintains better structural integrity while still achieving vortex reduction and energy loss mitigation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Pressure equalizing elements serve as intermediaries that connect slot-sections while maintaining structural continuity. These elements allow pressure equalization for vortex reduction while preserving the overall structural strength of the blade better than simple holes or reliefs would

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively minimizes energy losses by creating counter-vortices that extinguish harmful vortices at the blade tips, while maintaining structural integrity and reducing air resistance, thus improving efficiency and service life.

Implementation Method 1

the slot contains a pressure equalizing element, which pressure equalizing element is a channel connecting the neighboring slot-sections

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Implementation Method 2

The invention reduces or eliminates flow losses at the blade tip by providing uniform flow conditions along the entire width of the blade tip

Methodology Applied
Scientific EffectVortex interference: Vortex Ring

Data Source

PatentEP3984882B1Propeller and propeller blade
Publication Date: 2024.03.20 CIRUS ROBERT
  • EP3984882B1 patent drawingFigure 1~2
  • EP3984882B1 patent drawingFigure 3~5
  • EP3984882B1 patent drawingFigure 6~7

AI summary

The invention relates to a propeller blade having a minimal blade tip loss, which propeller blade has a pressure side and a suction side opposite thereto, a blade root adapted to be connected to a propeller, a blade tip (6) at the end of the propeller blade opposite the blade root, wherein a slot (9) is formed within the propeller blade connecting the pressure side with the suction side, the slot (9) has an inlet opening formed on the pressure side and an outlet opening formed on the suction side, wherein the propeller blade contains a pressure equalizing element (13). The invention further relates to a propeller for aircrafts, helicopters, wind turbines with horizontal axis, fans and drones, which propeller is provided with at least one propeller blade according to the first aspect of the invention.