Rotor Blade Vortex Generators for UAV Propeller Noise and Efficiency

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Solution Overview

Problem

Existing multi-rotor aircraft propellers face efficiency and noise challenges, with conventional designs often compromising between efficiency and noise reduction, and existing modifications may not be universally applicable, leading to reduced performance in consumer-grade UAVs.

Innovation Solution

The integration of miniature vortex generators along the upper surface of rotor blades, formed through injection molding, which enhance energy exchange between low-energy and high-energy fluid layers, delaying boundary layer separation and reducing noise by introducing protrusions or depressions strategically positioned to prevent flow separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a smooth surface is used on propellers, then manufacturing is simple, but propeller efficiency is reduced due to early boundary layer separation

Engineering Contradiction:

Improvepropeller manufacturing simplicityVSAvoidpropeller efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies vortex generators only at specific locations on the propeller blade surface where boundary layer separation is most likely to occur, rather than modifying the entire surface. This localized approach maintains manufacturing simplicity while improving efficiency at critical areas.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent modifies the surface parameters by adding small vortex generator elements with specific dimensions, shapes, and spacing parameters. These parameter changes trigger beneficial flow characteristics that delay boundary layer separation without requiring complete surface redesign.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the front or rear part of propeller surface is roughened, then performance may be improved, but it is not universally applicable and may reduce efficiency in some cases

Engineering Contradiction:

Improvepropeller performanceVSAvoidapplicability across different propeller types

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The vortex generator design provides a localized flow control solution that can be applied to specific regions of various propeller types without requiring complete surface roughening, making it more universally applicable than blanket roughening approaches.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The vortex generators act as intermediary elements that mediate between the smooth propeller surface and the airflow, providing controlled turbulence where needed while maintaining the overall smooth surface architecture applicable to different propeller designs.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional propeller designs are used, then manufacturing is simple, but noise levels are high due to propeller rotation and flow separation

Engineering Contradiction:

Improvepropeller manufacturing simplicityVSAvoidpropeller noise

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

By placing vortex generators only at specific locations where flow separation initiates, the patent reduces noise-generating flow separation events without requiring complete surface modification, maintaining manufacturing simplicity while lowering noise.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent converts the potentially harmful effect of surface modifications into a beneficial flow control mechanism. The vortex generators create controlled turbulence that prevents larger, more noise-generating flow separation events downstream.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 solution improves propeller efficiency by up to 5.3% and reduces noise levels by 7±2 dB, effectively addressing the limitations of conventional propeller designs by delaying boundary layer separation and minimizing noise emission.

Implementation Method 1

The vortex generators are designed as an effective flow control device that operates to generate a flow vortex to enhance the energy exchange between the low-energy fluid and the mainstream high-energy fluid in the boundary layer, and delay boundary layer separation across the blade airfoil.

Methodology Applied

Scientific EffectVortex generator: Vortex Generator

Implementation Method 2

enhance the energy exchange between the low-energy fluid and the mainstream high-energy fluid in the boundary layer, and delay boundary layer separation across the blade airfoil

Methodology Applied

Scientific EffectBoundary layer: Boundary Layer

Data Source

PatentUS11827340B2Aerial vehicle with rotor blade assembly having rotor blade including vortex generator

Publication Date: 2023.11.28 HANGZHOU ZERO ZERO TECH CO LTD

AI summary

An unmanned aerial vehicle includes a fuselage body and a lift mechanism. The lift mechanism includes a rotor blade assembly and a rotary driving member and defines an axis of rotation. The lift being mechanism is coupled to the fuselage body. The rotary driving member is configured to controllably rotate the rotor blade assembly about the axis of rotation. The rotor blade assembly includes at least one rotor blade. The at least one rotor blade including a vortex generator defined along an upper surface of the rotor blade.