Rotary Blade Active Flow Control via Centrifugal Air Compression

Solution Overview

Problem

Rotary devices such as helicopters and wind turbines experience performance reductions due to cross flow, including loss of lift and increased vibration, which existing active aerodynamic flow control methods cannot fully mitigate without the need for expensive and space-prohibitive compressed air supplies.

Innovation Solution

The implementation of a rotor blade system with an air channel sealed at the tip and an inlet at the root, utilizing centrifugal force to generate a pressure gradient for active flow control, eliminating the need for external compressed air by using the rotating blade dynamics to create a compressed air source within the blade.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If compressed air supply is used for active flow control, then performance reduction due to cross flow is mitigated, but cost and space requirements increase

Engineering Contradiction:

Improveperformance mitigationVSAvoidcompressed air supply requirement

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The rotor blade system generates its own compressed air supply through the rotating blade dynamics and centrifugal effect, eliminating the need for external compressed air supply systems. The air channel within the blade utilizes the rotation to create pressure gradient, with air entering at the root and being compressed by centrifugal force, then discharged at outlets along the blade for active flow control.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system uses the dynamic rotation of the blade to create the compressed air supply. The centrifugal effect generated during rotation creates a pressure gradient along the air channel, transforming the static blade structure into a dynamic air compression system that operates only when the blade is rotating.

Inventive Principle:

Principle #15Dynamics

2Force

If air injection is used for active flow control, then lift loss is reduced, but the requirement for compressed air supply increases cost and space

Engineering Contradiction:

ImproveliftVSAvoidcompressed air supply

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The rotor blade system generates its own compressed air supply through the rotating blade dynamics and centrifugal effect, eliminating the need for external compressed air supply systems. The air channel within the blade utilizes the rotation to create pressure gradient, with air entering at the root and being compressed by centrifugal force, then discharged at outlets along the blade for active flow control.

Inventive Principle:

Principle #25Self-service

3Stability of the object's composition

If traditional active aerodynamic flow control is implemented, then vibration is reduced, but expensive and space-prohibitive compressed air supply is required

Engineering Contradiction:

ImprovevibrationVSAvoidcompressed air supply infrastructure

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The rotor blade system generates its own compressed air supply through the rotating blade dynamics and centrifugal effect, eliminating the need for external compressed air supply systems. The air channel within the blade utilizes the rotation to create pressure gradient, with air entering at the root and being compressed by centrifugal force, then discharged at outlets along the blade for active flow control.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system uses the dynamic rotation of the blade to create the compressed air supply. The centrifugal effect generated during rotation creates a pressure gradient along the air channel, transforming the static blade structure into a dynamic air compression system that operates only when the blade is rotating.

Inventive Principle:

Principle #15Dynamics

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 enhances performance by reducing vibrations and preventing dynamic stall without requiring an external compressed air supply, thereby improving lift and thrust efficiency in rotary devices.

Implementation Method 1

The centrifugal effect of rotating rotor blades generates a pressure gradient along the blade which can be used as a compressed air source for active flow control.

Methodology Applied

Scientific EffectCentrifugal effect: Centrifugal Force

Data Source

PatentUS10302064B2Methods and systems for rotary wing active flow control

Publication Date: 2019.05.28 THE BOEING CO

AI summary

Within examples, systems for enhanced performance blades for rotor craft are provided and methods for operation. An example system for a rotary device is provided comprising a rotor blade coupled to a rotor hub. The system also comprises an air channel disposed within the rotor blade, where the air channel is sealed proximate to a distal end of the rotor blade. The system also comprises an inlet positioned at a proximal end of the rotor blade, where the inlet is in fluid communication with the air channel. The system also comprises a plurality of outlets positioned along the rotor blade, where each of the plurality of outlets are in fluid communication with the air channel.