Optical Airflow Sensor Using Light Modulation

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Solution Overview

Problem

Current methods for measuring aerodynamic flow on aircraft surfaces, such as using flow cones and tracer injection, are limited by inability to provide precise, real-time data across all zones, especially on masked areas like the underside of aircraft, and lack objective criteria for flow characterization.

Innovation Solution

A device comprising an optical sensor with a movable part that modulates illumination distribution to measure airflow orientation, using ambient light and printed organic electronic components for precise angular measurements, allowing real-time data acquisition and processing across all aircraft surfaces without visual obstruction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If flow cones are used to measure aerodynamic flow, then real-time visualization is enabled, but precise measurement of flow direction and access to obscured areas are not achieved

Engineering Contradiction:
Improveflow direction measurement precisionVSAvoidaccess to obscured areas
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical flow cone system with an optical sensing system. A movable opaque part modulates light reaching photodetectors based on airflow direction, enabling precise measurement without requiring physical visibility or line-of-sight to the measurement point. This substitution allows measurement in obscured areas while maintaining directional precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary optical system between the airflow and the measurement device. Instead of directly observing flow cones, the system uses ambient light modulated by a movable opaque part to indicate flow direction. This intermediary mechanism enables indirect measurement in areas where direct observation is impossible.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Area of stationary object

If tracer injection is used for flow characterization, then comprehensive flow coverage is achieved, but real-time measurement and multiple test points per flight are not possible

Engineering Contradiction:
Improveflow coverage areaVSAvoidmeasurement time per test point
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

The patent segments the flow measurement function into multiple distributed optical sensors across the aircraft surface. Each sensor independently measures local flow direction, enabling simultaneous multi-point measurement. This segmentation allows comprehensive coverage while maintaining real-time data acquisition from numerous locations concurrently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables continuous real-time measurement through the optical sensor system. Unlike tracer injection which requires stabilization time and sequential measurement, the optical sensors provide continuous directional data from multiple points simultaneously, eliminating time loss between test points and enabling ongoing flow characterization throughout the flight.

Inventive Principle:
Principle #20Continuity of useful action

3Weight of moving object

If flow cones are used, then lightweight and free movement are achieved, but instability unrelated to flow characteristics occurs

Engineering Contradiction:
Improveflow indicator weightVSAvoidflow measurement reliability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent replaces the mechanical flow cone indicator with an optical detection system. Instead of relying on the physical stability and alignment of lightweight cones, the system uses photodetectors to measure light modulation caused by airflow-driven movement of an opaque part. This substitution eliminates mechanical instability while maintaining sensitivity to flow characteristics.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Device complexity

If ambient light is used for optical measurement, then no additional light source is required, but measurement precision in varying light conditions must be maintained

Engineering Contradiction:
Improvelight source requirementVSAvoidangular measurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent employs ambient light as the measurement source, allowing the system to self-utilize available environmental illumination without requiring external light sources. The photodetectors detect modulations in this self-provided light, enabling operation across varying light conditions while maintaining measurement precision through the differential detection of light patterns rather than absolute intensity.

Inventive Principle:
Principle #25Self-service

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

Enables precise, real-time measurement and visualization of aerodynamic flow on all aircraft surfaces, providing objective criteria for flow characterization and direction, overcoming limitations of previous techniques.

Implementation Method 1

said part, called movable part, being adapted to orient itself freely according to the local airflow, thus modulating the distribution of illuminance on said free surface

Methodology Applied
Scientific EffectLight modulation:

Implementation Method 2

an optical sensor configured to measure a distribution of illuminance on a free surface of said optical sensor

Methodology Applied
Scientific EffectPhotodetection: Photoelectric Effect

Data Source

PatentEP3144684B1Measurement of air flows along a wall
Publication Date: 2020.04.29 AIRBUS (SAS)
  • EP3144684B1 patent drawingFigure 1A~2
  • EP3144684B1 patent drawingFigure 3~4
  • EP3144684B1 patent drawingFigure 5A~6B

AI summary

The invention proposes to implement a simple, precise and real-time measurement device for airflows along a wall, and relates to a measurement device comprising: - an optical sensor (3) configured to measure a distribution of illuminance on a free surface of said optical sensor, and - a part (5) movably mounted on said optical sensor by partially covering its free surface, said part, called movable part (5), being adapted to orient itself freely according to the local airflow, thus modulating the distribution of illuminance on said free surface so that a current measurement by the optical sensor of the distribution of illuminance indicates the current orientation of said movable part, representative of the current airflow.