Turbine Blade Angular Position Detection Without Phonic Wheel

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Solution Overview

Problem

Monitoring the health and identifying individual blades in aeroengine rotor wheels, particularly those made of composite materials, is challenging due to the difficulty in detecting internal damage and unbalance, and existing methods require a phonic wheel which adds weight and complexity.

Innovation Solution

Detecting the angular positions of blades without a phonic wheel by using sensors on two sets of rotor wheels with distinct and prime numbers of blades, calculating time intervals between their passages to determine relative angular positions and identify each blade, allowing for damage detection and maintenance planning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a phonic wheel is integrated to detect beep per turn information, then the reference angular position can be obtained, but the weight of the aircraft increases and aerodynamic disturbances are introduced

Engineering Contradiction:

Improvereference angular position detectionVSAvoidaircraft weight

Core Design Contradiction:

Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent extracts the beep per turn detection function from the phonic wheel and relocates it to the blade itself by creating a singularity (excess or missing matter) on one blade. This eliminates the need for the separate phonic wheel component, thereby reducing aircraft weight and removing aerodynamic disturbances caused by the phonic wheel while maintaining reference angular position detection capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the beep per turn reference function with the blade structure by introducing a singularity on one blade. This combines the propulsion function of the blade with the reference detection function, eliminating the need for a separate phonic wheel and reducing overall system complexity and weight.

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If a phonic wheel is integrated to detect beep per turn information, then the reference angular position can be obtained, but the device complexity increases

Engineering Contradiction:

Improvereference angular position detectionVSAvoidintegration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the beep per turn detection function from the phonic wheel and relocates it to the blade itself by creating a singularity (excess or missing matter) on one blade. This eliminates the need for the separate phonic wheel component, thereby reducing aircraft weight and removing aerodynamic disturbances while maintaining reference angular position detection capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If composite material blades are used to improve performance and reduce weight, then the fan performance improves, but the detection of internal damage becomes more difficult

Engineering Contradiction:

Improvefan performanceVSAvoidinternal damage detection

Core Design Contradiction:

ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses mechanical vibration analysis through tip-timing sensors to detect internal damage in composite blades. By measuring the natural frequency of each blade and analyzing vibrational characteristics, the system can identify damage such as delamination that is not visible to the naked eye, enabling effective monitoring of composite blade health.

Inventive Principle:

Principle #18Mechanical vibration

Solution Approach 2:

The patent replaces visual inspection with a mechanical vibration-based detection system using tip-timing sensors. This substitution enables the detection of internal damage in composite blades through frequency analysis and vibrational pattern recognition, overcoming the limitation of visual inspection for non-transparent composite materials.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If tip-timing sensors are used to detect blade passage, then the natural frequency and state of health can be calculated, but the system requires precise blade identification

Engineering Contradiction:

Improveblade state of health measurementVSAvoidblade identification system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex optical or magnetic identification systems with a simple mechanical singularity (excess or missing matter) on one blade that creates a detectable beep per turn signal. This mechanical approach simplifies the identification system while enabling precise blade tracking and state of health measurement through tip-timing sensors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11268400B2Method and a system for detecting the angular position of blades of a turbine engine rotor wheel

Publication Date: 2022.03.08 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A method of detecting the angular positions of blades of a rotor wheel of a turbine engine, in which the turbine engine has first and second rotor wheels including respective first and second numbers of blades regularly distributed around their circumferences, includes: detecting the passage of each blade of the first wheel past a first sensor; detecting the passage of each blade of the second wheel past a second sensor; calculating the time intervals between the passage of a blade of the first wheel and the passages of each of the blades of the second wheel; and determining the relative angular position of each blade of the first wheel relative to the angular positions of the blades of the second wheel, the first number and the second number being distinct and mutually prime.