Optical Probe Blade Deformation Measurement
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Solution Overview
Problem
Conventional methods for measuring longitude deformation of aircraft turbine blades at high temperatures and rotational speeds are impractical due to thermal drift, short sensor lifespan, and interference with aerodynamic characteristics, limiting their effectiveness and applicability.
Innovation Solution
An optical monitoring method using an optical probe with a precision servo motor, synchronized rotation sensor, and optic-electric conversion module to collect and process radiation signals, allowing real-time analysis of blade deformation without direct contact, thereby overcoming thermal and aerodynamic limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauge is fixed on blade surface or ends to measure longitude deformation, then measurement can be achieved, but thermal drift and short sensor lifespan occur under high temperature conditions
Solution Approach 1:
The patent replaces mechanical strain gauges with an optical measurement system that uses laser radiation and photoelectric detection to measure blade deformation. The optical probe emits laser beams that reflect off the blade surface, and the reflected light is detected by photodetectors to calculate deformation, eliminating the need for physical contact sensors that suffer from thermal drift and short lifespan.
Solution Approach 2:
The patent introduces laser radiation as an intermediary between the measurement system and the blade. Instead of directly attaching sensors to the blade, the system uses laser beams that can penetrate and reflect off the blade surface without physical contact, allowing measurement through the intermediate medium of light radiation.
2Measurement precision
If strain gauge is mounted on blade to measure deformation, then measurement is possible, but weight and volume of sensors compromise aerodynamic characteristic
Solution Approach 1:
The patent replaces heavy mechanical strain gauges with a lightweight optical measurement system. The optical probe and photodetectors have minimal weight and volume compared to traditional strain gauge mounting systems, thereby preserving the aerodynamic characteristics of the blade while enabling precise deformation measurement.
3Measurement precision
If contact deformation measuring method is used on rotating blade, then measurement can be obtained, but difficulty in lead and wiring occurs
Solution Approach 1:
The patent replaces contact-based measurement methods that require lead and wiring with a non-contact optical system. The laser beams and reflected light carry measurement information without requiring physical connections, eliminating the complexity of lead and wiring on rotating blades.
Solution Approach 2:
The patent creates an optical copy or representation of the blade surface deformation through laser reflection. Instead of physically connecting sensors to the rotating blade, the system captures optical information that replicates the deformation state, allowing measurement without physical attachment or wiring.
4Measurement precision
If optical probe is driven deep into casing to collect radiation, then accurate blade deformation measurement is achieved, but thermal environment exposure increases
Solution Approach 1:
The patent uses laser radiation as an intermediary that can traverse the thermal environment without being affected by it. The optical probe measures deformation by detecting reflected laser beams from the blade surface, allowing accurate measurement while the probe itself remains thermally isolated from the high-temperature region.
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 accurate, real-time measurement of blade deformation under high-temperature and high-speed conditions, extending sensor lifespan and improving aerodynamic performance by reducing weight and volume, while maintaining precision and reliability.
Implementation Method 1
The temperature between the blades is lower than the temperature of the blades while the blades rotating in high speed propelled by high temperature gas and the heat radiation from the rotational blade is collected by the optical probe mounted on the engine cover
Implementation Method 2
The optical probe is driven deep into the casing to collect radiations which are transferred to the optic-electric conversion module through optical fibers. The radiations are converted to electric signals for following data processing
Data Source
AI summary
The present invention discloses a method of measuring longitude deformation of blades. The radiation and rotation speed of the blade are collected by an optical probe and a synchronized rotation sensor. The stretch of the blade is able to be determined by the obvious change in the light intensity detected by the optical probe. The precision servo motor keeps driving the optical probe to move upward. The collected radiation is compared with the radiation collected on the previous point. The stretch of the blade is calculated based on position of the blade tip which is determined by the time when the high level radiation from the blade is disappeared. The longitude deformation of the blade is calculated by plugging the stretch into the deformation equation. Mapping the calculated deformation with the number of the blade calculated with rotation speed synchronizing signals to achieve the deformation of all the blades.