Non-intrusive Blade Pitch Measurement Using Optical Markers
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Solution Overview
Problem
Designing a measuring system for turbomachines with variable pitch propellers or fans is challenging due to complexity, temperature constraints, and the need for accurate pitch detection without mechanical interaction or electromagnetic interference, especially in experimental models.
Innovation Solution
A non-intrusive blade pitch measuring device using visual markers and an optical acquisition system to capture images of a pattern formed by markers on the blade and hub, allowing for accurate pitch measurement without mechanical interaction and minimizing electromagnetic signal emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sensors are used for pitch measurement, then accurate pitch detection is achieved, but integration becomes complicated due to temperature constraints and relative mobility of elements
Solution Approach 1:
The patent replaces conventional mechanical/electrical sensors with an optical measurement system. Visual markers are attached to the blade and platform, and their relative positions are captured using optical imaging. This substitution eliminates the need for complex sensor integration while maintaining measurement accuracy, as the optical system can operate remotely without being affected by temperature constraints or relative mobility issues that plague conventional sensors.
Solution Approach 2:
The patent creates visual copies (markers) of the blade and platform positions that can be captured and analyzed. Instead of directly measuring physical quantities with sensors, the system captures optical images of marker positions and processes these visual copies to determine pitch angle. This approach simplifies integration since the markers are passive visual elements that don't require complex electrical connections or calibration.
2Ease of operation
If wireless data transmission systems are used, then data acquisition is simplified, but electromagnetic interference increases due to multiple control and measuring devices operating simultaneously
Solution Approach 1:
The patent replaces wireless electromagnetic data transmission with optical imaging and processing. The measurement system captures pitch information through optical images of visual markers and processes these images locally to determine pitch angle. This eliminates the need for wireless transmission of data from rotating components, thereby reducing electromagnetic interference in the measurement environment while maintaining ease of data acquisition through optical means.
3Measurement precision
If internal measuring systems are used in the fan, then measurement accuracy is improved, but design and production difficulty increases due to high system complexity and numerous moving parts
Solution Approach 1:
The patent extracts the measurement function from the internal fan system and places it external to the rotating assembly. Visual markers are attached to the blade and platform, but the measurement is performed by an external optical system that captures images of these markers. This extraction eliminates the need to integrate complex measuring devices within the fan, simplifying both design and production while maintaining measurement accuracy through optical observation of marker positions.
4Measurement precision
If mechanical interaction between measuring device and blade is established, then direct measurement is achieved, but measurement intrusiveness increases
Solution Approach 1:
The patent replaces mechanical interaction with optical observation. Instead of using mechanical sensors that physically contact the blade, the system attaches visual markers to the blade and platform and uses optical imaging to capture their relative positions. This non-contact optical measurement achieves direct pitch measurement without mechanical intrusiveness, eliminating wear, friction, and interference with blade operation while maintaining measurement accuracy.
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 high-accuracy pitch measurement of rotating blades with minimal electromagnetic interference, simplifying the design and integration of the measuring system and allowing simultaneous measurement of multiple blades during operation.
Implementation Method 1
at least one optical acquisition device, the optical acquisition device being configured to capture an image of the pattern so as to deduce the pitch of the blade from the image of the pattern
Data Source
AI summary
A blade pitch measuring device of an un-ducted fan of a turbomachine, the fan including a hub, at least one platform rotatable with respect to the hub and at least one blade mounted on the platform, the device includes at least one first visual marker attached to the platform, at least one second visual marker attached to the hub, the first and the second visual marker forming a pattern which evolves depending on the pitch of the blade, and at least one optical acquisition device, the optical acquisition device being configured to capture an image of the pattern so as to deduce from it the pitch of the blade.