Optical Blade Lockup Detection in Gas Turbines
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Solution Overview
Problem
In gas turbines, seal pins can migrate and become wedged between blade platforms during turning gear operations, leading to blade lockup, which causes uneven spacing and increased mechanical stress due to reduced centrifugal force, making it difficult to detect locked blade assemblies effectively.
Innovation Solution
An optical measurement system that includes a light source to illuminate blade surfaces, a video device to capture images as blades rotate, and a controller to detect pixel intensity and spacing changes, indicating locked blade assemblies by identifying changes in the distance between consecutive blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If seal pins are used to form seals between adjacent rotating blade assemblies, then sealing effectiveness is improved, but the risk of pin migration and blade lockup increases
Solution Approach 1:
The patent replaces mechanical inspection methods with an optical measurement system using laser light and video imaging to detect blade spacing changes, enabling non-contact detection of blade lockup conditions without mechanical interference
Solution Approach 2:
The patent introduces an optical intermediary system (laser light and video device) that mediates between the blade assembly and detection mechanism, allowing indirect measurement of blade spacing through light reflection and image analysis
2Difficulty of detecting and measuring
If traditional mechanical inspection methods are used to detect blade lockup, then detection capability is limited, but inspection time and costs increase
Solution Approach 1:
The patent replaces mechanical inspection tools and procedures with an optical measurement system that uses laser illumination and video imaging to detect blade spacing anomalies, significantly reducing inspection time and enabling more sensitive detection
Solution Approach 2:
The patent changes the detection parameter from mechanical contact measurement to optical parameter measurement (pixel intensity and spacing in video images), enabling faster and more precise detection of blade lockup conditions
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
The system accurately detects locked blade assemblies by analyzing pixel intensity and spacing changes, allowing for early identification of blade lockup and reducing inspection time and costs, even during turning gear operations.
Implementation Method 1
at least one light source for emitting light that impinges on a blade surface of each blade in a row of blade assemblies
Data Source
AI summary
An optical measurement system for detecting at least one locked blade assembly in a gas turbine. The system includes at least one light source for emitting light that impinges on a blade surface of each blade in a row of blade assemblies. The system also includes a video device for imaging the blades as the blades rotate about the center axis. Further, the system includes a controller for controlling operation of the light source and video device. The controller detects a pixel intensity associated with each blade and a spacing between each pixel intensity wherein a change in spacing between consecutive pixel intensities indicates that a distance between consecutive blades has changed relative to the first distance thereby indicating at least one locked blade assembly.