Linear Array Probe for Turbine Blade Inspection
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Solution Overview
Problem
The inaccessibility and small size of the internal spaces within gas turbine engines, particularly between and among turbine blades, make conventional camera-based inspection systems ineffective for identifying defects due to low light conditions and limited contrast, hindering detailed visualization of turbine blades without disassembly.
Innovation Solution
A method and system utilizing an elongated probe with a one-dimensional pixel array extending along the probe length, positioned radially within the turbine, which captures intensity-based signals from a line image area and converts them into cohesive two-dimensional digital images, synchronized with rotor rotation, enhancing contrast sensitivity and defect identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional camera system is used for in-situ inspection of turbine blades, then the inspection can be performed without disassembly, but the image quality and defect identification capability are limited due to low light conditions and low contrast
Solution Approach 1:
The patent transitions from two-dimensional camera imaging to one-dimensional linear array imaging, capturing intensity data along a single line that is then rotated and reconstructed to form defect images. This dimensional change enables superior contrast sensitivity in low-light conditions by measuring intensity variations along the blade length without requiring wide-area illumination.
Solution Approach 2:
The patent replaces conventional camera-based optical imaging with a linear array sensor system that measures light intensity along a line and uses computational methods to reconstruct defect images. This substitution enables operation in low-light environments where conventional cameras fail to provide adequate contrast for defect detection.
2Measurement precision
If a linear array sensor is used to capture intensity-based signals, then contrast sensitivity is improved in low light conditions, but the system complexity increases compared to conventional cameras
Solution Approach 1:
The patent extracts only the essential imaging function needed for defect detection by using a one-dimensional linear array instead of a two-dimensional camera sensor. This extraction simplifies the optical system while maintaining or improving measurement precision, as the linear array captures only the intensity variations along the blade length that are critical for defect identification.
Solution Approach 2:
The patent changes the fundamental imaging parameter from two-dimensional spatial capture to one-dimensional intensity measurement along a line. This parameter change enables superior contrast sensitivity by focusing measurement resources on detecting subtle intensity variations along the blade, while the reduced dimensional data requirement simplifies the overall system architecture.
3Area of stationary object
If the pixel array length is increased to cover the full blade length, then the inspection coverage is improved, but the probe size and insertion difficulty increase
Solution Approach 1:
The patent uses a one-dimensional linear array positioned radially across the blade path, capturing intensity data along a line rather than requiring a two-dimensional sensor array that would need to cover the entire blade surface. This dimensional approach provides sufficient inspection coverage for defect detection while maintaining a compact probe form factor that can be inserted through access ports.
Solution Approach 2:
The patent positions the linear array probe radially outward from the casing to intercept the rotating blade, allowing the sensor to remain stationary while the blade rotates through the measurement zone. This preliminary positioning strategy enables full blade length inspection coverage without requiring the probe itself to be as long as the blade, thereby facilitating easier insertion through access ports.
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 improved visualization and identification of turbine blade defects by providing high sensitivity to low contrast light conditions, facilitating detailed inspection without disassembly, and generating clear two-dimensional digital images for analysis.
Implementation Method 1
receiving at the pixel array energy emitted from an image area defined by a line extending along the component
Data Source
AI summary
A method of inspecting a component located on a rotor rotating about an axis internal to a turbine. An elongated probe is provided defining a probe length and having a one-dimensional pixel array formed by a plurality of pixels extending single file along the probe length. The probe is positioned through an access port in a casing of the turbine. The rotor is rotated to move the component past the pixel array, and energy emitted from an image area defined by a line extending along the component is received at the pixel array. An intensity-based signal from each pixel in the pixel array is conveyed to a processor to convert the intensity-based signals to an intensity-based line image, and a succession of the intensity-based line images are converted into a cohesive two-dimensional digital image of the component.