Stator Pocket Plasma Coating Repair for Gas Turbine Case Wear
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Solution Overview
Problem
Gas turbine engine stator cases experience wear, leading to inefficiencies and increased drag due to worn stator pockets, which existing repair methods struggle to address effectively, especially in complex geometries and multiple wear locations.
Innovation Solution
A method involving layer-by-layer nickel-aluminum plasma coating deposition into wear recesses of stator pockets, with precise machining and alignment to restore dimensional accuracy and flowpath integrity without welding, using a control system to manage the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is used to repair worn stator pockets, then structural strength is improved, but manufacturing precision and surface integrity deteriorate due to heat-affected zones and distortion
Solution Approach 1:
The patent replaces the thermal welding process with a mechanical/physical coating process. A coating material is applied to the worn stator pocket surface and then cured to form a hard, wear-resistant layer that restores the original dimensions and surface integrity without introducing heat-affected zones or thermal distortion.
Solution Approach 2:
The patent changes the material state through controlled curing parameters. The coating material transitions from a liquid or paste state to a solid, hardened state through controlled curing conditions (temperature, time, pressure), allowing precise control over the final surface properties and dimensions without the uncontrolled thermal effects of welding.
2Reliability
If conventional repair methods are used for complex geometry wear, then all wear locations can be addressed, but the number of operational steps and repair time increase significantly
Solution Approach 1:
The patent segments the repair process into distinct phases: surface preparation, coating application, and curing. This segmentation allows each phase to be optimized independently and enables efficient handling of complex geometries by treating different surface areas in a systematic manner rather than requiring multiple complex operations.
Solution Approach 2:
The patent performs preliminary surface preparation (cleaning, roughening, or priming) before coating application to ensure optimal adhesion and uniform coating distribution. This preliminary action prevents the need for rework and ensures that the coating process can efficiently address all wear locations in a single operation.
3Manufacturing precision
If multiple coating layers are deposited to restore dimensional accuracy, then manufacturing precision is improved, but the complexity of the repair process increases
Solution Approach 1:
The patent incorporates feedback mechanisms to monitor coating thickness and surface dimensions during the coating and curing process. This real-time feedback allows for precise control of multiple coating layers, ensuring dimensional accuracy is achieved without requiring overly complex manual intervention or inspection procedures at each stage.
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 method effectively restores the stator case to original specifications, minimizing operational steps and maintaining efficiency by addressing wear in complex geometries and multiple locations, thereby reducing drag and improving aerodynamic performance.
Implementation Method 1
A method may comprise receiving wear depths of a wear portion for each pocket in a plurality of pockets of a case; masking unworn portions of the stator pocket, grit blast and spray the worn portion with nickel coating using dual wire arc methods
Implementation Method 2
depositing the coating is performed in layers for the wear portion of each stator pocket; The coating may be a nickel-aluminum plasma coating
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A method for repairing a pocket of a case for a variable stator assembly may comprise: receiving, via a processor, a plurality of wear depths, each wear depth in the plurality of wear depths corresponding to a wear portion (328) in a stator pocket in a plurality of stator pockets (320); determining, via the processor, a plurality of thicknesses of a coating to be deposited based on the plurality of wear depths, each thickness of the coating in the plurality of thicknesses corresponding to the wear portion for each stator pocket in the plurality of stator pockets; and commanding, via the processor, a coating spray torch (608) to deposit the coating in the wear portion of each stator pocket in the plurality of stator pockets.