Variable Vane Case Coating for Flow Path Wear Repair
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Solution Overview
Problem
Gas turbine engines with variable stator vanes experience wear on the flow path surface, leading to reduced efficiency and increased drag due to the formation of wear recesses, which can cause misalignment of vanes and increased friction, necessitating effective repair methods to restore the surface dimensions.
Innovation Solution
A method and system for repairing the flow path surface of a gas turbine engine case involves measuring wear depth, machining to remove lips if present, and applying a nickel-aluminum plasma coating using a double-wire feed and plasma arc additive manufacturing process to restore the surface to its original dimensions, ensuring the coating thickness matches the wear depth, and using a control system with a gauge and coating spray torch to align and apply the coating accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If variable stator vanes are used to optimize compressor operability, then compressor efficiency is improved, but wear to the flow path surface occurs
Solution Approach 1:
The patent applies parameter changes by modifying the flow path surface through coating application. The coating thickness parameter is specifically controlled to match the wear depth at each location, transforming the degraded surface back to its original dimensional specifications and restoring compressor efficiency while maintaining surface integrity.
Solution Approach 2:
The patent recovers the flow path surface by removing worn material through machining and then restoring the surface through coating application. This process discards the damaged surface layer and recovers the original surface dimensions and properties, extending the component life while maintaining the benefits of variable stator vane operation.
2Loss of substance
If wear recesses are allowed to form, then material loss occurs, but machining to remove lips increases manufacturing complexity
Solution Approach 1:
The patent applies local quality by measuring wear depth at multiple specific locations within the wear recess and applying coating with locally varied thickness. Each location receives coating thickness corresponding to its specific wear depth, ensuring precise restoration without unnecessary material removal or complex multi-step machining operations.
Solution Approach 2:
The patent applies preliminary action by measuring wear depths at all locations before coating application and planning the coating thickness distribution in advance. This preliminary measurement and planning step simplifies the subsequent coating process, avoiding the need for complex iterative machining operations to achieve the correct surface profile.
3Manufacturing precision
If coating thickness is increased to cover wear depth, then surface restoration is improved, but coating application precision requirements increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the coating thickness parameter based on measured wear depth at each location. The coating thickness is set to be equal to or greater than the wear depth at each specific point, ensuring complete coverage while maintaining precision through location-specific parameter optimization rather than uniform thick coating throughout.
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 flow path surface dimensions, reducing wear-related efficiency losses and drag, extending the life of the engine by ensuring optimal vane alignment and minimizing friction, thereby improving the operational efficiency of the gas turbine engine.
Implementation Method 1
applying a coating to the wear recess using a double-wire feed and plasma arc additive manufacturing process
Implementation Method 2
The coating is a nickel-aluminum plasma coating
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A method (600) for repairing a flow path surface (84) of a case (82) for a variable vane assembly (80) includes measuring (606) a wear depth (D2) at a location within a wear recess (98) formed in the flow path surface (84) of the case (82), determining a coating thickness (T) corresponding to the wear depth (D2) at the location, and repairing the flow path surface (84) of the case (82) by applying (614) a coating (114) to the wear recess (98), where the coating (114) has the coating thickness (T) at the location.