Blade Outer Air Seal Plug Assembly for Gas Turbine Sealing
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Solution Overview
Problem
Existing methods for sealing core run-out openings in blade outer air seal (BOAS) segments of gas turbine engines, such as brazing or plug welding, are costly, require skilled labor, and may not provide consistent performance due to reliance on heat treatment and surface preparation.
Innovation Solution
A plug assembly comprising a cup and wedge mechanism that expands into a press fit within the core run-out opening, eliminating the need for brazing and providing a robust seal without the need for extensive surface preparation or high-temperature processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brazing or plug welding is used to seal core run-out openings, then sealing performance is achieved, but manufacturing cost increases and skilled labor is required
Solution Approach 1:
The patent replaces thermal processes (brazing/welding) with a mechanical interference fit system. A plug with a tapered outer surface is inserted into a corresponding tapered bore in the BOAS segment, creating a press-fit mechanical seal that eliminates the need for costly thermal joining processes and skilled welding/brazing labor.
2Reliability
If brazing or plug welding is used to seal core run-out openings, then sealing is achieved, but the process requires skilled labor and heat treatment
Solution Approach 1:
The invention substitutes complex thermal processes (surface preparation, heating, brazing/welding, cooling) with a simple mechanical insertion process. The tapered plug is directly pressed into the tapered bore, creating a consistent interference fit seal that does not require skilled labor or complex heat treatment equipment.
3Reliability
If traditional sealing methods are used, then openings are sealed, but extensive surface preparation and high-temperature processing are required
Solution Approach 1:
The patent replaces high-temperature thermal processing with ambient-temperature mechanical assembly. The interference fit between the tapered plug and tapered bore creates a robust seal through mechanical contact pressure alone, eliminating the need for high-temperature brazing or welding operations.
Solution Approach 2:
The invention changes the fundamental parameter from thermal energy input to mechanical force input. By using a tapered geometry that converts insertion force into radial contact pressure, the system achieves sealing through mechanical parameters rather than thermal parameters, operating at ambient temperature instead of high temperature.
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 plug assembly offers a cost-effective, efficient, and reliable sealing solution that is less dependent on skilled labor and heat treatment, while providing higher temperature capability and consistent performance compared to traditional methods.
Implementation Method 1
A plug assembly comprising a cup and wedge mechanism that expands into a press fit within the core run-out opening
Data Source
Figure 1
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Figure 4
AI summary
A plug assembly (62) includes a cup (70) which defines a cup portion (74) and a cup anti-liberation portion (76) along an axis. A wedge (72) is mountable within the cup portion (74) to at least partially radially expand the cup anti-liberation portion (76). This retains the cup (70) within an opening (60).