Seal Arc Segment Notch Design for Gas Turbine Leakage
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Solution Overview
Problem
Gas turbine engines face inefficiencies due to gas leakage around the blades, which current abradable seal designs fail to adequately address, leading to reduced performance and increased wear.
Innovation Solution
A seal arc segment with a recessed portion and notch design, formed by machining, using ceramic materials and metallic mating components to prevent circumferential rotation and maintain precise positioning, thereby reducing gas leakage and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If abradable seal designs are used to reduce radial gap with blade tips, then gas leakage is reduced, but circumferential rotation and positioning precision deteriorate
Solution Approach 1:
The seal is divided into multiple arc segments that can be independently positioned and secured. Each segment includes features like notches and retention members that enable precise circumferential positioning while maintaining the abradable sealing function for reducing gas leakage.
Solution Approach 2:
The seal arc segment incorporates asymmetric features including a notch with a flat surface on one side and curved surfaces on other sides. This asymmetric geometry prevents circumferential rotation by providing a unique mating interface with the mounting structure, ensuring precise positioning while maintaining sealing effectiveness.
2Loss of energy
If abradable seal designs are used to reduce radial gap with blade tips, then gas leakage is reduced, but wear increases
Solution Approach 1:
The seal arc segment combines abradable material in the sealing surface for effective gas leakage prevention with hardened or reinforced regions at the mounting interface and retention features. This local differentiation allows the sealing portion to be soft and conformable while the structural portions resist wear and maintain positioning precision.
Solution Approach 2:
The seal assembly uses composite construction with ceramic seal arc segments that provide both abradable sealing surfaces and wear-resistant structural elements. The combination of different material properties within the same component enables simultaneous achievement of low gas leakage and high wear resistance.
3Manufacturing precision
If notching and recessed portions are added to prevent rotation, then positioning precision is improved, but device complexity increases
Solution Approach 1:
The notch and recessed portions are integrated into the seal arc segment as unified features rather than separate components. The notch serves dual purposes of positioning and preventing rotation, while the recessed portion accommodates retention members that secure the segment to the mounting structure, reducing overall assembly complexity.
Solution Approach 2:
The notched recessed portion structure performs multiple functions simultaneously: it provides circumferential positioning, prevents rotation through the flat surface engagement, and facilitates secure mounting through retention members. This multi-functionality reduces the need for additional separate positioning and securing components.
Data Source
AI summary
A seal arc segment includes a body including a radially inner surface and a radially outer surface. The radially inner surface and the radially outer surface are located between a first circumferential end and a second circumferential end. A recessed portion defines a cavity in the radially outer surface. A notch is located in an edge of the recessed portion adjacent the first circumferential end.