Rotating Leaf Spring Seal for Radial Gap Variation Control
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Solution Overview
Problem
Existing seal assemblies in gas turbine engines face challenges in accommodating radial gap variations and managing centrifugal loading, leading to inefficiencies and increased leakage, particularly in rotating applications.
Innovation Solution
A rotating leaf spring seal design featuring a first annular ring, a hook section, and a spring section with angled annular rings, which includes a flex point and a hold down ring for sealing engagement with a tie shaft, accommodating radial expansion and providing a fluidic seal between rotating components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If static, non-rotating seal rings are used, then they are simple in structure and easy to manufacture, but they are unable to accommodate radial gap variations and permit more leakage
Solution Approach 1:
The seal ring is designed to rotate with the rotor, transforming from a static to a dynamic sealing solution. The rotating seal ring follows the radial expansion of the rotor, maintaining continuous sealing contact despite radial gap variations, thereby improving sealing performance while accepting increased operational complexity
Solution Approach 2:
The seal ring incorporates a compliant layer that changes its radial position in response to rotor expansion. This parameter change allows the seal to adapt to thermal and centrifugal effects, maintaining effective sealing under varying operating conditions without compromising manufacturability
2Adaptability or versatility
If rotating seal rings are used, then they can accommodate radial gap variations, but they are subject to significant centrifugal loading and experience greater stresses and loads
Solution Approach 1:
The seal ring is segmented into distinct functional layers: a rigid outer ring for structural support and a compliant inner layer for sealing. This segmentation allows the rigid portion to resist centrifugal loading while the compliant portion adapts to radial gap variations, resolving the strength-adaptability contradiction
Solution Approach 2:
The seal ring uses composite construction with a rigid substrate and a compliant coating or layered structure. The rigid material provides strength against centrifugal forces, while the compliant material enables adaptation to radial expansion, achieving both durability and sealing effectiveness
3Device complexity
If static seal rings are used, then they experience simpler operational conditions, but they require overlapping members to maintain proper position
Solution Approach 1:
The rotating seal ring is designed to maintain its position through self-centering mechanisms and proper mounting features that utilize the rotation itself to keep the seal properly positioned. The seal's geometry and mounting structure work together to automatically maintain correct positioning during rotation, eliminating the need for complex overlapping members
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 rotating leaf spring seal effectively manages radial gap variations and centrifugal loading, reducing leakage and maintaining a secure seal under high operational stresses, enhancing the operational efficiency of gas turbine engines.
Implementation Method 1
a spring section disposed between the first annular ring and the hook section
Implementation Method 2
Rotating seal rings, on the other hand, may be subject to significant centrifugal loading given the high rotational speeds that which gas turbine engines may operate
Data Source
AI summary
A rotating leaf spring seal is disclosed. In various embodiments, the rotating leaf spring seal includes a first annular ring configured for positioning against a support structure; a hook section having an outer surface configured for sealing engagement with a tie shaft and an inner surface configured for receiving a hold down ring; and a spring section disposed between the first annular ring and the hook section.