Split Seal Ring Design for Gas Turbine Sealing
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Solution Overview
Problem
Rotating seal rings in gas turbine engines face complex operational conditions due to centrifugal loading and thermal growth, leading to inefficiencies in sealing efficacy, particularly due to the formation of leak paths during axial movement and rotation.
Innovation Solution
A split seal ring design with conical split surfaces and a soft copper-aluminum coating, allowing for variable diameter expansion and maintaining continuous contact with both components to eliminate leak paths, forming a labyrinth seal and reducing sensitivity to orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a split seal ring is used to allow diameter variation during rotation, then the seal can follow rotor growth and maintain tight fit, but leak paths are formed during axial movement reducing sealing efficacy
Solution Approach 1:
The seal ring is divided into two segments with a split configuration, allowing independent movement of each segment. This segmentation enables the seal to accommodate both diameter changes during rotation and axial movement without forming continuous leak paths, as each segment can respond independently to different motion directions
Solution Approach 2:
A spring element is introduced as an intermediary between the two segments of the split seal ring. This spring mediator maintains continuous contact between segments while allowing relative movement, ensuring that the seal remains effective during both radial expansion and axial displacement without creating open leak paths
2Ease of operation
If the split plane is oriented to allow axial movement with the rotor, then the seal follows rotor movement, but the leak path forms around the free end reducing sealing effectiveness
Solution Approach 1:
The split seal ring employs asymmetric positioning of the split plane and free ends, where the free end is positioned to contact the groove surface during axial movement. This asymmetric configuration ensures that during axial displacement, the free end maintains contact with the groove, blocking leak paths while still allowing the seal to follow rotor movement
Solution Approach 2:
Different regions of the seal ring are given different functional properties: the main body follows rotor axial movement through friction, while the free end is specifically designed to contact the groove surface to seal leak paths. This local differentiation of function ensures both axial movement compatibility and sealing effectiveness are achieved simultaneously
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 solution enhances sealing effectiveness by eliminating open leak paths and maintaining tight contact under varying operational conditions, improving overall sealing efficiency and reducing assembly errors.
Implementation Method 1
During rotation (shown in FIG. 1), centrifugal force increases the diameter of the split seal ring 28, with the first and second free ends 28A and 28B moving relative to one another in a circumferential direction along the split plane 30
Implementation Method 2
At rest (not shown in FIG. 1), a spring force of the split seal ring 28 decreases its diameter
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A seal assembly (140) includes a first component (22), a second component (24) that defines an outer surface (146) and is located radially inward from the first component (22), a groove (26) defined in the second component (24) and arranged to face the first component (22), and a seal ring (128) positioned between the first and second components (22,24) and extending at least partially into the groove (26). The seal ring (128) defines an outer diameter surface (128C) and a first lateral surface (128E) adjoining the outer diameter surface (128C). The seal ring (128) is split to define a first free end (128A) and a second free end (128B), and the first and second free ends (128A,128B) are configured to overlap along a split surface (130) that extends from the first lateral surface (128E) to the outer diameter surface (128C).