Hydrostatic Seal Carrier Layout for Non-Contact Gap Control
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Solution Overview
Problem
Hydrostatic seals in gas turbine engines experience wear and friction issues due to contact between the seal shoe and aft plate, leading to reduced responsiveness to aerodynamic loads and potential binding, which affects the maintenance of small gaps between rotating and static components.
Innovation Solution
The hydrostatic seal assembly features a seal carrier with a radial outer wall and aft wall formed as a single unitary component, where the aft wall does not extend radially inwardly to the seal shoe position, allowing for non-contact operation with seal beams and incorporating stops to limit radial travel, thus eliminating wear and friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the seal shoe contacts the aft plate to maintain axial retention, then axial stability is improved, but wear and friction increase reducing responsiveness
Solution Approach 1:
The patent removes the harmful contact interface between the seal shoe and aft plate by extracting the retention function to a separate axial retention feature. This eliminates wear and friction while maintaining axial stability through the alternative retention mechanism.
Solution Approach 2:
The patent separates the axial retention function from the seal shoe structure itself, placing it on a distinct axial retention feature. This segmentation allows the seal shoe to operate without contact friction while axial retention is independently maintained by the separate feature.
2Force
If friction between seal shoe and aft plate is increased to prevent axial deflection, then axial retention is improved, but radial responsiveness deteriorates
Solution Approach 1:
The patent extracts the axial retention force generation from the seal shoe-aft plate contact interface and relocates it to the axial retention feature. This eliminates the friction that would otherwise oppose radial motion while maintaining the necessary axial retention force through the separate retention mechanism.
3Stability of the object's composition
If the aft wall extends radially inwardly to retain the seal support, then axial retention is improved, but contact with seal beams causes wear and binding
Solution Approach 1:
The patent removes the harmful radial extension of the aft wall that caused contact with seal beams. The retention function is extracted and redistributed to other features that do not interfere with seal beam operation, eliminating wear and binding while maintaining seal support retention.
Solution Approach 2:
The patent introduces non-contact retention mechanisms as intermediaries between the seal support and the rotating components. These intermediary features provide the necessary retention without direct mechanical contact, preventing wear and binding on the seal beams.
Data Source
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AI summary
A hydrostatic seal assembly (60) includes a primary seal (68) configured to maintain a selected gap (76) between the primary seal (68) and a rotating component (64). The primary seal (68) includes a seal support (104), a seal shoe (72), and one or more seal beams (74) operably connecting the seal support (104) to the seal shoe (74). The one or more seal beams (74) are configured as spring elements integral with the seal shoe (72) to allow radial movement of the seal shoe (72) relative to the seal support (104). A seal carrier (66) including a radial outer wall (110) is configured to radially position the primary seal (68). The seal carrier (66) is configured for a non-contact relationship with the seal shoe (72) during operation of the hydrostatic seal assembly (68).