Hydrostatic Seal Assembly With Non-Contact Axial Retention
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Solution Overview
Problem
Hydrostatic seals in gas turbine engines experience wear and reduced responsiveness due to friction between the seal shoe and aft plate, leading to leakage and binding issues under aerodynamic loads.
Innovation Solution
A hydrostatic seal assembly with a primary seal and seal beams configured as spring elements, integrated with a seal shoe for radial movement, and a seal carrier with a radial outer wall for non-contact positioning, eliminating axial contact and wear surfaces to enhance responsiveness and reduce friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal shoe contacts the aft plate to maintain axial retention, then axial retention is improved, but wear and friction increase
Solution Approach 1:
The patent removes the aft plate contact surface from the seal assembly, eliminating the harmful friction and wear interface while maintaining axial retention through an alternative mechanism. The seal shoe is retained axially by the seal carrier structure without requiring a sliding contact surface, thus extracting the harmful friction element from the system.
Solution Approach 2:
The patent introduces a radial outer wall as an intermediary structure that provides axial retention for the seal shoe without creating a sliding friction interface. This mediator allows the seal shoe to maintain its axial position while eliminating the direct contact and friction that would occur with a traditional aft plate configuration.
2Reliability
If the seal shoe contacts the aft plate for axial retention, then axial retention is improved, but responsiveness to aerodynamic loads decreases
Solution Approach 1:
By removing the aft plate contact interface, the patent eliminates the frictional constraint that impedes the seal shoe's responsiveness to aerodynamic loads. The seal shoe can now respond more freely to radial aerodynamic forces while axial retention is maintained through the radial outer wall structure.
Solution Approach 2:
The radial outer wall acts as an intermediary that provides axial retention without interfering with radial movement responsiveness. This mediator structure allows the seal shoe to maintain axial position while remaining highly responsive to aerodynamic loads in the radial direction.
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 effectively maintains a selected gap between rotating and static components, reducing wear, friction, and binding, thereby improving the seal's responsiveness to aerodynamic loads and maintaining efficiency in gas turbine engines.
Implementation Method 1
The one or more seal beams are configured as spring elements integral with the seal shoe to allow radial movement of the seal shoe relative to the seal support
Implementation Method 2
Some hydrostatic seals are configured with a shoe having radial travel in response to a pressure differential across the seal
Data Source
AI summary
A hydrostatic seal assembly includes a primary seal configured to maintain a selected gap between the primary seal and a rotating component. The primary seal includes a seal support, a seal shoe, and one or more seal beams operably connecting the seal support to the seal shoe. The one or more seal beams are configured as spring elements integral with the seal shoe to allow radial movement of the seal shoe relative to the seal support. A seal carrier including a radial outer wall is configured to radially position the primary seal. The seal carrier is configured for a non-contact relationship with the seal shoe during operation of the hydrostatic seal assembly.