Floating Non-Contact Seal Beam Layout for Torsional Stiffness
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Solution Overview
Problem
High-pressure applications of floating, non-contact seals in aircraft engines require increased torsional stiffness to resist shoe twisting, but aerodynamic design constraints limit shoe size and natural frequency, necessitating stiffer beams without increasing stress.
Innovation Solution
The design involves beams that extend past the edge of the flowpath surface in a reference direction, increasing their width relative to the shoe, which enhances stiffness and natural frequency without impacting aerodynamic design, allowing for improved torsional control and clearance maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If beam width is increased to improve torsional stiffness, then shoe twisting resistance is improved, but aerodynamic design constraints are violated
Solution Approach 1:
The beam width in the axial direction (first width) is increased beyond the shoe width, creating a dimensional extension that provides additional torsional stiffness without increasing the radial profile. This allows the seal to achieve required stiffness while maintaining aerodynamic compatibility in the critical radial dimension.
Solution Approach 2:
The seal is divided into distinct functional segments: the shoe element that interfaces with the rotating component and the extended beam elements that provide structural stiffness. This segmentation allows each component to be optimized independently for its specific function.
2Strength
If shoe size is increased to improve stiffness, then torsional control is improved, but natural frequency constraints are violated
Solution Approach 1:
Instead of increasing shoe size in the radial direction, the beam width is extended in the axial direction. This dimensional change increases the moment of inertia and natural frequency without increasing the radial footprint of the shoe, thereby maintaining clearance requirements while improving torsional control.
3Strength
If beam stiffness is increased to resist shoe twisting, then pressure load resistance is improved, but stress levels increase
Solution Approach 1:
The beam width is increased in the axial direction rather than increasing material thickness or using higher-strength materials. This geometric change increases the area moment of inertia, providing greater resistance to bending and torsional stresses under pressure loads without increasing stress concentrations in the material.
Data Source
AI summary
Aspects of the disclosure are directed to a seal comprising: a shoe, and at least two beams coupled to the shoe, where a first width associated with the beams exceeds a second width associated with the shoe in a reference direction. Aspects of the disclosure are directed to an engine comprising: a compressor section, a turbine section, and a floating, non-contact seal that includes: a shoe, and at least two beams coupled to the shoe, where the beams extend past an edge of a flowpath surface associated with the shoe in a reference direction.