Curved Spring Beam Non-Contact Seal for Thin Annular Gaps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing seal assemblies for rotational equipment, such as gas turbine engines, face challenges in efficiently sealing annular gaps between rotor and stationary structures while minimizing size and weight, as they often require increased radial thickness to maintain effective sealing, which can limit flexibility and material usage.
Innovation Solution
A non-contact seal assembly featuring a hydrostatic primary seal device with spring elements having non-straight centerlines that follow the curvature of seal shoes, combined with secondary seal devices, to maintain uniform airgaps and reduce overall thickness, allowing for longer seal shoes and spring beams with reduced stiffness and operational stresses, enabling the use of lower-cost materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional straight spring beams are used in seal assemblies, then the radial thickness must be increased to maintain effective sealing, but this increases the overall size and weight of the equipment
Solution Approach 1:
The spring beams are designed with non-straight, curved centerlines that follow the curvature of the seal shoes. This curvature allows the spring beams to maintain contact and sealing effectiveness while occupying less radial space, directly resolving the contradiction between sealing reliability and radial thickness.
Solution Approach 2:
The invention changes the geometric parameter of the spring beam from a straight centerline to a non-straight centerline with specific curvature. This parameter change enables the spring beam to achieve the same sealing function with reduced radial dimensions, addressing both sealing effectiveness and size constraints.
2Volume of moving object
If shorter seal shoes and spring beams are used to reduce radial thickness, then the stiffness increases and operational stresses increase, but this limits material selection and increases cost
Solution Approach 1:
The curved centerline of the spring beam creates a more favorable stress distribution pattern compared to straight beams. The curvature allows longer beam lengths with reduced stiffness, lowering operational stresses and enabling the use of lower-cost materials while maintaining reduced radial thickness.
Solution Approach 2:
By changing the centerline geometry from straight to curved, the invention alters the mechanical properties of the spring beam, specifically reducing stiffness and operational stresses. This enables the use of longer, thinner beams made from lower-cost materials, resolving the contradiction between radial thickness and stress levels.
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
This configuration effectively seals annular gaps with reduced radial thickness, enabling longer seal shoes and spring beams, decreasing internal stresses and allowing for the use of alternative materials, while maintaining sealing performance and reducing the size and weight of the equipment.
Implementation Method 1
spring elements having non-straight centerlines that follow the curvature of seal shoes, combined with secondary seal devices, to maintain uniform airgaps and reduce overall thickness
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An assembly (10) includes a plurality of seal shoes (42), a seal base (40) and a plurality of spring elements (44). The seal shoes (42) are arranged around an axis (12) in an annular array. The seal base (40) circumscribes the annular array of the seal shoes (42). Each of the spring elements (44) is radially between and connects a respective one of the seal shoes (42) to the seal base (40). A first of the spring elements (44) includes a first mount (70), a second mount (72) and a spring beam (74A). The first mount (70) is connected to the first seal shoe (42). The second mount (72) is connected to the seal base (40) and disposed a circumferential distance away from the first mount (70). The spring beam (74A) extends longitudinally along a non-straight centerline (80A) between and connected to the first mount (70) and the second mount (72).