Hydrostatic Non-Contact Seal With Varied-Thickness Beams
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Solution Overview
Problem
Traditional contact seals in rotational equipment, such as gas turbine engines, generate excessive heat and internal stresses, leading to increased manufacturing and servicing costs due to the need for high-temperature materials, and result in higher mass and reduced efficiency.
Innovation Solution
A non-contact hydrostatic seal assembly utilizing varied thickness, curved or straight beams with spring elements and seal shoes that form a substantially annular end surface, allowing for a lighter configuration while maintaining sealing efficiency by adjusting the natural frequency of the seal shoes through geometric variations in the beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact seals with seal elements are used to seal gaps between rotors and stators, then sealing effectiveness is improved, but heat generation increases and efficiency decreases
Solution Approach 1:
The invention extracts the harmful contact interaction between seal elements and seal lands, replacing it with a non-contact hydrostatic seal mechanism. The seal shoes float on a hydrostatic film without contacting the rotor surface, eliminating friction and heat generation while maintaining sealing effectiveness through fluid pressure support.
Solution Approach 2:
The invention employs hydrostatic pressure from a fluid film to support the seal shoes away from the rotor surface, creating a non-contact sealing mechanism. The hydrostatic bearing principle uses pressurized fluid to maintain a stable gap, enabling sealing without mechanical contact and thus without heat generation.
2Reliability
If high temperature materials are used to accommodate high temperatures and stresses, then component durability is improved, but manufacturing and servicing costs increase
Solution Approach 1:
The invention replaces expensive high-temperature specialty materials with conventional, cost-effective materials. The non-contact seal design eliminates the need for heat-resistant alloys and ceramics, allowing the use of standard engineering materials that are easier and cheaper to manufacture and service.
3Reliability
If high temperature materials are used to accommodate high temperatures and stresses, then component durability is improved, but mass of the rotational equipment increases
Solution Approach 1:
The invention replaces heavy specialty high-temperature materials with lighter conventional materials. The non-contact seal mechanism eliminates the need for massively over-engineered components required to withstand contact stresses and high temperatures, reducing overall equipment mass.
4Weight of moving object
If varied thickness beams are used in the seal assembly, then mass of the seal is reduced, but structural strength may be compromised
Solution Approach 1:
The invention applies varied thickness to the beam structures, with thicker sections positioned at locations requiring higher strength and thinner sections where less structural support is needed. This localized variation in thickness optimizes the strength-to-weight ratio, reducing overall mass while maintaining necessary structural integrity.
Solution Approach 2:
The invention changes the geometric parameters of the beam structures, specifically varying the thickness dimension along the beam length. This parameter variation allows optimization of both mass and strength characteristics, creating a lightweight yet structurally sound seal assembly.
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 reduces the mass of the seal assembly while maintaining sealing efficiency and reducing the risk of high cycle fatigue and leakage, thereby lowering operational costs and improving the overall performance of rotational equipment.
Implementation Method 1
spring elements and seal shoes
Implementation Method 2
non-contact hydrostatic seal assembly
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A non-contact seal assembly (28) includes a plurality of seal shoes (54) arranged about a centerline (22) in an annular array. The seal shoes (54) include a first seal shoe (54) extending axially along the centerline (22) between a first shoe end (70) and a second shoe end (72). A seal base (52) circumscribes the annular array of the seal shoes (54). The assembly (28) also includes a plurality of spring elements (56), each of the spring elements (56) radially between and connecting a respective one of the seal shoes (54) with the seal base (52). Each of the spring elements (56) comprises a first beam (86a; 86d) having a first beam thickness and a second beam (86c; 86f) having a second beam thickness, where the first and second beam thicknesses are different.