Hydrodynamic Seal Groove Sets for Large Axial Translations
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Solution Overview
Problem
Conventional circumferential seals fail to maintain the hydrodynamic lifting force between a seal ring and a runner during large axial translations, leading to potential contact and wear, which compromises the seal's integrity and performance in high-performance turbine engines.
Innovation Solution
The implementation of a circumferential seal system with multiple groove sets along the outer circumference of the runner, where each groove set includes at least two grooves that exert a hydrodynamic lifting force on the seal ring, ensuring continuous communication of pressurized fluid and maintaining a thin film between the seal ring and the runner, even during axial excursions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional circumferential seals are used with a single groove configuration, then the structure is simple, but the hydrodynamic lifting force is lost during large axial translations causing seal contact and wear
Solution Approach 1:
The seal groove is divided into multiple separate groove sets (first groove set, second groove set, third groove set) positioned at different axial locations along the runner. Each groove set can independently generate hydrodynamic lifting force, ensuring that at least one groove set remains effective during large axial translations of the seal ring.
Solution Approach 2:
The invention extends the groove configuration from a single axial position to multiple axial positions along the runner circumference. This multi-dimensional arrangement ensures that regardless of the axial translation distance, the seal ring always overlaps with at least one functional groove set that can generate the necessary hydrodynamic lifting force.
2Reliability
If multiple groove sets are implemented along the runner circumference, then the lifting force is maintained during axial translations, but the manufacturing complexity increases
Solution Approach 1:
The groove system is segmented into multiple independent groove sets positioned at different axial locations. Each groove set functions as an independent sealing element, and the segmentation allows for modular manufacturing where each groove set can be fabricated and positioned separately, then assembled onto the runner.
Solution Approach 2:
Each groove set serves the universal function of generating hydrodynamic lifting force, but at different axial positions. This multi-functionality ensures that the seal system maintains reliability across the entire range of axial translations, as any groove set can compensate for the others during seal ring movement.
3Ease of operation
If the seal ring is allowed to contact the runner during translation, then the structure is simpler without lifting force mechanisms, but wear occurs compromising seal performance
Solution Approach 1:
The invention uses hydrodynamic pressure generated by fluid flow through the grooves to create a lifting force that separates the seal ring from the runner surface. This hydraulic lifting mechanism eliminates direct contact between the seal ring and runner, preventing wear and extending seal life while maintaining smooth operation throughout the seal's service life.
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 design enhances seal life by making the hydrodynamic grooves more resistant to wear and maintains the lifting force across the runner's translation path, preventing oil leakage and ensuring effective sealing between high and low pressure regions.
Implementation Method 1
Each groove set includes at least two grooves which either separately or jointly exert a hydrodynamic lifting force onto the inner diameter of the seal ring
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3~4
AI summary
A circumferential seal system for sealing a high pressure region (4) from a low pressure region (3) separated by a runner (20) with an outer circumferential surface (19) and a seal ring (6) disposed about the outer circumferential surface (19) is described. The seal system includes a plurality of groove sets (24a-24c) separately disposed along the outer circumferential surface (19). Each groove set (24a-24c) further includes at least two grooves (21). At least one groove (21) within each groove set (24a-24c) exerts a lifting force via a fluid from the high pressure region (4) onto the seal ring (6) as the runner (20) translates with respect to the seal ring (6) along an axis substantially perpendicular to the rotation of the runner (20) The continuous feed of fluid onto the seal ring (6) ensures a thin film between the seal ring (6) and the runner (20) regardless of their relative arrangement during axial excursions of the runner (20) resulting from conditions within a turbine engine.