Rotary Seal Ring Structure for Thermal Expansion and Eccentricity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rotary machines with existing sealing devices suffer from reduced sealing performance due to thermal expansion in the axial direction and radial eccentricity, leading to increased pressure loss and decreased efficiency.
Innovation Solution
A sealing device featuring a sealing ring with free-cutting material having convex and concave portions, radial fins, and oblique fins that maintain gap distance and prevent contact, ensuring stable sealing performance even with thermal expansion and eccentricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If abradable seals are provided in rounded corner regions facing compressor impellers, then sealing performance is improved, but the seals are cut by blades during operation due to thermal expansion and eccentricity, causing gap enlargement and sealing performance deterioration
Solution Approach 1:
The sealing ring is divided into multiple segments along the axial direction, with each segment having convex and concave portions that create a stepped configuration. This segmentation allows the seal to accommodate axial displacement and thermal expansion without compromising the sealing gap, as each segment can independently adjust to maintain contact with the blade tips.
Solution Approach 2:
The invention introduces axial dimension variations through convex and concave portions on the sealing ring surface, transforming a simple radial seal into a three-dimensional stepped seal. This axial dimensionality allows the seal to compensate for thermal expansion and eccentricity by providing varying radial clearances at different axial positions, thereby maintaining stable sealing performance under operational variations.
2Reliability
If the sealing ring contacts the oblique fin during thermal expansion, then sealing gap is maintained, but the oblique fin may break due to excessive contact stress
Solution Approach 1:
The oblique fin is designed with a specific geometric configuration and material selection that provides inherent cushioning capability. The fin's inclined surface and controlled thickness allow it to absorb contact stress from the sealing ring during thermal expansion without exceeding its strength limits, preventing breakage while maintaining sealing effectiveness.
Solution Approach 2:
The invention optimizes the oblique fin's geometric parameters (angle, thickness, length) and material properties to balance its dual function of maintaining sealing gap and withstanding contact stress. By carefully controlling these parameters, the fin can deform elastically under thermal expansion conditions to maintain contact with the sealing ring while remaining within safe stress limits to avoid breakage.
Data Source
AI summary
A sealing device seals a gap between an outer circumferential surface of a rotor and an inner circumferential surface of a stator. The sealing device includes a sealing ring provided on the stator and having a free-cutting material, in which a convex portion and a concave portion are alternately formed in an axial direction, on a surface facing the rotor; a plurality of radial fins protruding radially outward from the outer circumferential surface of the rotor; and oblique fins which obliquely protrude from the outer circumferential surface of the rotor toward both ends of the free-cutting material of the sealing ring in the axial direction from the outside of the both ends.