Split Ring Rotor Seal for Gap Balance and Vibration Control
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Solution Overview
Problem
Gas turbine engine rotors face dimensional variations and non-axisymmetric deformations due to high-pressure, high-temperature conditions, leading to flow path geometry modifications that affect engine performance and induce vibrations, which existing structural means fail to adequately manage.
Innovation Solution
A gas turbine engine rotor assembly featuring a shaft with a groove and a surrounding disc, along with a split ring seal that is resiliently expandable to axially load the shaft, utilizing a complementary tapering profile to maintain a balanced gap and mitigate leakage paths, thereby stabilizing the rotor and enhancing sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a split ring seal is resiliently expanded across the gap to axially load the shaft, then sealing performance is improved, but the risk of non-axisymmetric deformation and vibration increases under high-pressure conditions
Solution Approach 1:
The split ring seal is designed with a non-uniform cross-sectional area distribution, creating asymmetric stress characteristics that promote axisymmetric deformation behavior under centrifugal loading, thereby reducing vibration and improving rotor stability while maintaining effective sealing
Solution Approach 2:
The seal's cross-sectional area parameter is strategically varied along its circumference, with increased area in specific regions to control deformation patterns and balance thermal-stress effects, transforming the seal's mechanical response under high-pressure conditions
2Stability of the object's composition
If the seal is designed to resiliently expand radially to maintain gap balance, then flow path geometry stability is improved, but the complexity of the seal structure increases
Solution Approach 1:
The seal incorporates localized variations in cross-sectional area at specific circumferential positions, allowing targeted control of gap clearance and flow path geometry without requiring complex structures throughout the entire seal circumference
Solution Approach 2:
The seal is designed to dynamically adjust its radial position through resilient expansion and contraction, allowing it to self-regulate gap clearance in response to changing operating conditions such as pressure and temperature variations
3Loss of energy
If the split ring seal is used to mitigate leakage paths, then engine efficiency is improved, but manufacturing precision requirements increase due to the tapering profile
Solution Approach 1:
The seal is pre-formed with the required tapering profile and cross-sectional area distribution during manufacturing, so that when installed and expanded, it automatically achieves the precise geometry needed for effective sealing without requiring post-installation adjustment
Solution Approach 2:
The seal's asymmetric cross-sectional design enables it to self-adjust its deformation characteristics under operating conditions, automatically compensating for manufacturing tolerances and achieving optimal sealing performance without external intervention
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 effectively axially loads the shaft, balances the gap flow, and reduces thermal bowing and vibration, improving the sealing performance and maintaining engine efficiency across varying operational conditions.
Implementation Method 1
the split ring resiliently expandable radially outwardly under centrifugal force relative to the axis to distance the end portions such that the first and second peripheral edges conform to a frustoconical shape of the gas turbine engine rotor disc
Data Source
AI summary
A gas turbine engine rotor assembly, comprising: a shaft about an axis having an outer surface radially outward and a groove radially into the outer surface; a disc surrounding the shaft rotatable with the shaft about the axis, the disc having an inner surface extending axially defining an inner diameter, having a disc profile around the groove and axially away from and radially inwardly of the inner diameter, the shaft and the disc defining a gap circumscribed outwardly by the inner diameter and inwardly by the outer surface; and a seal including a split ring fitted into the groove and rotatable with the shaft about the axis, the ring having a ring profile complementary to the disc profile, the ring resiliently expandable radially in the gap to the inner diameter, the disc profile cooperable with the ring profile to axially load the shaft via the ring expanded across the gap.