Axial Offset Abradable Seal for Centrifugal Compressor Leakage
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Solution Overview
Problem
Centrifugal compressors experience leakage flow between the stator and rotor due to differential axial pressure, which affects the overall operating efficiency and is not adequately reduced by existing abradable seals.
Innovation Solution
A sealing system with a spring mechanism that facilitates axial positioning control of the stator seal relative to the rotor, creating an axial gap and utilizing a secondary seal to minimize leakage, achieved through a pressure-activated mechanism that adjusts the seal position based on pressure differentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional abradable seal is used between stator and rotor, then the seal structure is simple, but leakage flow is not adequately reduced
Solution Approach 1:
The seal assembly is made dynamically adjustable through a spring mechanism that allows axial movement of the stator seal relative to the rotor seal. This dynamic positioning enables the seal to adapt to varying operating conditions and pressure differentials, optimizing the sealing gap to minimize leakage flow while maintaining structural feasibility
Solution Approach 2:
The invention introduces axial positioning control as a new dimension of adjustment beyond the traditional radial sealing approach. By controlling the axial relative position between stator and rotor seals, the system creates an optimized sealing configuration that reduces leakage without requiring complex radial adjustments
2Productivity
If the seal clearance is reduced to improve efficiency, then stage efficiency increases, but the risk of rotor harm increases
Solution Approach 1:
The abradable material is applied locally to the stator seal surface in specific regions where contact with rotor teeth occurs. This localized abradable coating allows controlled material removal to maintain optimal clearance while protecting the rotor from damage, as the stator seal absorbs wear instead of the rotor
Solution Approach 2:
The spring mechanism pre-positioned in the seal assembly provides a cushioning effect that maintains optimal clearance before contact occurs. This preliminary positioning prevents excessive clearance that would reduce efficiency while avoiding conditions that would cause rotor damage through uncontrolled contact
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 significantly reduces leakage flow by maintaining a minimal sealing gap, optimizing compressor stage efficiency and performance, and is applicable to both new and existing compressors.
Implementation Method 1
a first spring disposed between the stator and the seal and configured to facilitate axial movement of the seal relative to the seal housing
Implementation Method 2
rotor teeth configured to create rub grooves within the abradable portion
Implementation Method 3
rotor teeth configured to create rub grooves within the abradable portion
Data Source
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AI summary
A sealing system (200) for a centrifugal compressor includes a stator (220) having a seal housing (230), a seal (223) disposed in the seal housing (230) and having an abradable portion (225) along an inner circumference, a rotor (210) having a plurality of rotor teeth (215) configured to rotate within the inner circumference of the seal (223) and configured to create rub grooves (227) within the abradable portion (225), and a first spring (240) disposed between the stator (220) and the seal (210) and configured to facilitate axial movement of the seal (223) relative to the seal housing (230).