Hydrostatic Seal with Backup Labyrinth for Gas Turbine Pressure Control
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Solution Overview
Problem
Labyrinth seals in gas turbine engines deteriorate over time due to thermal and mechanical growths, assembly tolerances, and engine loads, leading to increased flow consumption and thermodynamic cycle losses, and carbon seal faces are prone to damage from pressure fluctuations and vibrations.
Innovation Solution
A seal assembly comprising a hydrostatic seal with a mounting bracket and a back-up labyrinth seal, where the labyrinth seal has a land and knife edge configuration to maintain pressure differential in both normal and failure modes, with the hydrostatic seal interacting during normal operation and the back-up seal taking over in case of failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a labyrinth seal is used to maintain pressure differential, then the seal can be simple in structure, but the seal deteriorates over time due to thermal and mechanical growths leading to increased flow consumption
Solution Approach 1:
The seal system is divided into two independent segments: a primary hydrostatic seal and a secondary labyrinth seal. Each segment performs sealing function independently, allowing the system to maintain reliability even when one segment deteriorates. The hydrostatic seal uses a seal face and seal runner that create a hydrostatic barrier, while the labyrinth seal provides an alternative path restriction.
Solution Approach 2:
The patent implements a backup sealing mechanism (labyrinth seal) that is预先 positioned to take over when the primary hydrostatic seal deteriorates. This beforehand cushioning ensures that pressure differential maintenance is not compromised by thermal and mechanical growths affecting the primary seal over time.
2Reliability
If a hydrostatic seal is used to maintain pressure differential, then the seal effectiveness is improved, but the device complexity increases due to additional components
Solution Approach 1:
The patent merges two different sealing mechanisms (hydrostatic seal and labyrinth seal) into a single integrated seal assembly. The hydrostatic seal face and runner are positioned to work in conjunction with the labyrinth seal structures, creating a unified system that leverages the advantages of both approaches while managing complexity through integration.
Solution Approach 2:
The seal assembly is designed to perform multiple functions: the hydrostatic seal provides primary pressure differential maintenance during normal operation, while the labyrinth seal structures provide both secondary sealing and structural support. The arms and mounting brackets serve dual purposes of positioning and structural reinforcement.
3Reliability
If carbon seal face is used in hydrostatic seal, then the seal face provides good sealing properties, but it is prone to damage from pressure fluctuations and vibrations
Solution Approach 1:
The patent positions the labyrinth seal structures and arms to provide mechanical support and cushioning to the carbon seal face before damage can occur. The arms holding the seal face and runner are designed to absorb and distribute mechanical stresses from vibrations and pressure fluctuations, protecting the brittle carbon material from direct impact loads.
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 maintains pressure differential in gas turbine engines by ensuring continuous operation even when the primary hydrostatic seal fails, reducing parasitic losses and preventing damage to the seal faces.
Implementation Method 1
a hydrostatic seal having a seal face and a seal runner, wherein interaction of the seal face and the seal runner maintains a pressure differential within the gas turbine engine
Implementation Method 2
a back-up seal, wherein the back-up seal is a labyrinth seal having a land and a knife edge, the knife edge being operative to interact with the land to form a seal
Data Source
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AI summary
Gas turbine engine systems involving hydrostatic face seals (150) with back-up seals (170) are provided. In this regard, a representative seal assembly for a gas turbine engine includes: a hydrostatic seal (150) having a seal face (152) and a seal runner (154); and a back-up seal (170); wherein; in a normal mode of operation of the hydrostatic seal (150), interaction of the seal face (152) and the seal runner (154) maintains a pressure differential within the gas turbine engine and, in a failure mode of operation of the hydrostatic seal (150), the back-up seal (170) maintains a pressure differential within the gas turbine engine.