Labyrinth Seal Insulation Layer for Thermal Clearance Control
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Solution Overview
Problem
Labyrinth-type seal assemblies in gas turbine engines face lubricant leakage due to thermal gradients between sealing parts, leading to inefficient sealing and potential increased clearances.
Innovation Solution
Incorporating an insulation layer, such as an air gap, between the seal stator and the housing to thermally insulate the seal stator from the lubricant, matching thermal expansions and reducing operational clearances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a labyrinth seal is used to seal between the housing and the rotatable shaft, then sealing is provided, but thermal gradients between the seal stator and seal rotor cause lubricant leakage
Solution Approach 1:
An insulation layer is introduced as an intermediary element between the seal stator and the housing. This insulation layer acts as a thermal mediator that reduces heat transfer from the lubricant to the seal stator, thereby minimizing thermal gradients between the seal stator and seal rotor, and preventing lubricant leakage while maintaining sealing effectiveness
Solution Approach 2:
The thermal parameters of the seal system are modified by introducing the insulation layer. This changes the thermal conductivity and heat transfer characteristics between the lubricant and seal stator, altering the temperature distribution and reducing thermal expansion differences that cause leakage
2Strength
If the seal stator is in direct contact with the housing, then structural support is provided, but thermal expansion mismatch increases operational clearances
Solution Approach 1:
The insulation layer serves as a thermal intermediary that decouples the thermal expansion behavior of the seal stator from the housing. This allows the seal stator to maintain its structural support function while experiencing reduced thermal influence from the lubricant, thereby minimizing clearance variations
Solution Approach 2:
The invention addresses thermal expansion mismatch by introducing the insulation layer that reduces heat transfer to the seal stator. This minimizes differential thermal expansion between the seal stator and seal rotor, maintaining tighter operational clearances and preventing lubricant leakage
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 reduces lubricant leakage and maintains optimal sealing efficiency by matching thermal growth of seal rotor and stator components, improving air/oil system performance and reducing heat input to the oil system.
Implementation Method 1
an insulation layer between the seal stator and the housing, the insulation layer composed of a material different than those used for the seal stator and the housing
Implementation Method 2
matching thermal expansions and reducing operational clearances
Data Source
AI summary
A labyrinth seal assembly for a gas turbine engine having a rotatable shaft. The labyrinth seal assembly has: a housing defining a cavity for receiving a lubricant; a labyrinth seal between the housing and the rotatable shaft of the gas turbine engine, the labyrinth seal having a seal rotor securable to the rotatable shaft and a seal stator secured to the housing; and an insulation layer between the seal stator and the housing, the insulation layer composed of a material different than those used for the seal stator and the housing.