Gas Turbine Seal Panel Cantilever Design for Weight Reduction
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Solution Overview
Problem
Existing seal panels in gas turbine engines face weight penalties due to their large size required to counteract rearward loading, which can lead to premature wear and lifting issues, as they need to be positioned radially further away from the engine axis to achieve sufficient forward loading.
Innovation Solution
A seal panel design featuring a rotor portion with a cantilever and a stator portion, allowing the seal to be placed closer to the rotor, reducing the size and weight while maintaining effective forward biasing through pressurized air, thereby offsetting rearward loading on the shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the seal panel is positioned radially further away from the engine axis to achieve sufficient forward loading, then the forward loading capability is improved, but the size and weight of the seal panel increase
Solution Approach 1:
The seal panel incorporates a cantilever structure that allows dynamic positioning and adjustment of the seal location. This enables the seal to be placed optimally close to the rotor while the cantilever provides the necessary mechanical advantage to generate sufficient forward loading force, resolving the contradiction between seal position and loading effectiveness.
Solution Approach 2:
The invention changes the structural parameters of the seal panel by introducing a cantilever mechanism with specific geometric ratios. This allows the seal to operate at a different radial position (closer to rotor) while maintaining the required loading parameters through the mechanical leverage provided by the cantilever structure.
2Force
If the seal panel is positioned radially further away from the engine axis to achieve sufficient forward loading, then the forward loading capability is improved, but the radial distance and area of the seal panel increase
Solution Approach 1:
The cantilever structure transforms the static seal panel into a dynamic mechanical system that can generate amplified forces through its lever arm. This allows the seal to be positioned with minimal area close to the rotor while the cantilever's mechanical advantage provides the necessary forward loading capability.
Solution Approach 2:
The cantilever acts as an intermediary mechanical element between the seal and the engine structure. It transmits and amplifies forces, allowing the seal to operate with reduced area while still achieving the required forward loading through the cantilever's mechanical leverage.
3Force
If a large conventional seal is used to provide sufficient forward loading, then the forward loading capability is improved, but the weight penalty increases
Solution Approach 1:
The invention replaces a large static seal with a compact dynamic seal coupled to a cantilever mechanism. The cantilever provides mechanical advantage that allows a smaller, lighter seal to generate the same forward loading force that would otherwise require a large conventional seal.
Solution Approach 2:
The invention substitutes a purely mechanical large-area seal system with a combined mechanical-cantilever system. The cantilever provides force multiplication, replacing the need for a large seal area and thereby reducing the overall weight of the sealing system.
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 design achieves a significant weight saving while effectively offsetting rearward loading on the shaft, potentially prolonging the service life of thrust bearings by allowing the seal to be positioned closer to the rotor, reducing the size and weight of the seal panel.
Implementation Method 1
the carrier 44 and seal 42 provide a sealed chamber which can be pressurised with air from a compressor. This air is at a higher pressure than the ambient air which surrounds the fan hub on the upstream side of the seal panel. Thus, in use, the relatively high pressure air provides a forward load or bias on the seal panel
Data Source
AI summary
Described is a shaft support system for a gas turbine engine comprising: a rotatable fan shaft; first and second support structures extending in parallel from the shaft to a load bearing structure to provide radial location of the shaft within an engine casing, wherein the first support and second support structures include first and second respective mechanical fusible joints; wherein the first fusible joint is a two-stage fuse which partially fails within a first predetermined load range, the second fusible joint fails within a second predetermined load range which is different to the first load range, and the first fusible joint fully fails only when the second fusible joint has failed.