Gas Turbine Spool Assembly Multiple Torque Paths
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Solution Overview
Problem
Gas turbine engines face overspeed issues due to mechanical failure of spool components, leading to potential structural failure of turbine disks and blades, which necessitates the use of heavier, more robust components to mitigate risks.
Innovation Solution
Implementing a spool assembly with multiple torque paths, where a thrust bearing supports the shaft at the intersection of these paths, allowing torque transfer from one path to continue even if a component in another path fails, thereby preventing turbine overspeed by ensuring at least one load path remains operational.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single torque path is used to connect the turbine to the compressor and gear assembly, then the structure is simpler and uses fewer components, but mechanical failure of any component in the torque path causes turbine overspeed and potential structural failure
Solution Approach 1:
The spool assembly is divided into a first spool segment connecting the turbine to the compressor, and a second spool segment connecting the turbine to the gear assembly. These segments are coupled to a common shaft at different locations, creating separate torque paths. This segmentation ensures that mechanical failure in one segment does not affect the other torque path, preventing turbine overspeed while maintaining structural integrity.
2Reliability
If heavier, more robust turbine disks and blades are used to accommodate overspeed conditions, then structural failure is prevented, but the engine weight increases and efficiency decreases
Solution Approach 1:
By segmenting the torque paths through separate spool segments, the system prevents overspeed conditions from occurring in the first place. This eliminates the need for oversized, heavy turbine disks and blades designed to withstand extreme overspeed, allowing for lighter, more efficient components that operate within normal speed parameters.
Solution Approach 2:
The multiple torque path configuration acts as a preliminary protective measure that prevents overspeed conditions before they can occur. By having redundant torque paths established in advance, the system proactively avoids the need for heavy-duty components designed for worst-case scenarios.
3Force
If the thrust bearing is located at the connection between the first spool segment and the shaft, then axial loads are properly supported, but the structure becomes more complex with multiple connection points
Solution Approach 1:
The thrust bearing positioned at the first spool segment connection serves multiple functions: it supports axial loads from both the compressor torque path and provides a stable mounting point for the segmented spool assembly. This multi-functional positioning simplifies the overall structure by combining load support and structural attachment at a single location.
Data Source
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AI summary
Systems and methods involving multiple torque paths of gas turbine engines are provided. In this regard, a representative spool assembly for a gas turbine engine (100), which incorporates a compressor (102), a turbine (106) and a gear assembly (138), includes: a shaft (108) operative to be driven by the turbine; a first spool segment (120) operative to couple the shaft to the compressor; and a second spool segment (122) operative to couple the shaft to the gear assembly. The first spool segment is operative to load the turbine engine despite a mechanical failure of the second spool segment, and the second spool segment is operative to load the turbine despite a mechanical failure of the first spool segment.