Gas Turbine Rotor Spool Radial Offset Design
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Solution Overview
Problem
The existing methods for manufacturing and mounting low-pressure turbine rotor spools in gas turbine engines face challenges such as weight reduction, broaching limitations, installation difficulties, and inaccuracies due to the combination of rotor disks into a single spool, which leads to deformation and axial positioning issues.
Innovation Solution
A one-piece rotor spool with radially offset portions, featuring attachment means like teeth and recesses to prevent tangential movement and allow axial movement, enabling independent broaching and modular assembly, and a rotor ring with matching attachment features to transmit torque without increasing complexity, thus facilitating easy installation and reducing centrifugal force transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If rotor disks are combined into a single rotor spool to reduce weight, then the weight of the engine is reduced, but the broaching of grooves becomes impossible in certain portions
Solution Approach 1:
The rotor spool is divided into two radially offset portions: a downstream portion (radially outer) and an upstream portion (radially inner). This segmentation allows the broaching operation to be performed on the downstream portion while the upstream portion can be separately manufactured and later assembled, resolving the contradiction between weight reduction and manufacturability.
2Device complexity
If rotor disks are combined into a single rotor spool to eliminate inter-disk connecting means, then device complexity is reduced, but installation difficulty increases
Solution Approach 1:
By dividing the rotor spool into two portions that can be manufactured separately and then assembled, the invention maintains the simplicity of a single spool design while enabling easier installation. The two portions can be assembled in the engine without requiring complex disassembly or special installation procedures.
3Ease of manufacture
If rotor spool portions are connected by welding to enable independent broaching, then manufacturability is improved, but heat treatment deformation occurs
Solution Approach 1:
A rotor ring serves as an intermediary component that connects the upstream and downstream portions of the rotor spool. This intermediate element allows the portions to be joined without direct welding, thereby enabling independent broaching while avoiding the heat treatment and deformation issues associated with welding.
4Ease of manufacture
If rotor spool portions are connected by friction welding to improve manufacturability, then independent broaching is enabled, but axial positioning accuracy decreases
Solution Approach 1:
The rotor ring acts as a precision intermediary component with specifically designed attachment means that ensure accurate axial positioning of the upstream and downstream portions. This mechanical connection through the rotor ring provides superior positioning accuracy compared to friction welding.
Data Source
AI summary
A one-piece rotor spool for a gas turbine engine extending along the axis of the engine is disclosed. The spool includes an upstream portion and a downstream portion that are radially offset relative to one another. The radially outer downstream portion includes a plurality of housings for rotor blades formed in the outer surface of the radially outer downstream portion. The radially inner upstream portion includes an attachment mechanism designed to interact with a rotor ring in order to prevent a tangential movement of the rotor ring relative to the radially inner upstream portion.