Gas Turbine Rotor Disk High-Speed Design
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Solution Overview
Problem
Gas turbine engine rotor disks face challenges in operating at higher speeds and temperatures, requiring improvements in thermal, weight, and propulsive efficiencies.
Innovation Solution
The design and fabrication of rotor disks with specific diameter ratios (D/W, OD/D, d/D) between 1.25 and 3.15, allowing for optimized structural support and performance at high rotational speeds and temperatures, including the formation of lugs for blade mounting and use of materials like nickel-based alloys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rotor disks operate at higher speeds and temperatures to improve engine efficiency, then power density and operational efficiency improve, but structural integrity and reliability deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the bore diameter to outer diameter ratio within a specific range (0.35-0.45) and controlling material microstructure parameters (acicular martensite with specific grain size and distribution). These parameter optimizations enable the rotor disk to withstand higher rotational speeds and temperatures while maintaining structural integrity, thus resolving the contradiction between improved power density and maintained reliability
Solution Approach 2:
The patent utilizes composite material structures by combining nickel-based superalloy with controlled microstructural phases (acicular martensite and gamma prime precipitates). This composite microstructure provides both the strength needed for high-speed operation and the thermal resistance required for high-temperature durability, thereby enabling higher power density without sacrificing structural reliability
2Temperature
If rotor disk material strength is increased to withstand higher temperatures and speeds, then operational temperature and speed limits improve, but weight increases
Solution Approach 1:
The patent controls material parameters including alloy composition (nickel-based with specific element ranges), heat treatment parameters (solution treatment temperature and aging conditions), and microstructure parameters (acicular martensite grain size and gamma prime precipitate distribution). These optimized parameters achieve high-temperature strength without excessive weight gain, as the controlled microstructure provides strength-to-weight efficiency
Solution Approach 2:
The patent implements local quality through radial variation in microstructure and material properties across the rotor disk thickness. The live rim region has optimized material composition and microstructure for high-speed centrifugal loads, while the bore region has different properties for thermal and mechanical coupling. This localized optimization allows high operational temperatures without uniformly increasing the entire disk weight
3Speed
If rotor disk geometry is optimized for high-speed operation, then rotational speed capability improves, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes geometric parameters including the bore to outer diameter ratio (0.35-0.45), live rim thickness, and lug geometry within specific ranges. These parameter optimizations enable high-speed operation while maintaining manufacturability through conventional forging and machining processes, avoiding excessive manufacturing complexity
Solution Approach 2:
The patent employs preliminary action by performing near-net-shape forging to closely approximate the final rotor disk geometry before machining. The forging process pre-establishes the optimized bore diameter, outer diameter, and live rim thickness, reducing subsequent machining operations and tooling complexity while achieving the high-speed optimized geometry
Data Source
AI summary
A rotor disk for a gas turbine engine is disclosed and formed to enable operation at high rotational speeds in a high temperature environment. The rotor disk is formed to include a bore, a live rim diameter and an outer diameter related to each other according to defined relationships.