Multistage Turbine Differential Drive for Compressor Speed and Blade Stress
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Solution Overview
Problem
Gas turbine engines face challenges in maximizing the competing efficiencies and design speeds of high pressure compressors and turbines, particularly due to rotational speed limitations and efficiency disparities between the first and second stages of the high pressure turbine, which affect overall engine performance.
Innovation Solution
A method and system that utilize a differential system and augmentation system within the gas turbine engine to manage power distribution by connecting the high pressure turbine stages to the compressor stages through motor-generators, allowing for selective input and extraction of auxiliary power, thereby optimizing rotational speeds and efficiencies across the engine components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the high pressure turbine second stage is designed to rotate at high speeds to match compressor design speed, then the compressor efficiency is improved, but the turbine blades exceed maximum allowable centrifugal stress limits
Solution Approach 1:
The high pressure turbine is divided into two independent stages, each capable of rotating at different speeds. The first stage rotates at a lower speed to handle the bulk of the power extraction, while the second stage rotates at a higher speed to match the compressor's design speed, thereby improving compressor efficiency without over-stressing the turbine blades.
Solution Approach 2:
The patent introduces a differential mechanism that allows the first and second stages of the high pressure turbine to rotate at different speeds dynamically. This dynamic speed differentiation enables the system to optimize both turbine blade stress and compressor efficiency simultaneously, as the speed ratio between stages can be adjusted based on operating conditions.
2Use of energy by moving object
If the high pressure turbine first stage is designed to extract more energy to reduce fuel power requirements, then fuel consumption is reduced, but the turbine efficiency of the first stage decreases compared to the second stage
Solution Approach 1:
By segmenting the turbine into two stages with different rotational speeds, the system optimizes energy extraction distribution. The first stage operates at lower speed with moderate efficiency, while the second stage operates at higher speed with higher efficiency, achieving an overall balance that reduces fuel power requirements while maintaining acceptable total turbine efficiency.
Solution Approach 2:
The patent changes the operational parameters of the turbine stages by allowing different rotational speeds. This parameter differentiation enables the first stage to operate under conditions that reduce fuel power requirements, while the second stage operates at optimized conditions for maximum efficiency, thus resolving the contradiction between fuel reduction and efficiency maintenance.
3Device complexity
If a common high speed spool connects the high pressure compressor and high pressure turbine, then the system structure is simplified, but the competing efficiencies and design speeds of the compressor and turbine cannot be maximized
Solution Approach 1:
The spool system is segmented into a common high speed spool and a second stage spool that are connected through a differential mechanism. This segmentation allows the common spool to maintain structural simplicity while the differential connection enables independent speed optimization of the turbine stages, thus maximizing overall engine efficiency without significantly increasing structural complexity.
Solution Approach 2:
The differential mechanism acts as an intermediary between the common high speed spool and the second stage spool. This intermediary component allows the two spools to rotate at different speeds while maintaining a mechanical connection, thereby enabling independent optimization of compressor and turbine speeds without requiring completely separate drive systems.
Data Source
AI summary
A method of distributing power within a gas turbine engine is disclosed. In various embodiments, the method includes driving a high pressure turbine having a first stage and a second stage with an exhaust stream from a combustor, the first stage connected to a high pressure turbine first stage spool and the second stage connected to a high pressure turbine second stage spool; driving a high pressure compressor connected to a high pressure compressor spool via a differential system, the differential system having a first stage input gear connected to the high pressure turbine first stage spool, a second stage input gear connected to the high pressure turbine second stage spool and an output gear assembly connected to the high pressure compressor spool; and selectively applying an auxiliary input power into at least one of the high pressure compressor spool and the high pressure turbine.