Differential Turbine Drive for High-Pressure Compressor Speed Matching
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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 impact overall engine performance.
Innovation Solution
A method and system that utilize a differential system and augmentation system within the gas turbine engine to distribute power between the high pressure turbine stages and compressor, allowing for selective application and extraction of auxiliary power through motor-generators, enabling the high pressure compressor to operate at a speed greater than the second stage turbine's limitations, thereby optimizing efficiency and reducing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the high pressure compressor is directly connected to the high pressure turbine via a common high speed spool, then the turbine can drive the compressor, but the compressor cannot operate at its optimal design speed due to turbine rotational speed limits
Solution Approach 1:
The high pressure turbine is segmented into two independent stages, each capable of rotating at different speeds. The first stage turbine rotates at higher speed while the second stage rotates at lower speed, allowing the compressor to be driven at optimal speed through gear mechanism while turbine blades operate within stress limits
Solution Approach 2:
A gear mechanism is introduced as an intermediary between the turbine and compressor. The gear system converts the rotational motion from turbine stages into appropriate speed for the compressor, enabling speed transformation without direct coupling
2Strength
If the second stage turbine rotational speed is limited by centrifugal stress, then blade integrity is maintained, but the high pressure compressor efficiency is reduced due to speed mismatch
Solution Approach 1:
The system dynamically adjusts the operational parameters of each turbine stage independently. The first stage operates at higher rotational speed while the second stage operates at lower speed within stress limits, with the gear mechanism dynamically transmitting power to maintain compressor at peak efficiency point
Solution Approach 2:
The rotational speed parameter is changed and optimized for each turbine stage separately. By operating the first stage at higher speed and second stage at lower speed, the system achieves both blade strength requirements and compressor efficiency requirements through parameter optimization
3Productivity
If the first stage turbine efficiency is lower than the second stage, then the second stage can operate more efficiently, but the overall turbine performance is limited by the weaker first stage
Solution Approach 1:
Each turbine stage is designed with local quality optimization tailored to its specific operational conditions. The first stage is designed for higher speed operation with corresponding blade geometry, while the second stage is optimized for lower speed with different blade characteristics, allowing each stage to operate at its local efficiency maximum
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
This configuration allows the high pressure compressor to operate at a higher efficiency and speed, reducing fuel power requirements and enhancing engine performance without exceeding centrifugal stress limits, while enabling efficient power distribution and storage during various operational phases.
Implementation Method 1
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
Implementation Method 2
selectively applying an auxiliary input power into at least one of the high pressure compressor spool and the high pressure turbine
Implementation Method 3
driving a high pressure turbine having a first stage and a second stage with an exhaust stream from a combustor
Implementation Method 4
driving a high pressure compressor connected to a high pressure compressor spool
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.