Variable Speed Gear Controller for Three-Spool Turbofan
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Solution Overview
Problem
Gas turbine engines face limitations in achieving optimal thermal, transfer, and propulsive efficiencies, particularly in rotating speeds of turbine and compressor sections, which affect overall engine performance.
Innovation Solution
A gas turbine engine design incorporating a first gear system driven by a low shaft, a second gear system driven by an intermediate shaft, and a gear controller that varies the effective speed reduction of both systems to optimize the rotation of the fan and compressor sections, with gear reduction ratios greater than 2.3, allowing for independent control of fan and compressor speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed gear system is used to drive the fan and compressor sections, then the speed reduction ratio is fixed, but the engine cannot optimize performance across different operational conditions
Solution Approach 1:
The patent applies the dynamics principle by making the gear system adjustable rather than fixed. The controllable means (such as variable geometry mechanisms or adjustable gear ratios) allow the speed reduction ratio to change dynamically based on operational conditions, enabling the engine to optimize fan and compressor speeds for different flight regimes while managing system complexity through controlled adjustability.
2Productivity
If the fan and compressor sections rotate at fixed speeds, then the mechanical structure is simple, but the engine cannot achieve optimal thermal and propulsive efficiencies
Solution Approach 1:
The patent applies parameter changes by enabling variation of rotational speeds of the fan and compressor sections through the controllable means. This allows optimization of thermal efficiency (through compressor speed adjustment) and propulsive efficiency (through fan speed adjustment) independently, achieving better overall engine performance while managing complexity through targeted parameter control.
3Adaptability or versatility
If separate drive systems are used for fan and compressor sections, then independent speed optimization is possible, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing a controllable means that can regulate speed reduction ratios for both the fan drive gear system and compressor drive gear system. This multi-functional approach allows independent speed optimization of fan and compressor sections while using a unified control mechanism, thereby reducing overall system complexity compared to entirely separate drive systems.
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 design enhances propulsive efficiency by optimizing the speeds of the fan and compressor sections, improving engine performance by allowing for tailored speed adjustments based on operational conditions, thereby increasing thrust and reducing fuel consumption.
Implementation Method 1
a first gear system, a second gear system, and a controllable means for varying the speed reduction provided by both gear systems
Implementation Method 2
a first gear system driven by a low shaft, a second gear system driven by an intermediate shaft
Data Source
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AI summary
A turbofan engine is disclosed that includes a fan rotatable about an axis, a compressor section including a high pressure compressor, a medium pressure compressor and a low pressure compressor and a turbine section including a high pressure turbine, an intermediate turbine and a fan drive turbine. A fan drive gear system is driven by the fan drive turbine for driving the fan. A compressor drive gear system is driven by the intermediate turbine for driving the low pressure compressor. A gear controller controls rotation of at least one of the fan drive gear system and the compressor drive gear system relative to a static structure to vary an effective speed reduction ratio of one of the fan drive gear system and the compressor drive gear system.