Gas Turbine Transmission for Variable Compressor Speed
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Solution Overview
Problem
Gas turbine engines face inefficiencies due to the need for turbine and compressor rotors to rotate over a large range of speeds to meet varying power demands, particularly during low power conditions, which limits engine efficiency.
Innovation Solution
A gas turbine engine with a transmission system featuring alternate transmission paths and an actuation mechanism that allows selection of different fixed transmission ratios, enabling the low pressure compressor rotor to maintain optimal rotational speed while keeping the high pressure turbine sections at constant speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the turbine and compressor rotors rotate at a large range of speeds to meet varying power demands, then the engine can adapt to different power requirements, but the engine efficiency deteriorates especially during low power conditions
Solution Approach 1:
The patent implements a variable transmission system that dynamically changes the transmission ratio based on operating conditions. The transmission mechanism includes selectable transmission paths with different ratios, allowing the system to adapt the speed relationship between turbine and compressor rotors according to power demands, thereby maintaining optimal efficiency across different operating regimes.
Solution Approach 2:
The invention changes the transmission ratio parameter to resolve the contradiction. By providing multiple transmission paths with different fixed ratios and selecting the appropriate ratio based on operating conditions, the system optimizes the relationship between rotor speeds and power output, preventing energy loss during low power conditions while maintaining adaptability.
2Loss of energy
If the low pressure compressor rotor rotates at optimal speed for efficiency, then engine efficiency improves, but the ability to meet varying power demands deteriorates
Solution Approach 1:
The variable transmission system dynamically adjusts the speed relationship between the low pressure compressor rotor and the power shaft based on actual power demands. This allows the compressor rotor to operate at optimal speeds for efficiency while the system as a whole adapts to varying power requirements through transmission ratio changes.
Solution Approach 2:
The transmission mechanism acts as an intermediary between the power shaft and the low pressure compressor rotor. It decouples the direct speed relationship, allowing the compressor rotor to maintain optimal rotational speed for efficiency while the transmission system accommodates varying power demands through different transmission ratios.
3Device complexity
If a fixed transmission ratio is used, then the transmission system is simple, but the ability to optimize engine efficiency across different operating conditions deteriorates
Solution Approach 1:
The transmission system transitions from a fixed ratio to a variable ratio configuration. The actuation mechanism enables selection of different transmission paths with different ratios, allowing the system to optimize engine efficiency across different operating conditions while maintaining relatively simple individual transmission paths.
Solution Approach 2:
The transmission system is designed to perform multiple functions through a single integrated mechanism. The same transmission system provides different fixed ratios for different operating conditions, making it universally applicable across the entire operating range without requiring separate transmission systems for each condition.
Data Source
AI summary
A gas turbine engine with a transmission having a first rotatable member coupled to an engine spool, a second rotatable member coupled to a compressor rotor, and coupled rotatable members defining at least first and second alternate transmission paths between the first and second members. Each transmission path defines a different fixed transmission ratio of a rotational speed of the second member on a rotational speed of the first member.