Variable Transmission Gas Turbine Engine Speed Control
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Solution Overview
Problem
Gas turbine engines face efficiency limitations due to varying power demands, which cause low pressure spools and associated rotors to operate at suboptimal rotational speeds, especially during low power conditions, affecting overall engine performance.
Innovation Solution
A gas turbine engine design featuring independently rotatable low and high pressure spools with a variable transmission that adjusts the rotational speed of the low pressure compressor rotor, allowing for a fixed ratio between the low pressure spool and turbine, and a variable transmission ratio between the compressor and spool to maintain optimal operational efficiency across power demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the low pressure spool rotates the low pressure compressor rotor through a fixed ratio connection, then the structure is simple, but the compressor rotor cannot operate at optimal speed under varying power demands
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed ratio connection with a variable ratio transmission system. The variable ratio transmission allows the rotational speed ratio between the low pressure spool and compressor rotor to be dynamically adjusted based on operating conditions, enabling the compressor rotor to operate at optimal speed across varying power demands while the spool maintains fixed speed for stability.
2Power
If the core section rotors rotate at a large range of speeds to meet varying power demands, then the power demand requirements are met, but the rotational speed of the low pressure turbine and spool is limited, affecting engine efficiency
Solution Approach 1:
The patent applies segmentation by dividing the engine into independent speed control zones: the high pressure spool and core section rotors operate at variable speeds to meet power demands, while the low pressure spool maintains fixed speed, and the compressor rotor achieves optimal speed through variable ratio transmission. This segmentation allows each component to operate in its optimal speed range independently.
Solution Approach 2:
The variable ratio transmission acts as an intermediary between the low pressure spool and the compressor rotor. It decouples the speed relationship between these components, allowing the spool to rotate at fixed speed while the compressor rotor rotates at optimal speed, thereby preventing energy loss that would occur if both had to rotate at variable speeds.
3Adaptability or versatility
If the low pressure compressor rotor is directly connected to the low pressure spool, then the device complexity is low, but the compressor rotor speed cannot be independently optimized
Solution Approach 1:
The patent implements dynamics by introducing a variable ratio transmission system that allows the rotational speed ratio between the low pressure spool and compressor rotor to be dynamically adjusted. This enables independent optimization of compressor rotor speed while maintaining a relatively simple transmission structure compared to multi-stage gear 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 enables the low pressure compressor rotor to operate at desired speeds independently of other rotors, optimizing engine efficiency and maintaining high pressure section speed consistency across power demand variations, improving fuel consumption and operational performance.
Implementation Method 1
rotating at least one rotor of a low pressure turbine with a flow of exhaust gases from the high pressure turbine section
Data Source
AI summary
A gas turbine engine including at least one high pressure turbine rotor and at least one high pressure compressor rotor drivingly engaged to a rotatable high pressure spool, a low pressure spool rotatable independently of the high pressure spool, at least one low pressure turbine rotor drivingly engaged to the low pressure spool, and a rotatable load drivingly engaged to the low pressure spool. A fixed rotational speed ratio is defined between rotational speeds of the at high pressure turbine and compressor rotors. A fixed rotational speed ratio is defined between rotational speeds of the low pressure turbine rotor(s) and of the low pressure spool. A low pressure compressor rotor is in driving engagement with the low pressure spool through a variable transmission which defines a variable rotational speed ratio between the rotational speeds of the low pressure spool and of the low pressure compressor rotor.