Compressor Area Ratio for High Pressure Gas Turbine Engines
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Solution Overview
Problem
The high pressure compressor rotor in gas turbine engines faces challenges in achieving high pressure ratios due to high stresses and temperatures, particularly at the downstream end, limiting overall pressure ratio and efficiency.
Innovation Solution
The implementation of a gear reduction system that allows the fan drive turbine rotor to drive the fan rotor at slower speeds, while the high pressure turbine rotor drives the high pressure compressor rotor, with specific flow cross-sectional area ratios between compressor rotors to optimize work distribution and efficiency, enabling higher pressure ratios and temperature capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the high pressure compressor rotor operates at high speeds to achieve high pressure ratios, then the pressure ratio increases, but the temperature and stresses at the downstream end become excessively high
Solution Approach 1:
The compressor system is divided into low pressure and high pressure compressor rotors with distinct functional responsibilities. The low pressure compressor handles the initial compression stages while the high pressure compressor handles subsequent stages, allowing each to operate within optimal temperature and stress ranges while achieving high overall pressure ratios
Solution Approach 2:
The patent implements independent speed control for the high pressure compressor rotor through a separate turbine drive, allowing dynamic optimization of operating speeds to maintain optimal temperature and stress conditions while achieving high pressure ratios
2Stress or pressure
If the high pressure compressor rotor operates at high speeds to achieve high pressure ratios, then the pressure ratio increases, but the stresses at the downstream end become excessively high
Solution Approach 1:
The compressor system is divided into low pressure and high pressure compressor rotors with distinct functional responsibilities. The low pressure compressor handles the initial compression stages while the high pressure compressor handles subsequent stages, allowing each to operate within optimal temperature and stress ranges while achieving high overall pressure ratios
Solution Approach 2:
The patent implements independent speed control for the high pressure compressor rotor through a separate turbine drive, allowing dynamic optimization of operating speeds to maintain optimal temperature and stress conditions while achieving high pressure ratios
3Use of energy by moving object
If a gear reduction system is implemented to allow the fan drive turbine to rotate at slower speeds, then the fan can operate more efficiently, but the device complexity increases
Solution Approach 1:
The turbine system is segmented into a fan drive turbine and a high pressure compressor drive turbine, with the latter connected through a gear reduction system. This allows independent optimization of each turbine's operating characteristics, improving overall fuel efficiency despite the added mechanical complexity
Solution Approach 2:
A gear reduction system acts as an intermediary between the fan drive turbine and the high pressure compressor rotor, enabling speed matching and optimal power transfer while allowing each component to operate at its most efficient speed
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 achieves higher overall pressure ratios and improved temperature capability at the high pressure compressor rotor, enhancing fuel efficiency and reducing fuel burn in long-range aircraft, while maintaining efficient operation of both low and high pressure compressor rotors.
Implementation Method 1
it has been proposed to include a gear reduction such that the fan can rotate at slower speeds than the fan drive turbine rotor
Implementation Method 2
the high pressure turbine rotor drives the high pressure compressor rotor
Implementation Method 3
The air is compressed in the compressor
Implementation Method 4
the intermediate pressure rotor drives a low pressure compressor rotor
Implementation Method 5
The air is compressed in the compressor
Data Source
AI summary
A gas turbine engine comprises a high pressure turbine rotor, an intermediate pressure turbine rotor and a fan drive turbine rotor. The fan drive turbine rotor drives a fan rotor through a gear reduction. The intermediate pressure rotor drives a low pressure compressor rotor and the high pressure turbine rotor drives a high pressure compressor rotor. A first flow cross-sectional area is between an outer periphery of a hub in the low pressure compressor rotor, and an outer tip of an upstream most blade row of the low pressure compressor rotor. A second flow cross-sectional area is between an outer periphery of a hub in the high pressure compressor rotor, and an outer tip of an upstream most blade row of the high pressure compressor rotor. A ratio of the first and second flow cross-sectional areas is greater than or equal to about 0.12 and less than or equal to about 0.33.