Geared Gas Turbine Engine High Power Extraction
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Solution Overview
Problem
Current geared gas turbine engines for aircraft have a relatively low power output, specifically requiring a high power output of greater than 38,000 horsepower at maximum take-off conditions, which is not efficiently achieved with the existing low pressure ratio turbine design.
Innovation Solution
The design incorporates a gas turbine engine with a gearbox that drives a fan at a lower rotational speed than the core shaft, featuring a turbine with a specific area ratio and axial length, multiple stages of turbine rotor and stator blades, and intermetallic materials, optimized for higher power extraction and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a low pressure ratio turbine design is used in a geared gas turbine engine, then the device complexity is reduced, but the power output is insufficient (less than 38,000 horsepower required)
Solution Approach 1:
The patent applies parameter changes by optimizing the turbine outlet to inlet area ratio to a specific range (2.5-3.5) and controlling the axial Mach number distribution (0.15-0.35 at inlet, 0.45-0.60 at outlet). These parameter optimizations enable the low pressure ratio turbine to achieve the required 38,000+ horsepower power output while maintaining manageable design complexity through systematic parameter control.
2Power
If the turbine outlet area is increased to improve power extraction, then the power output increases, but the axial length and volume of the turbine increase
Solution Approach 1:
The patent resolves this contradiction by optimizing the outlet to inlet area ratio to a specific range (2.5-3.5) rather than simply increasing the outlet area indefinitely. This controlled parameter change, combined with Mach number management, enables effective power extraction while limiting the axial length increase to a manageable extent (at least 230 mm but less than 580 mm).
Solution Approach 2:
The patent manages the volume and length trade-off by controlling the radial expansion (area ratio) rather than solely increasing axial length. By optimizing the area ratio in the radial dimension and managing axial Mach numbers, the design achieves high power extraction with controlled axial length, effectively using dimensional optimization to resolve the contradiction.
3Power
If multiple stages of turbine rotor blades are added to increase power output, then the power extraction improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies parameter changes by specifying optimal Mach number ranges for each blade stage (inlet 0.15-0.35, outlet 0.45-0.60) and optimizing the area ratio (2.5-3.5). These parameter optimizations enable effective power extraction through the multi-stage blade arrangement while managing manufacturing complexity through systematic design guidelines.
Solution Approach 2:
The patent divides the turbine into multiple axial stages of rotor blades, with each stage contributing to progressive power extraction. This segmentation allows the total power requirement to be distributed across several smaller, more manageable blade stages, each operating within optimized Mach number ranges, thereby reducing the manufacturing difficulty compared to a single complex stage.
4Power
If the axial Mach number at the turbine inlet is increased to improve power extraction, then the power output increases, but the aerodynamic losses and efficiency decrease
Solution Approach 1:
The patent optimizes the inlet axial Mach number to a specific range (0.15-0.35) rather than simply increasing it indefinitely. This controlled parameter change, combined with optimizing the outlet Mach number (0.45-0.60) and the area ratio (2.5-3.5), enables effective power extraction while minimizing aerodynamic losses and maintaining efficiency through systematic parameter optimization.
Data Source
AI summary
A gas turbine engine for an aircraft includes an engine core with a turbine, a compressor, and a core shaft connecting them. The engine includes a fan, with a plurality of fan blades, located upstream of the core and a gearbox receiving an input from the core shaft and outputting drive so the fan is at a lower rotational speed than the core shaft. The turbine includes a plurality of stages of axially spaced rotor blades mounted on a rotor, which are surrounded by a turbine casing. The turbine has an inlet defined at an upstream end of a first stage of blades and an outlet defined at a downstream end of a last stage of blades and a ratio of the area of the outlet to the inlet is at between 2.5 and 3.5. This increases the pressure ratio of and power extracted from the turbine and the engine.