Multi-Spool Gas Turbine Layout for Compact High-Pressure Compression
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Solution Overview
Problem
Conventional gas turbine engines face challenges in achieving improved thermodynamic cycle performance while maintaining a compact and lightweight design, particularly in efficiently arranging components like the accessory gearbox and gear systems to minimize engine envelope and optimize thermodynamic efficiency.
Innovation Solution
The reverse-flow gas turbine engine design features a split compressor system with independently rotatable LP and HP spools, a gear-driven LP compressor, and an axially mounted accessory gearbox, allowing for bidirectional drive and compact configuration through central gear train arrangements that enable efficient energy transfer and reduced engine size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional single-spool gas turbine engine configuration is used, then the engine structure is simple, but the thermodynamic cycle performance is limited and the engine envelope is larger
Solution Approach 1:
The engine is divided into two independent spools (low-pressure spool and high-pressure spool), each with its own compressor and turbine. This segmentation allows independent optimization of compression and expansion processes, improving thermodynamic efficiency while maintaining manageable structural complexity through modular design
Solution Approach 2:
The patent introduces a reverse-flow configuration where the gas path reverses direction between compressor and turbine sections. This dimensional reorganization of the flow path enables more efficient thermodynamic cycling and compact packaging, achieving higher performance density without proportionally increasing structural complexity
2Productivity
If the engine components are arranged to optimize thermodynamic performance, then the thermodynamic cycle performance improves, but the engine envelope size increases
Solution Approach 1:
The low-pressure compressor is positioned within the annular space of the high-pressure compressor, and the low-pressure turbine is positioned within the annular space of the high-pressure turbine. This nested arrangement allows both spools to occupy the same radial space, significantly reducing the engine envelope volume while maintaining the thermodynamic benefits of dual-spool architecture
Solution Approach 2:
The reverse-flow configuration reorganizes the gas path to flow in opposite directions through nested compressor and turbine sections. This enables efficient heat and work transfer in a compact axial arrangement, achieving high thermodynamic performance density without increasing the engine's external dimensions
3Power
If a gear-driven compressor system is implemented, then the power density and pressure ratio improve, but the device complexity increases
Solution Approach 1:
The accessory gearbox is integrated into the center of the low-pressure compressor, combining multiple functions (driving the LP compressor, HP compressor, and other accessories) into a single centralized unit. This merging approach delivers the power density benefits of gear-driven compression while minimizing the added complexity through functional integration
Solution Approach 2:
The low-pressure compressor serves multiple functions: it is driven by the LP turbine through gears to provide compression, its central structure houses the accessory gearbox to drive other engine accessories, and it provides structural support for the entire engine assembly. This multi-functionality achieves high power density without proportionally increasing complexity
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 enhances thermodynamic cycle performance, achieves higher pressure ratios, better specific fuel consumption, and lower turbine inlet temperature, resulting in a more compact, lightweight, and efficient engine with improved power density.
Implementation Method 1
a LP turbine drivingly connected to the output shaft, the LP turbine extracting energy from the combustion gases
Implementation Method 2
a HP turbine drivingly connected to the HP compressor, the HP turbine extracting energy from the combustion gases
Implementation Method 3
a LP compressor pressurizing air from the air inlet
Implementation Method 4
a HP compressor pressurizing air from the LP compressor
Implementation Method 5
a combustor in which the compressed air is mixed with fuel and ignited for generating an annular stream of hot combustion gases
Data Source
Figure 1
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AI summary
A multi-spool gas turbine engine (10) comprises a low pressure (LP) spool (20) and a high pressure (HP) spool (40). The LP spool (20) and the HP spool (40) are independently rotatable about an axis (17). The LP pressure spool (20) has an LP compressor (22) and an LP turbine (21). The HP spool (40) has an HP turbine (41) and an HP compressor (42). An accessory gear box (AGB) (50) is axially mounted at one end of the engine (10). The LP compressor (22) is axially positioned between the HP compressor (42) and the AGB (50). The AGB (50) is drivingly connected to the HP spool (40) through the center of the LP compressor (22).