Reverse-Flow Gas Turbine Split Compressor Layout for Higher Efficiency

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Solution Overview

Problem

Conventional reverse-flow gas turbine engines inefficiently utilize a single compressor stage driven by a first turbine stage, affecting overall engine efficiency.

Innovation Solution

A split compressor system is implemented, where a low-pressure turbine drives both a low-pressure compressor and a high-pressure compressor, allowing for bidirectional drive and improved thermodynamic efficiency, with the low-pressure turbine section driving the low-pressure compressor and high-pressure compressor independently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single compressor stage is used, then the device complexity is reduced, but the engine efficiency deteriorates

Engineering Contradiction:
Improvecompressor structureVSAvoidengine efficiency
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The compressor is divided into two independent stages: a first compressor stage driven by the first turbine stage, and a second compressor stage driven by the second turbine stage. This segmentation allows each stage to operate optimally without the constraints of a single-stage design, improving overall compression efficiency while maintaining manageable structural complexity through modular architecture.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a single turbine stage performs all compression work, then the device complexity is reduced, but the engine efficiency deteriorates

Engineering Contradiction:
Improveturbine structureVSAvoidcompression work efficiency
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The turbine system is segmented into two independent turbine stages, each driving a separate compressor stage. The first turbine stage drives the first compressor stage, while the second turbine stage drives the second compressor stage. This segmentation distributes the compression work across two stages, improving thermodynamic efficiency by reducing the work burden on any single turbine stage and allowing for optimized energy extraction from the combustion gases.

Inventive Principle:
Principle #1Segmentation

3Use of energy by moving object

If a split compressor system is implemented, then the engine efficiency is improved, but the device complexity increases

Engineering Contradiction:
Improvecompression work distributionVSAvoidcompressor system
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The compressor system is segmented into two independent stages with separate drive mechanisms. Each stage can be optimized for its specific compression ratio and operating conditions, improving overall efficiency. The modular design allows for independent maintenance and replacement of each stage, mitigating the complexity increase through standardized components and clear functional separation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The split compressor system is integrated with the dual-turbine architecture, where each turbine stage serves both to drive its corresponding compressor stage and to contribute to the overall power output. This multi-functionality justifies the increased complexity by delivering dual benefits: improved compression efficiency and enhanced power generation capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enhances engine efficiency by optimizing compression work distribution, achieving higher pressure ratios, lower specific fuel consumption, and reduced turbine inlet temperature, contributing to lower overall weight and improved power density.

Implementation Method 1

a low-pressure turbine section (21) disposed forward of the low-pressure compressor section (22) and the high-pressure compressor section (42), the low-pressure turbine section (21) drivingly engaged to the low-pressure compressor section (22) and the high-pressure compressor section (42) to drive the low-pressure compressor section (22) and the high-pressure compressor section (42) independently

Methodology Applied
Scientific EffectTurbine: Turbine

Implementation Method 2

a combustor (13) in which the compressed air is mixed with fuel and ignited for generating an annular stream of hot combustion gases

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

a first compressor section (22) disposed aft of the low-pressure turbine section (21), a second compressor section (42) disposed forward of the low-pressure compressor section (22), the low-pressure turbine section (21) drivingly engaged to the low-pressure compressor section (22) and the high-pressure compressor section (42) to drive the low-pressure compressor section (22) and the high-pressure compressor section (42) independently

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3957839B1Reverse-flow gas turbine engine
Publication Date: 2025.12.24 PRATT & WHITNEY CANADA CORP
  • EP3957839B1 patent drawingFigure 1
  • EP3957839B1 patent drawingFigure 2

AI summary

A gas turbine engine (10) has a first spool (20) having a low pressure compressor section (22) disposed forward of an air inlet (11) along a direction of travel of the engine (10), and a low pressure turbine section (21) disposed forward of the low pressure compressor section (22) and drivingly engaged thereto. A second spool (40) has a high pressure compressor section (42) disposed forward of the low pressure compressor section (22), and a high pressure turbine section (41) disposed forward of the high pressure compressor section (42) and drivingly engaged thereto. The high pressure turbine section (41) is disposed aft of the low pressure turbine section (21). An output drive shaft (24) drivingly engages the low pressure turbine section (21) and extends forwardly therefrom to drive a rotatable load (16). A method of operating a gas turbine engine (10) is also discussed.