Reverse Flow Gas Turbine Core Architecture

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Solution Overview

Problem

Existing reverse core gas turbine engines face limitations in efficiency and design constraints, particularly due to the nesting of low and high pressure shafts which affects performance and serviceability, especially in turboshaft engines like those powering helicopters.

Innovation Solution

The design incorporates a reverse flow configuration with a mechanically decoupled core section, featuring a low pressure compressor and turbine, a high pressure compressor and turbine, and a power turbine, with fluid flow reversed by duct systems to optimize pressure ratios and accessibility, allowing for higher efficiency and easier maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a reverse core engine configuration is used, then engine operating efficiency is improved, but design complexity and shaft nesting constraints increase

Engineering Contradiction:

Improveengine operating efficiencyVSAvoidshaft nesting constraints

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The engine is divided into separate functional modules: a core section containing the high-pressure compressor and turbine, and a power section containing the low-pressure compressor and power turbine. The core section is mechanically decoupled from the power section, allowing independent operation and removal of the core for maintenance without affecting the power section.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The core section is extracted and mechanically decoupled from the power section. This allows the core to be removed and serviced independently, eliminating the shaft nesting constraints that would otherwise prevent easy access to high-temperature components.

Inventive Principle:

Principle #2Taking out (Extraction)

2Ease of repair

If the core section is mechanically decoupled, then serviceability is improved, but device complexity increases

Engineering Contradiction:

ImproveserviceabilityVSAvoidmechanical decoupling

Core Design Contradiction:

Ease of repairVSDevice complexity

Solution Approach 1:

The engine is segmented into a core section and a power section that are mechanically decoupled. The core section can be independently removed and serviced, improving access to high-temperature components without requiring disassembly of the entire engine.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A fluid coupling device is introduced as an intermediary between the core section and power section. This allows mechanical decoupling while maintaining fluid communication, enabling independent servicing of the core section without affecting the power section.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Power

If fluid flow is reversed through duct systems, then pressure ratios are optimized, but device complexity increases

Engineering Contradiction:

Improvepressure ratiosVSAvoidduct systems

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The fluid flow direction is inverted in the core section. The high-pressure compressor discharges fluid to the rear, and the high-pressure turbine receives fluid from the rear and discharges it forward. This reverse flow configuration optimizes pressure ratios and allows for more efficient engine operation.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The duct systems are arranged in a nested configuration where the first duct system is positioned within or alongside the second duct system. This compact arrangement minimizes the overall engine size and reduces the complexity of the duct work while still achieving the required flow reversal and pressure optimization.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 engine efficiency by eliminating design limitations on shafts, achieving higher overall pressure ratios and facilitating easier servicing of the core section, which is subjected to the highest temperatures and wear.

Implementation Method 1

The first duct system is arranged to reverse fluid flow before entry into the core section

Methodology Applied

Scientific EffectFluid flow reversal:

Implementation Method 2

a centrifugal compressor arranged fluidly between the second compressor and the combustor

Methodology Applied

Scientific EffectCentrifugal compression: Centrifugal Force

Implementation Method 3

The hot combustion gases are communicated through the turbine section, which extracts energy from the hot combustion gases to power the compressor section and other gas turbine engine loads

Methodology Applied

Scientific EffectTurbine energy extraction: Turbine

Implementation Method 4

fluid is pressurized in the compressor section and mixed with fuel and burned in the combustor section to generate hot combustion gases

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS10794273B2Advanced distributed engine architecture-design alternative

Publication Date: 2020.10.06 RTX CORP

AI summary

A gas turbine engine according to the present disclosure includes a first compressor and a first turbine for driving the first compressor. A core section includes a second compressor and a second turbine for driving the second compressor. A third turbine is arranged fluidly downstream of the first turbine and the second turbine and configured to drive a power take-off. A first duct system is arranged fluidly between the low-pressure compressor and the core section. The first duct system is arranged to reverse fluid flow before entry into the core section.