Epicyclic Geared Turbine Architecture for Compressor Speed Decoupling

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Solution Overview

Problem

Turbine engine manufacturers seek further improvements in thermal, transfer, and propulsive efficiencies in geared architectures of gas turbine engines.

Innovation Solution

The implementation of geared architectures that allow the compressor section to rotate at faster or different rotational speeds than the turbine section, utilizing epicyclical gear systems to adjust rotational speeds and optimize engine performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the fan section rotates at a slower speed than the turbine section (using traditional geared architecture), then propulsive efficiency is improved, but the engine size and weight increase

Engineering Contradiction:

Improvepropulsive efficiencyVSAvoidengine weight

Core Design Contradiction:

Use of energy by moving objectVSWeight of stationary object

Solution Approach 1:

The patent applies nesting by placing the epicyclical gear assembly within the existing engine structure, specifically utilizing the space between the high pressure compressor and low pressure turbine. The gear assembly is integrated into the engine core rather than being added as a separate external component, allowing the speed reduction mechanism to be contained within the existing engine envelope. This nested arrangement reduces the overall engine size and weight while maintaining the speed reduction function needed for improved propulsive efficiency.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Power

If the compressor section rotates at a faster rotational speed than the turbine section, then power transfer efficiency is improved, but mechanical stress and reliability concerns increase

Engineering Contradiction:

Improvepower transfer efficiencyVSAvoidmechanical stress

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent applies dynamics by implementing variable geometry stators in the turbine section that can adjust their blade angles in response to changing operating conditions. This dynamic adjustment allows the turbine to maintain optimal efficiency across a wider range of compressor speeds, reducing peak mechanical stresses. Additionally, the epicyclical gear assembly provides continuous variable ratio capability, allowing the system to dynamically optimize the speed ratio between compressor and turbine to minimize stress while maximizing power transfer efficiency.

Inventive Principle:

Principle #15Dynamics

3Device complexity

If an epicyclical gear assembly is used to reduce fan speed, then part count is reduced and compactness is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvepart countVSAvoidmanufacturing complexity

Core Design Contradiction:

Device complexityVSEase of manufacture

Solution Approach 1:

The patent applies universality by designing the epicyclical gear assembly to serve multiple functions simultaneously: it provides speed reduction for the fan, supports the low pressure turbine, and integrates with the engine mounting structure. The gear assembly is designed as a unified component set that performs several mechanical functions that would otherwise require separate components, thereby reducing the overall part count while managing manufacturing complexity through functional integration.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Use of energy by moving object

If the low pressure turbine drives the low pressure compressor at different speeds, then thermal efficiency is improved, but the mechanical connection complexity increases

Engineering Contradiction:

Improvethermal efficiencyVSAvoidmechanical connection complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent applies merging by combining the speed reduction function with the existing mechanical connection between the low pressure turbine and low pressure compressor. The epicyclical gear assembly is integrated into this existing power transmission path, merging the speed adjustment function with the existing mechanical linkage rather than adding a separate, complex connection system. This integration reduces mechanical connection complexity while enabling the different speed operation needed for improved thermal efficiency.

Inventive Principle:

Principle #5Merging (Combining)

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 compactness, reduces part count, and improves power transfer efficiency while maintaining optimal speeds for both turbine and fan sections.

Implementation Method 1

A low pressure turbine of the turbine section is mechanically connected to a low pressure compressor of the compressor section such that the low pressure turbine rotatably drives the low pressure compressor at a different rotational speed through an epicyclical gear assembly

Methodology Applied

Scientific EffectEpicyclical gearing: Epicyclic Gearing

Data Source

PatentEP3961016B1Gas turbine engine geared architecture

Publication Date: 2026.03.04 RTX CORP

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AI summary

A gas turbine engine assembly according to an exemplary aspect of the present disclosure includes, among other things, a geared architecture configured to rotatably couple a turbine and a compressor of an engine to rotate the compressor at a different speed than the turbine and a fan.