Geared Turbofan Gearbox Efficiency Rating for Engine Development

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Solution Overview

Problem

Geared turbofan engines face increased complexity due to the inclusion of a gearbox, making engine development and manufacturing more difficult, necessitating improved methods for efficiency and precision in their development and manufacturing.

Innovation Solution

The introduction of a gearbox efficiency rating (GER) formula, Q(D1.5⁢6T)1.5⁢3, which aids in the development of turbomachine engines by quantifying gearbox efficiency based on oil flow rate, fan diameter, and net thrust, simplifying the development process and improving engine performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a gearbox is included in a turbofan engine to allow power turbine and bypass fan to operate at different rotational speeds for maximum efficiency, then engine efficiency and power production are improved, but device complexity and manufacturing difficulty increase significantly

Engineering Contradiction:

Improveengine efficiencyVSAvoidengine complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent introduces a gearbox efficiency rating parameter that quantifies the relationship between gearbox oil flow rate, fan diameter, and net thrust. This parameter change enables systematic optimization of gearbox performance while managing the complexity introduced by the gearbox component.

Inventive Principle:

Principle #35Parameter changes

2Power

If a gearbox is included in a turbofan engine to allow power turbine and bypass fan to operate at different rotational speeds, then power production is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvepower productionVSAvoidmanufacturing precision

Core Design Contradiction:

PowerVSManufacturing precision

Solution Approach 1:

The gearbox efficiency rating serves as a feedback mechanism that relates oil flow rate, fan diameter, and net thrust. This feedback loop enables manufacturers to adjust and optimize gearbox design parameters to achieve desired power production while controlling manufacturing precision requirements.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If a gearbox is included in a turbofan engine, then operational flexibility is improved, but development time and complexity increase

Engineering Contradiction:

Improveoperational flexibilityVSAvoiddevelopment time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent establishes the gearbox efficiency rating as a predetermined parameter that can be used during the design phase to predict and optimize gearbox performance. This preliminary characterization reduces development time by enabling early assessment of gearbox suitability for different operational requirements.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11802516B2Gearbox efficiency rating for turbomachine engines

Publication Date: 2023.10.31 GE AVIO SRL

AI summary

A turbomachine engine can include a fan assembly, a vane assembly, a core engine, a gearbox, and a gearbox efficiency rating. The fan assembly can include a plurality of fan blades. The vane assembly can include a plurality of vanes, and the vanes can, in some instances, be disposed aft of the fan blades. The core engine can include one or more compressor sections and one or more turbine sections. The gearbox includes an input and an output. The input is coupled to the one or more turbine sections of the core engine and comprises a first rotational speed, the output is coupled to the fan assembly and has a second rotational speed, and a gear ratio of the first rotational speed to the second rotational speed is within a range of 4.1-14.0. The gearbox efficiency rating is 0.10-1.8.