Geared Turbofan Efficiency Rating for Gear Ratio Architecture
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Solution Overview
Problem
Geared turbofan engines face increased complexity during development and manufacturing due to the inclusion of a gearbox, necessitating improved methods and devices for more efficient and precise development and manufacturing.
Innovation Solution
The introduction of an overall engine efficiency rating formula, Q (D1.56T)1.5N2, which incorporates gearbox oil flow rate (Q), fan blade diameter (D), and low-pressure turbine stages (N) to optimize engine architecture and simplify development, with specific gear ratios ranging from 2.0 to 4.0 and efficiency ratings between 0.57 and 8.0, facilitating improved turbomachine engines.
Engineering Contradictions & Design Principles
Engineering 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 is improved, but device complexity increases making development and manufacturing more difficult
Solution Approach 1:
The patent introduces an overall engine efficiency rating parameter that combines multiple engine parameters (gearbox oil flow rate, fan blade diameter, net thrust, number of rotating blade stages) into a single metric. This parameter change enables systematic optimization of geared turbofan engines by providing a quantitative basis for evaluating and comparing different engine configurations, thereby resolving the contradiction between achieving maximum efficiency through gearboxes and managing the increased complexity they introduce.
2Power
If a gearbox is included in a turbofan engine to enable optimized rotational speeds, then power production efficiency is improved, but manufacturing difficulty increases
Solution Approach 1:
The patent establishes the overall engine efficiency rating as a preliminary design tool that allows engineers to optimize engine architecture and select appropriate gear ratios (2.0-4.0) before detailed manufacturing begins. By using this rating to pre-determine optimal configurations of the gearbox, fan, and low-pressure turbine, the patent reduces manufacturing complexity by eliminating the need for extensive trial-and-error prototyping and testing of different gearbox configurations.
3Productivity
If an overall engine efficiency rating is introduced to optimize engine architecture, then development efficiency is improved, but measurement and calculation complexity increases
Solution Approach 1:
The overall engine efficiency rating serves multiple functions simultaneously: it evaluates engine performance, guides optimization of major components (gearbox, fan, low-pressure turbine), and provides a basis for comparing different engine architectures. This multi-functionality improves development efficiency by consolidating what would otherwise require multiple separate evaluation metrics into a single comprehensive parameter, thereby reducing the overall complexity of the development process despite the sophisticated calculation required.
Data Source
AI summary
A turbomachine engine can include a fan assembly, a vane assembly, a core engine, a gearbox, and an overall engine 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 a low-pressure turbine. The gearbox includes an input and an output. The input of the gearbox is coupled to the low-pressure turbine of the core engine and comprises a first rotational speed, the output of the gearbox 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 2.0-4.0.