Turbomachine Gearbox Efficiency Rating for Oil Flow Sizing
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Solution Overview
Problem
Geared turbofan engines face complexity and inefficiencies in development and manufacturing due to the introduction of a gearbox, necessitating improved methods for design and production.
Innovation Solution
The introduction of a gearbox efficiency rating (GER) formula, Q(D1.56T)1.53, which calculates oil flow rate based on gearbox oil flow, fan diameter, and net thrust, aids in simplifying gearbox development and optimizing engine performance by providing a standardized metric for gearbox sizing and oil flow requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a gearbox is introduced 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
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-based approach allows engineers to optimize gearbox design and operation by adjusting specific parameters (oil flow rate, gear ratio) rather than redesigning the entire gearbox system, thus improving efficiency while managing complexity.
2Power
If a gearbox is introduced in a turbofan engine to allow power turbine and bypass fan to operate at different rotational speeds, then power production is improved, but manufacturing difficulty increases significantly
Solution Approach 1:
The patent establishes the gearbox efficiency rating as a predetermined design parameter that guides gearbox selection and configuration before manufacturing begins. By calculating and specifying the required oil flow rate and gear ratio in advance based on engine performance requirements, the manufacturing process is simplified and standardized, reducing complexity while enabling higher power production.
3Loss of energy
If gearbox oil flow rate is increased to improve gearbox efficiency, then power transmission efficiency is improved, but loss of substance (oil consumption) increases
Solution Approach 1:
The patent defines a specific mathematical relationship (gearbox efficiency rating = Q×D^1.5×6/T^1.5×3) that allows optimization of oil flow rate Q to achieve maximum power transmission efficiency while minimizing excessive oil consumption. The parameter-based approach enables precise control of oil flow rates rather than using excessive amounts, balancing efficiency improvement with substance conservation.
Data Source
AI summary
A turbomachine engine can include a fan assembly, a pitch change mechanism, a vane assembly, a core engine, a gearbox, and a gearbox efficiency rating. The fan assembly can include a plurality of fan blades. The pitch change mechanism can be coupled to the fan assembly. The vane assembly can include a plurality of vanes. 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.