Three-Stream Turbofan With Embedded Electric Machine Coupling
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Solution Overview
Problem
Existing gas turbine engines face challenges in optimizing engine performance and operability with increasing power generation and transmission capabilities of electric machines, necessitating improved architectural arrangements and operating relationships.
Innovation Solution
A three-stream gas turbine engine with an embedded electric machine is designed to produce three distinct streams of propulsive thrust, featuring a primary fan, mid-fan, and core engine components arranged to achieve specific tip speed, radius, and power ratios, with the electric machine coupled to the low-pressure shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If electric machines increase power generation and transmission capability, then electrical power output is improved, but device complexity increases
Solution Approach 1:
The patent combines the electric machine with the gas turbine engine by mechanically coupling the electric machine rotor to the engine's low-pressure shaft. This integration allows the electric machine to generate electrical power while sharing mechanical infrastructure with the engine, thereby increasing power output without proportionally increasing overall device complexity
Solution Approach 2:
The low-pressure shaft serves dual functions: it drives both the electric machine rotor for electrical power generation and the engine's propulsion system. This multi-functionality allows the same mechanical component to support both electrical power generation and engine operation, reducing the need for separate dedicated components
2Productivity
If three-stream configuration is implemented, then engine efficiency is improved, but device complexity increases
Solution Approach 1:
The engine is divided into three distinct airflow streams: a core stream through the compressor and combustion chamber, a fan stream from the primary fan, and a mid-fan stream from the secondary fan. Each stream is processed through dedicated pathways and exits through separate nozzles, allowing independent optimization of each stream's contribution to overall engine efficiency while maintaining clear functional separation
Solution Approach 2:
The patent introduces a mid-fan stage between the primary fan and the core engine, adding a dimensional layer to the traditional two-stream turbofan configuration. This intermediate stage creates an additional thrust stream that operates in a different spatial and functional dimension, enabling improved efficiency without completely redesigning the fundamental engine architecture
3Productivity
If hybrid-electric propulsion system is integrated, then overall performance is improved, but ease of operation deteriorates
Solution Approach 1:
The control system continuously monitors engine parameters including shaft speed, electrical power generation, and thrust output, using this feedback to dynamically adjust the operation of the electric machine and engine components. This closed-loop control automatically optimizes the hybrid-electric system's performance across varying flight conditions, reducing the operational burden on pilots while maintaining improved overall performance
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, reduces fuel burn, and provides improved overall performance and operability compared to conventional turbofan engines, while allowing for hybrid-electric propulsion systems.
Implementation Method 1
an electric machine mechanically coupled thereto
Implementation Method 2
The flow of combustion gasses through the turbine section drives the turbine section
Implementation Method 3
one or more axial compressors progressively compress the air
Data Source
AI summary
A three-stream gas turbine engine with an embedded electric machine and methods of operating the same are disclosed. In one aspect, a three-stream engine includes an electric machine operatively coupled with a shaft of the engine. The three-stream engine also includes a core engine and a primary fan and a mid-fan positioned upstream of the core engine. The primary fan and the mid-fan are operatively coupled with the shaft. During operation, the three-stream engine defines a tip speed ratio being defined by a tip speed of a rotor of the electric machine to a tip speed of a mid-fan blade of the mid-fan. The tip speed ratio is defined as being equal to or greater than 0.2 and less than or equal to 1.0.