Gas Turbine Multi-Fan Gear Transmission
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Solution Overview
Problem
Large fan diameters in gas turbine engines pose challenges in efficient power transmission to multiple fan rotors, as existing proposals for driving multiple fan rotors from a single core engine do not effectively share power among them.
Innovation Solution
A gas turbine engine design featuring a core engine with a compressor, combustor, and turbine that drives at least four gears through an output shaft, with a pair of bevel gears rotating together to drive each of the four fan rotors efficiently, allowing for separate exhaust management of the core engine and fan rotors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single core engine drives multiple fan rotors, then the bypass ratio is improved and power distribution is enhanced, but the transmission system complexity increases
Solution Approach 1:
The transmission system is segmented into multiple independent gear trains, each driving a separate fan rotor. The core engine's output shaft connects to multiple gear sets that can be independently configured, allowing each fan rotor to receive power through its own transmission path. This segmentation enables efficient power distribution to multiple fans while maintaining manageable complexity in each individual gear train.
Solution Approach 2:
The core engine's output shaft serves multiple functions by simultaneously driving multiple fan rotors through a shared transmission interface. The gear reduction system is designed to universally accommodate multiple output paths, where a single core engine can power any number of fan rotors depending on the configuration, making the transmission system adaptable and multi-functional.
2Productivity
If fan diameter is increased, then the bypass ratio is improved, but the packaging and operation challenges increase
Solution Approach 1:
Instead of using a single large fan rotor that creates packaging difficulties, the system segments the fan function into multiple smaller rotors. These smaller rotors can be more compactly arranged within the engine nacelle, improving packaging while collectively providing the same or greater bypass airflow capability as a single large fan.
Solution Approach 2:
The system transitions from a single-dimensional large fan configuration to a multi-dimensional arrangement of multiple smaller fans. By distributing the fan function across multiple rotors positioned at different locations and orientations, the design achieves the required bypass ratio without the packaging constraints of a single oversized fan.
3Adaptability or versatility
If existing proposals drive four fan rotors from a single core engine, then the power distribution capability is improved, but the power sharing efficiency deteriorates
Solution Approach 1:
Each fan rotor is equipped with its own dedicated gear reduction system optimized for its specific power requirements. Rather than using a uniform transmission approach for all fans, the system allows each local transmission path to be tailored to the specific needs of each fan rotor, improving overall power sharing efficiency by matching transmission characteristics to local demands.
Solution Approach 2:
The transmission system is designed with dynamic power distribution capabilities, allowing the core engine to flexibly allocate power to different fan rotors based on operational conditions. The gear trains can be configured to provide variable speed ratios and power levels to each fan, enabling efficient power sharing that adapts to changing flight conditions and fan performance requirements.
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
Enables efficient power sharing and operation of multiple fan rotors, improving the bypass ratio and maintaining separate exhaust systems for the core engine and fan rotors, enhancing the overall efficiency and packaging of the engine.
Implementation Method 1
a turbine. The turbine drives an output shaft
Implementation Method 2
The output shaft drives at least four gears, each of the at least four gears extending through a drive shaft to drive an associated fan rotor
Implementation Method 3
the output of the core engine drives a pair of bevel gears. Each of the at least four gears are driven by at least one of the pair of bevel gears
Data Source
AI summary
A gas turbine engine includes a core engine with a compressor section, a combustor and a turbine. The turbine drives an output shaft, and the output shaft drives at least four gears. Each of the at least four gears extends through a drive shaft to drive an associated fan rotor.