Open Rotor Geartrain Layout for Symmetric Rotation Patterns
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Solution Overview
Problem
Existing aircraft propulsion systems with open propulsor rotors lack efficient and cost-effective configurations that allow for symmetric rotating patterns without duplicating research and development efforts or spare parts for different engine cores.
Innovation Solution
The use of a geartrain system comprising a star gear system and a planetary gear system to couple the rotating structure and open propulsor rotor, allowing for counter-rotating or co-rotating configurations in aircraft propulsion systems, which facilitates symmetric rotating patterns and reduces the need for duplicate engine cores and spare parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If duplicate engine cores are used to achieve symmetric rotating patterns, then performance and noise reduction are improved, but manufacturing cost and complexity increase
Solution Approach 1:
A single engine core is designed to perform multiple functions by incorporating a geartrain system that can generate both counter-rotating and co-rotating patterns. The engine core with its geartrain (including star gear system and planetary gear system) can operate in different modes to achieve symmetric rotating patterns, eliminating the need for duplicate engine cores and reducing manufacturing complexity while maintaining performance and noise reduction benefits
2Adaptability or versatility
If a geartrain system is added to enable counter-rotating patterns, then symmetric rotating patterns are achieved, but device complexity increases
Solution Approach 1:
The geartrain system employs a nested configuration where a star gear system is integrated within a planetary gear system. The star gear system's ring gear serves as the sun gear for the planetary gear system, creating a compact nested structure. This nesting approach enables complex counter-rotating and co-rotating functions while minimizing the overall space occupied and reducing the number of separate components needed, thereby managing device complexity more effectively
3Reliability
If spare parts for different engine cores are maintained, then reliability is improved, but inventory cost and complexity increase
Solution Approach 1:
By designing a universal engine core with an integrated geartrain system that can produce both counter-rotating and co-rotating patterns, the need for multiple types of spare parts for different engine core configurations is eliminated. A single engine core design with versatile geartrain capabilities means that one type of spare part can serve multiple operational modes, significantly reducing spare parts inventory requirements while maintaining reliability across different operating conditions
Data Source
AI summary
An assembly is provided for an aircraft. This assembly includes an open propulsor rotor, an engine core and a geartrain. The open propulsor rotor is configured to rotate about an axis. The engine core includes a flowpath, a compressor section, a combustor section, a turbine section and a rotating structure. The flowpath extends through the compressor section, the combustor section and the turbine section from an inlet into the flowpath to an exhaust from the flowpath. The rotating structure includes a compressor rotor in the compressor section and a turbine rotor in the turbine section. The rotating structure is configured to rotate about the axis and drive rotation of the open propulsor rotor. The geartrain is disposed axially between and operatively couples the rotating structure and the open propulsor rotor. The geartrain includes a star gear system and a planetary gear system.