Gas Turbine Spool Power Sharing via Coupled Geartrains
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Solution Overview
Problem
Existing gas turbine engines lack an efficient mechanical power sharing mechanism between the high and low pressure spools, necessitating hybrid-electric propulsion systems for power transfer, which are not optimal for various operating conditions.
Innovation Solution
A mechanical power sharing arrangement is implemented using a low pressure geartrain coupled to a low pressure spool and a high pressure geartrain coupled to a high pressure spool, with a common axial location and shared oil sump, allowing power transfer via a continuous variable transmission, hydraulic, or pneumatic system, and including clutches for selective decoupling based on operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If hybrid-electric propulsion systems are used to transfer power between spools, then power transfer capability is achieved, but system complexity and weight increase
Solution Approach 1:
The patent replaces hybrid-electric propulsion systems with a direct mechanical power sharing arrangement using geartrains and a power transfer device. The low pressure geartrain and high pressure geartrain are mechanically coupled through a power transfer device, eliminating the need for electric machines and associated electrical systems while maintaining power transfer capability between spools.
Solution Approach 2:
The patent merges the low pressure geartrain and high pressure geartrain into a single integrated mechanical system with a common oil sump and shared structural support. This consolidation reduces the number of separate systems while maintaining the ability to transfer power between spools through the combined geartrain assembly.
2Reliability
If separate sumps are used for each geartrain, then lubrication is provided, but device complexity and space requirements increase
Solution Approach 1:
The patent combines the lubrication systems for the low pressure geartrain and high pressure geartrain into a single common oil sump. This unified sump serves both geartrains simultaneously, reducing the number of separate lubrication systems while ensuring reliable lubrication for all mechanical components through a shared oil supply.
3Device complexity
If fixed gear ratio connections are used between spools, then structural simplicity is maintained, but adaptability to various operating conditions is reduced
Solution Approach 1:
The patent incorporates a power transfer device that can dynamically adjust the mechanical connection between the low pressure and high pressure geartrains. This device allows the gear ratio and power flow to vary based on operating conditions, enabling the system to adapt to different flight regimes while maintaining a relatively simple overall structure through the use of a continuous variable transmission or adjustable gear mechanism.
Data Source
AI summary
A gas turbine engine includes a low pressure spool that connects a low pressure compressor to a low pressure turbine. The gas turbine engine further includes a high pressure spool that connects a high pressure compressor to a high pressure turbine. The gas turbine engine further includes a high pressure geartrain coupled in gear with the high pressure spool. The gas turbine engine further includes a low pressure geartrain coupled in gear with the low pressure spool. The gas turbine engine further includes a power transfer device coupling the high pressure geartrain and the low pressure geartrain to transfer power between the high pressure spool and the low pressure spool.