Integral Drive Engine Gearbox Forward Mounting
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Solution Overview
Problem
The existing gas turbine engine architecture is lengthened and weighted by a frame between the low pressure compressor and the fan assembly to support the gearbox, leading to increased cost and non-optimal operation due to high loading on the low pressure compressor.
Innovation Solution
The low pressure compressor is directly coupled to the fan assembly, and the gearbox is positioned axially forward of the fan assembly, eliminating the need for an additional frame and allowing for a common spool configuration that synchronizes or adjusts the speed of the fan and compressor with the low pressure turbine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a frame is added between the low pressure compressor and fan assembly to support the gearbox, then the gearbox can be properly positioned and supported, but the engine length, weight, and cost increase
Solution Approach 1:
The patent merges the gearbox support function into the existing fan assembly structure. The gearbox is mounted directly to the fan assembly, eliminating the need for a separate frame structure. This integration achieves both gearbox support and reduces overall engine weight by removing redundant structural components.
2Device complexity
If the low pressure compressor rotates at high speed to match low pressure turbine speed, then the turbine-compressor coupling is simplified, but the low pressure compressor operates at non-optimal pressure ratio with high loading
Solution Approach 1:
The patent introduces a gearbox as an intermediary mechanism between the low pressure turbine and low pressure compressor. The gearbox enables speed conversion, allowing the low pressure compressor to rotate at a lower, optimized speed for better pressure ratio while the low pressure turbine operates at its optimal high speed. This mediator resolves the conflict between coupling simplicity and compressor performance.
3Device complexity
If the gearbox is positioned between the low pressure compressor and fan assembly, then the drive train is compact, but maintenance access to the gearbox is difficult
Solution Approach 1:
The patent inverts the conventional gearbox positioning by placing it forward of the fan assembly rather than between the compressor and fan. This reversal of the expected arrangement improves maintenance access, as the gearbox becomes more accessible from the front of the engine while still maintaining a compact drive train configuration through the forward mounting location.
Data Source
AI summary
The gas turbine engine includes a core engine, a low pressure turbine, a fan assembly, a gearbox, and a lubrication scavenge pump. The core engine includes a high pressure compressor, a combustor, and a high pressure turbine configured in a serial flow arrangement. The low pressure turbine is positioned axially aft of the core engine. The fan assembly is positioned axially forward of the core engine. The gearbox is positioned axially forward of the fan assembly. The lubrication scavenge pump is positioned forward of the gearbox.