Accessory Gearbox Layout for Compact Geared Gas Turbine Engines
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Solution Overview
Problem
Conventional accessory gearboxes in gas turbine engines, especially those with geared fan-drive architectures, face challenges in packaging and mounting due to limited axial length and exposure to high temperatures, making it difficult to efficiently integrate and cool these components within the engine.
Innovation Solution
The accessory gearbox is strategically positioned within a core compartment of the gas turbine engine, mounted directly to the engine's casing, and divided into separate portions to optimize space and thermal management, allowing for efficient integration and maintenance while minimizing axial length and exposure to high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the accessory gearbox is located near the aft of the engine, then it can be mounted to the fan case, but it requires a relatively long driveshaft from the compressor and exposes the gearbox to relatively high temperatures
Solution Approach 1:
The accessory gearbox is repositioned from the conventional aft location to a forward position within the core compartment, utilizing the radial space between the compressor and turbine sections. This dimensional repositioning reduces thermal exposure while maintaining mounting feasibility through direct attachment to the compressor casing.
Solution Approach 2:
The accessory gearbox is extracted from the conventional aft mounting location and repositioned to the forward core compartment. This extraction allows the gearbox to be mounted directly to the compressor casing, eliminating the need for a long driveshaft and reducing thermal exposure from exhaust gases.
2Length of moving object
If the accessory gearbox is packaged within a shorter axial length engine, then the overall engine length is reduced, but packaging the gearbox and accessories becomes more difficult
Solution Approach 1:
The accessory gearbox is repositioned radially within the core compartment, utilizing the space between the compressor and turbine sections rather than extending axially. This radial arrangement allows compact packaging within a shorter axial length engine while maintaining accessibility for maintenance.
Solution Approach 2:
The accessory gearbox is nested within the core compartment, utilizing the existing engine structure and space between rotating components. This nesting approach allows the gearbox to be integrated into the engine's internal volume without increasing overall axial length.
3Temperature
If the accessory gearbox is divided into separate portions, then space optimization and thermal management are improved, but the device complexity increases
Solution Approach 1:
The accessory gearbox is divided into a first portion and a second portion, with each portion mounted to different sections of the compressor casing. This segmentation allows each portion to be independently cooled by compressor air, improving thermal management while maintaining a relatively simple overall structure.
Data Source
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AI summary
A gas turbine engine includes a gearbox. The gearbox includes a housing at a forward part of a core compartment of a gas turbine engine. A plurality of accessory drives are each configured to rotatably couple the gas turbine engine accessory gearbox to one of a plurality of accessory components.