Angled Drag Links for Bypass Duct Pressure Loss
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Solution Overview
Problem
The thrust specific fuel consumption (TSFC) in gas turbine engines is sensitive to pressure loss in the bypass duct, particularly due to thrust reverser drag links, which contribute to airflow obstruction when deployed during landing.
Innovation Solution
The drag links within the bypass duct are individually configured to align with local airflow angles, determined through computational analysis, to minimize pressure loss while maintaining functionality, by being circumferentially spaced and pivotally attached to the engine core and blocker doors at non-aligned angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drag links are configured to pivot blocker doors into a flow blocking position when thrust reverser is deployed, then thrust reverser functionality is maintained, but pressure loss in the bypass duct increases and TSFC worsens
Solution Approach 1:
Each drag link is individually configured with a specific angle relative to the bypass duct centerline, tailored to its local position and the local airflow angle at that position. This local optimization allows each drag link to minimize pressure loss at its specific location while collectively maintaining thrust reverser functionality across the entire duct.
Solution Approach 2:
The angle parameter of each drag link is varied based on its circumferential position in the bypass duct. By changing the orientation angle of each drag link to match the local airflow angle at its position, the design optimizes airflow alignment and minimizes pressure loss while preserving the flow blocking function when the thrust reverser is deployed.
2Loss of energy
If drag links are individually configured to align with local flow angles, then pressure loss is reduced and TSFC improves, but device complexity increases
Solution Approach 1:
The thrust reverser system is segmented into multiple independently configured drag links, each optimized for its specific location in the bypass duct. This segmentation allows each drag link to be tailored to local flow conditions, reducing overall pressure loss while distributing the complexity across multiple simple, standardized components rather than one complex mechanism.
3Loss of energy
If drag links are circumferentially spaced about the engine core outer casing, then airflow alignment is optimized across the bypass duct, but manufacturing and installation complexity increases
Solution Approach 1:
The drag links are asymmetrically oriented relative to the bypass duct centerline, with each drag link angled differently based on its circumferential position. This asymmetric configuration optimizes airflow alignment across the non-uniform flow field in the bypass duct, and the angles can be determined through computational analysis prior to installation.
Data Source
AI summary
A gas turbine engine includes an engine core outer casing and a fan nacelle spaced radially outwardly relative to the engine core outer casing to define a bypass duct. A plurality of drag links is used to pivot blocker doors into a flow blocking position in the bypass duct when a thrust reverser is deployed. The plurality of drag links is located within the bypass duct in an area of non-uniform flow defined by a plurality of local airflow angles. Each drag link is individually configured to align with one of the local flow angles.